@article {pmid40359976,
year = {2025},
author = {Page, AE and Dyble, M and Migliano, A and Chaudhary, N and Viguier, S and Major-Smith, D},
title = {Demography of grandmothering: a case study in Agta foragers.},
journal = {Proceedings. Biological sciences},
volume = {292},
number = {2046},
pages = {20250385},
doi = {10.1098/rspb.2025.0385},
pmid = {40359976},
issn = {1471-2954},
support = {//Leverhulme Trust/ ; //John Templeton Foundation/ ; //Templeton Religion Trust/ ; },
mesh = {Humans ; *Grandparents ; Female ; Reproduction ; Middle Aged ; Bayes Theorem ; Demography ; },
abstract = {Grandmothers are often presented as key carers due to low costs and high inclusive fitness returns. Empirically, however, grandmothers are not consistently important. Understanding the factors that promote, or hinder, grandmothering is an important next step. We explore the demographic predictors of the low levels of grandmothering in Agta hunter-gatherers (78 children with 29 grandmothers). Due to generational reproductive timing, grandmothers still had dependent children until, on average 52, creating reproductive overlap. The minimal levels of grandmaternal investment after the age of 60 are explained by declining health and high mortality. This means the 'helping window' for grandmothering only spans 7 years. Yet grandmothers are still limited by multiple dependent grandchildren in this period, given high fertility. We suggest then that Agta grandmothering is constrained by (i) reproductive overlap and (ii) grandchildren competition. Accordingly, we tested how (i) the number of children and (ii) grandchildren associated with grandmothering using Bayesian mixed-effect models. We found moderate to strong evidence that more children/grandchildren reduced investment in each grandchild. Consequently, whether Agta grandmothers help appears dependent on demographic schedules, which vary widely both within and between populations. Future formal demographic modelling will then help shed light on the evolution of grandmothering in humans.},
}

Humans
*Grandparents
Female
Reproduction
Middle Aged
Bayes Theorem
Demography

@article {pmid40359158,
year = {2025},
author = {Shin, I and Hayden, S and Buzatto, BA},
title = {Mate competition and relatedness among males mediate the evolution of lethal fights in bulb mites.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/evolut/qpaf094},
pmid = {40359158},
issn = {1558-5646},
abstract = {Aggression can enhance direct fitness by aiding the aggressor's in securing reproductive resources, but it negatively impacts inclusive fitness when directed toward kin. We investigated the trade-off between the indirect fitness costs of aggression among kin and the direct benefits of increased success in mate competition using the bulb mite Rhizoglyphus echinopus, a male dimorphic species in which male fighters kill rivals with their modified third legs, while unmodified male scramblers seek unguarded females to mate. Our experiments showed that fighter aggression was never directed toward females, suggesting that fighter aggression evolved as a tactic to monopolize mates. Fighters grab other males before killing them, and grabbing behavior increased in the presence of a female, regardless of the presence of kin. Scrambler mortality increased with fighters' grabbing activity, but whereas the presence of mate competition increased lethal aggression, kinship decreased it, as higher mortality was observed among non-kin. These findings suggest that aggressive behavior intensifies under mate competition, but the decision to escalate aggression to lethal levels is influenced by kinship. In conclusion, this study provides insight into the trade-offs underlying kin-discriminatory aggression and direct benefits.},
}

@article {pmid40335688,
year = {2025},
author = {Earl, AD and Carter, GG and Berlinger, AG and Korir, E and Shah, SS and Watetu, WN and Rubenstein, DR},
title = {A cryptic role for reciprocal helping in a cooperatively breeding bird.},
journal = {Nature},
volume = {},
number = {},
pages = {},
pmid = {40335688},
issn = {1476-4687},
abstract = {Identifying the mechanisms that underlie cooperation is fundamental to biology[1]. The most complex form of cooperation in vertebrates occurs in cooperative breeders, in which helpers forego reproduction and assist in raising the young of others, typically relatives[2]. Not all cooperative societies, however, are kin-based-nearly half of all avian[3] and mammalian[4] cooperative breeders form mixed-kin societies, much like those of humans[5]. Kin selection in mixed-kin societies occurs when individuals gain indirect fitness from the preferential helping of relatives[6], but helpers also frequently assist non-kin[7], highlighting a potential role for direct fitness in stabilizing cooperative societies[7,8]. Here, using a 20-year study of superb starlings (Lamprotornis superbus), we examined how direct and indirect fitness jointly influence helping behaviour. Although we detected kin-biased helping (demonstrating kin selection), non-kin helping was common despite opportunities to aid kin. Unexpectedly, specific pairs maintained long-term reciprocal helping relationships by swapping social roles across their lifetimes-a subtle pattern of reciprocity requiring decades of observation to detect. Given the frequency of non-kin helping and the occurrence of reciprocal helping among both kin and non-kin, helping behaviour in superb starlings seems to be greatly influenced by direct fitness. However, the relative importance of direct and indirect fitness varied with helpers' sex and dispersal history. By uncovering a cryptic yet crucial role of long-term reciprocal helping, we suggest that reciprocity may be an underappreciated mechanism promoting the stability of cooperatively breeding societies.},
}

@article {pmid40333173,
year = {2025},
author = {Twyman, KZ and Gardner, A},
title = {The clonality window: relatedness and the group covariance effect in the evolution of division of labour.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/evolut/qpaf093},
pmid = {40333173},
issn = {1558-5646},
abstract = {Cellular division of labour is closely associated with the emergence of organismality in the evolution of obligate multicellularity. Michod has suggested that a trade-off between viability and fecundity may-through a 'group covariance effect'-lead to a group's fitness being augmented above the average of its constituents' fitnesses, offering a first step towards division of labour and obligate multicellularity. However, it is difficult to see how a group's fitness could be different from the aggregate of its constituents. Here, we investigate the same fitness trade-off and its consequences for division of labour. We recover the covariance effect, revealing that it is a consequence of cells sharing the products of their labours and clarifying that the group's fitness remains equal to the aggregate of the fitnesses of its constituent cells. We show that the covariance effect imparts an inclusive-fitness benefit for cells that share, but that-all else being equal-natural selection favours sharing only when groupmates are genetically identical, yielding a 'clonality window'. Lastly, we find that sharing is a critical determinant as to whether division of labour is favoured by natural selection, such that the 'clonality window' is also a prerequisite for division of labour in Michod's trade-off scenario.},
}

@article {pmid40305993,
year = {2025},
author = {Doria, HB and Sohal, N and Feldmeyer, B and Pfenninger, M},
title = {Size over substance: Microplastic particle size drives gene expression and fitness loss in a freshwater insect.},
journal = {Aquatic toxicology (Amsterdam, Netherlands)},
volume = {284},
number = {},
pages = {107386},
doi = {10.1016/j.aquatox.2025.107386},
pmid = {40305993},
issn = {1879-1514},
abstract = {Microplastics (MP) are a diverse class of contaminants for which it is challenging to assess their effects on freshwater biota. As polyamide (PA) and polyvinyl chloride (PVC) are two of the most abundant microplastic materials in natural environments, the present study investigated whether their chronic presence, particle size (< 100 μm and > 100 μm) and their mixture influenced gene transcription patterns and inclusive fitness of C. riparius. Transcriptome data as the lowest phenotypic trait level suggested that MP exposure impacted a range of organismic processes like oxidative stress and inflammations, leading to an innate immune response, downregulation of metabolism in organs directly exposed to the particles and triggered premature molting, regardless of the MP material or their mixture. A life-cycle fitness assessment was performed using PA, PVC and a mixture of both in, respectively. The integration of the fitness components survival, developmental time and fertility into the daily population growth rate as comprehensive fitness parameter on the highest trait level showed that any chronic microplastic exposure led to a considerable fitness loss. Partitioning the effects of substance and size class showed that microplastic exposure as such and size played an important role, while the MP material was of minor importance. The observed decrease in daily population growth rates between 2.3 and 7.6 % upon chronic MP exposure suggested a dramatic reduction of the species' population size and thus for freshwater ecosystems.},
}

@article {pmid40264365,
year = {2025},
author = {Kennedy, P and Higginson, AD},
title = {Brinkmanship in intragenomic conflict.},
journal = {Proceedings. Biological sciences},
volume = {292},
number = {2045},
pages = {20250488},
doi = {10.1098/rspb.2025.0488},
pmid = {40264365},
issn = {1471-2954},
support = {//Natural Environment Research Council/ ; },
mesh = {*Genomic Imprinting ; Game Theory ; Female ; Animals ; Male ; *Biological Evolution ; Humans ; Selection, Genetic ; },
abstract = {When the Darwinian interests of genes in the genome collide, intragenomic conflicts evolve. Recent advances in social evolution predict that intragenomic conflicts shape diverse phenotypes. However, principles governing which side wins remain unresolved. Here, we use game theory to predict that power asymmetries arise from differences in appetite for risk between rival genes in 'wars of nerve'. We focus on 'genomic imprinting': differing expression between alleles inherited from mothers and fathers. Escalating conflict is commonly believed to risk damaging the whole organism. We show that genes can exploit risk strategically: genes prepared to take greater risks with the body's vulnerability to disorders and mortality gain coercive advantages, deterring countermoves. Kin selection generates differences in appetite for risk: for instance, if harm to the body frees resources for maternal siblings, genes from mothers have less to lose from gambling with the current body than do genes from fathers. Seemingly maladaptive developmental risks can be adaptively useful for higher-nerve genes, much as political states manipulate risk to coerce rivals. Our results suggest a determinant of power alongside the 'loudest voice prevails' principle, and call for empirical investigation of the extent and means by which risks of imprinting-related disorders are amplified by intragenomic brinkmanship.},
}

*Genomic Imprinting
Game Theory
Female
Animals
Male
*Biological Evolution
Humans
Selection, Genetic

@article {pmid40261128,
year = {2025},
author = {Lee, M and Gonzalez, A and Rilling, JK},
title = {Grandmaternal caregiving is associated with a distinct multi-voxel neural representation of grandchildren in the parental motivation circuit.},
journal = {Social cognitive and affective neuroscience},
volume = {},
number = {},
pages = {},
doi = {10.1093/scan/nsaf034},
pmid = {40261128},
issn = {1749-5024},
support = {P50MH100023//National Institutes of Health (NIH)/ ; },
abstract = {Grandmothers enhances grandchild survival and maternal health through caregiving. Comparative evidence suggests that human grandmotherhood reflects a unique life history strategy promoting the inclusive fitness of post-reproductive females. Despite its evolutionary importance, the proximate neural mechanisms supporting grandmaternal caregiving remain unclear. This study uses functional magnetic resonance imaging (fMRI) and multivariate approaches to investigate how grandmaternal brains encode information about grandchildren and translate it into caregiving. Forty-seven grandmothers (Age = 59.1±7) completed an fMRI task viewing photos of a grandchild, the grandchild's parent, unfamiliar individuals, and non-human objects. Multi-voxel activation patterns associated with these stimuli were analyzed using representational similarity analysis, focusing on the hypothalamic and mesolimbic regions critical for mammalian parenting. Results reveal that grandchildren had most distinct multi-voxel pattern of activation within these regions, potentially reflecting the grandmothers' motivational readiness to engage in grandmaternal caregiving. Indeed, greater neural dissimilarity between the grandchild and other social categories correlated with higher self-reported affection and supportive behaviors towards grandchildren, particularly in paternal grandmothers. Our findings provide novel insights into the mechanisms of grandmaternal caregiving that enhances inclusive fitness.},
}

@article {pmid40240454,
year = {2025},
author = {Leroy, E and Gao, S and Gonzalez, M and Ellies-Oury, MP and Tuda, M},
title = {Wolbachia infection facilitates adaptive increase in male egg size in response to environmental changes.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {13213},
pmid = {40240454},
issn = {2045-2322},
support = {19K06840//JSPS/ ; },
mesh = {Animals ; *Wolbachia/physiology ; Male ; Female ; *Ovum/microbiology/physiology ; *Coleoptera/microbiology/physiology ; Climate Change ; Symbiosis ; *Adaptation, Physiological ; Environment ; Temperature ; Longevity ; },
abstract = {Under challenging conditions such as maladapted biotic and abiotic conditions, females can plastically adjust their egg size (gamete or zygote size) to counteract fitness declines early in life. Recent evidence suggests that endosymbionts may enhance this egg-size plasticity. Possible endosymbionts' modification of impact of multiple stressors is not well explored. Therefore, this study aims to test (1) whether Wolbachia infection influences the plasticity of parental investment in egg size under suboptimal environmental conditions and (2) whether the plasticity depends on the sex of eggs. We used three lines of the azuki bean beetle (Callosobruchus chinensis): a line coinfected with the wBruCon and wBruOri Wolbachia strains, a cured line infected solely with the wBruCon, and an uninfected (cured) line. These lines were subjected to either a control environment or a simulated climate change environment (elevated temperature and carbon dioxide levels, eT&CO2) to examine Wolbachia infection effects on parental investment in their offspring (egg size) and its subsequent impact on offspring fitness, including survival, development, and adult lifespan under starvation. After two days of eT&CO2 exposure, coinfected parents increased male egg size only. Larger eggs developed faster in both sexes and exhibited higher survival. However, offspring adult lifespan was not influenced by egg size but by environment, sex, Wolbachia infection, and development time: eT&CO2 reduced male lifespan but not female lifespan, the singly-infected line females lived longer than coinfected and uninfected line females, and shorter development time linked to longer lifespan. The negative correlation between development time and lifespan was higher under eT&CO2 but not sex-specific. This study is the first to demonstrate sex-specific egg size plasticity associated with Wolbachia infection in species with sex determination systems other than haplodiploid.},
}

Animals
*Wolbachia/physiology
Male
Female
*Ovum/microbiology/physiology
*Coleoptera/microbiology/physiology
Climate Change
Symbiosis
*Adaptation, Physiological
Environment
Temperature
Longevity

@article {pmid40171117,
year = {2025},
author = {Troisi, A},
title = {"Are You Sick? No, I am Neurodivergent!" The Perilous Navigation Between Medicalization and Diagnostic Nihilism.},
journal = {Clinical neuropsychiatry},
volume = {22},
number = {1},
pages = {5-8},
pmid = {40171117},
issn = {2385-0787},
abstract = {When advocating to fight stigma and promote acceptance of neurodivergent individuals, the current debate on neurodiversity does not present a major challenge to psychiatric theory and research. The controversy arises when neurodiversity is taken to its extreme, denying the existence of neurodevelopmental disorders. Evolutionary psychiatry has recently contributed to the neurodiversity debate by providing adaptive explanations. These explanations are based on the unproven assumption that neurodiversity has been shaped by natural selection, as some atypical neurocognitive profiles increased inclusive fitness in the ancestral environment. Evolutionary psychiatry recognizes the heterogeneity of neurodiversity, acknowledges the existence of neurodevelopmental disorders, and establishes fitness disadvantage as the criterion of morbidity. The evolutionary definition of pathological neurodiversity is based on an objective criterion but it has limited utility in clinical practice. Cultural relativism has always played a role in the history of medicine and psychiatry, often overshadowing scientific analysis. Therapeutic concerns are influenced by cultural trends that can lean towards either medicalization or diagnostic nihilism.},
}

@article {pmid40157047,
year = {2025},
author = {Kristensen, NP and Chisholm, RA and Ohtsuki, H},
title = {Many-strategy games in groups with relatives and the evolution of coordinated cooperation.},
journal = {Journal of theoretical biology},
volume = {605},
number = {},
pages = {112089},
doi = {10.1016/j.jtbi.2025.112089},
pmid = {40157047},
issn = {1095-8541},
abstract = {Humans often cooperate in groups with friends and family members with varying degrees of genetic relatedness. Past kin selection can also be relevant to interactions between strangers, explaining how the cooperation first arose in the ancestral population. However, modelling the effects of relatedness is difficult when the benefits of cooperation scale nonlinearly with the number of cooperators (e.g., economies of scale). Here, we present a direct fitness method for rigorously accounting for kin selection in n-player interactions with m discrete strategies, where a genetically homophilic group-formation model is used to calculate the necessary higher-order relatedness coefficients. Our approach allows us to properly account for non-additive fitness effects between relatives (synergy). Analytical expressions for dynamics are obtained, and they can be solved numerically for modestly sized groups and numbers of strategies. We illustrate with an example where group members can verbally agree (cheap talk) to contribute to a public good with a sigmoidal benefit function, and we find that such coordinated cooperation is favoured by kin selection. As interactions switched from family to strangers, in order for coordinated cooperation to persist and for the population to resist invasion by liars, either some level of homophily must be maintained or following through on the agreement must be in the self-interests of contributors. Our approach is useful for scenarios where fitness effects are non-additive and the strategies are best modelled in a discrete way, such as behaviours that require a cognitive 'leap' of insight into the situation (e.g., shared intentionality, punishment).},
}

@article {pmid40153445,
year = {2025},
author = {Jones, D},
title = {Extraordinary siblings: Mole rats, marmosets, and Radcliffe-Brown.},
journal = {PloS one},
volume = {20},
number = {3},
pages = {e0319385},
doi = {10.1371/journal.pone.0319385},
pmid = {40153445},
issn = {1932-6203},
mesh = {Animals ; *Siblings ; *Mole Rats/genetics ; Humans ; Altruism ; Biological Evolution ; Male ; Female ; Callithrix ; Game Theory ; },
abstract = {According to the theory of kin selection, an organism that shows some level of altruism toward her kin - lowering her own fitness, raising that of a close genetic relative - may enjoy an evolutionary advantage. Some species show beyond-ordinary altruism toward siblings, and other kin, owing to unusual reproductive biology and/or ecology. Human beings are exceptional in another way: how we treat our kin depends partly on how we feel about them, but also partly on socially enforced norms. This article explores several versions of a simple evolutionary game, the Brothers Karamazov Game, that departs from the standard theory of kin selection to allow for the distinctively human capacity for establishing and enforcing social norms. We discuss possible applications to understanding the "unity of the sibling group" (Radcliffe-Brown) - according exceptional treatment to siblings, and to relatives classified as siblings or linked through siblings. We give special attention to lowland South America, where the sibling relationship is central to social organization.},
}

Animals
*Siblings
*Mole Rats/genetics
Humans
Altruism
Biological Evolution
Male
Female
Callithrix
Game Theory

@article {pmid40152585,
year = {2025},
author = {Wang, F and Luo, J and Zhang, Z and Liu, Y and Sheng, Dh and Zhuo, L and Li, Y-z},
title = {Differential crosstalk between toxin-immunity protein homologs divides Myxococcus nonself siblings into close and distant social relatives.},
journal = {mBio},
volume = {},
number = {},
pages = {e0390224},
doi = {10.1128/mbio.03902-24},
pmid = {40152585},
issn = {2150-7511},
abstract = {Many bacteria discriminate self and nonself using toxins and their corresponding immunity proteins. The toxin-immunity systems often include homologs, potentially creating crosstalk with unknown influences on kin discrimination. In this study, we investigated the kinship controlled by four homologous toxin-immunity systems in the social bacterium Myxococcus xanthus. We determined that the four homologous systems each play an independent role in the discrimination of self and nonself. However, the immunity proteins inactivate not only the corresponding nuclease toxin proteins but also some non-corresponding toxin proteins, depending on their sequence and structural similarities. The nonself relatives controlled by toxin-immunity proteins with or without crosstalk exhibit differential co-growth and collaborative behaviors. We concluded that differential crosstalk between toxin-immunity protein homologs can divide bacterial nonself lineages into close and distant relatives displaying differential collaboration and antagonistic behaviors.IMPORTANCEThis study significantly contributes to our knowledge of kin selection and social behavior in bacteria. The interactions between four homologous toxin-immunity protein systems of Myxococcus xanthus were investigated, and evidence was obtained that these systems can distinguish between self and nonself cells within a species. Importantly, this study revealed that nonself lineages, which display varying degrees of genetic relatedness, can co-grow and collaborate in distinct patterns. This discovery implies that the differential crosstalk between homologous toxin-immunity proteins can mimic the degree of kinship; through this activity, bacteria can differentiate close and distant relatives. This novel insight into bacterial social dynamics and kin discrimination supports kin selection theory and enriches our knowledge on microbial interactions and evolutionary strategies. These findings have broad implications for microbial ecology, evolution, and the development of cooperation strategies.},
}

@article {pmid40124613,
year = {2025},
author = {Burnett, A and Hein, M and Payne, N and Vargas, KL and Culver, M and Koprowski, JL},
title = {Female philopatry may influence antipredatory behavior in a solitary mammal.},
journal = {PeerJ},
volume = {13},
number = {},
pages = {e18933},
doi = {10.7717/peerj.18933},
pmid = {40124613},
issn = {2167-8359},
mesh = {Animals ; Female ; *Sciuridae/genetics/physiology ; Male ; Vocalization, Animal/physiology ; Social Behavior ; Behavior, Animal/physiology ; Sex Factors ; },
abstract = {Whether neighboring individuals are related or not has a number of important ecological & evolutionary ramifications. Kin selection resulting from philopatry can play an important role in social and antipredatory behavior. Ground squirrels exhibit alarm vocalizations in the presence of predators; however, the degree to which kin selection shapes alarm calling behavior varies with species ecology and the degree of relatedness between neighbors. We studied a solitary ground squirrel species that exhibits sex-biased calling propensity to determine if female philopatry may be responsible for sex differences in antipredatory behavior observed in our population. We used double digest restriction-site associated DNA sequencing (ddRADseq) to sample the genomes of Harris's antelope squirrel (Ammospermophilus harrisii) to determine the relatedness between individuals and test whether genetic and geographic distance were correlated. We found that geographic distance had a positive relationship with genetic distance, and that this relationship was sex-dependent, suggesting male-biased dispersal. Our results provide supporting evidence that female philopatry may be responsible for higher calling propensity observed in female squirrels, potentially influencing antipredatory behavior in this species via kin selection. Our findings add to a growing body of evidence that philopatry is an important ecological driver influencing sociospatial organization in solitary species.},
}

Animals
Female
*Sciuridae/genetics/physiology
Male
Vocalization, Animal/physiology
Social Behavior
Behavior, Animal/physiology
Sex Factors

@article {pmid40109113,
year = {2025},
author = {Rodrigues, AMM and Riehl, C},
title = {The evolution of cooperative breeding in family groups: when should parents tolerate unhelpful helpers?.},
journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences},
volume = {380},
number = {1922},
pages = {20230275},
doi = {10.1098/rstb.2023.0275},
pmid = {40109113},
issn = {1471-2970},
support = {IOS-184543//National Science Foundation/ ; },
mesh = {Animals ; *Cooperative Behavior ; *Biological Evolution ; Reproduction ; Helping Behavior ; Female ; },
abstract = {Cooperatively breeding vertebrates typically live in family groups in which some offspring delay breeding and remain on the natal territory to help rear younger siblings. However, field studies find that helpers can have a neutral or even negative effect on the survival of their relatives. Why, then, do helpers remain, and why do parents tolerate them? Here, we use a kin selection approach to model the conditions under which tolerating helpers is adaptive to parents. Unlike previous models, we consider scenarios in which relatives compete for breeding opportunities in a saturated habitat. We show that kin competition is sufficient to favour tolerance of helpers, even when helpers decrease parental survival or fecundity. Helping is additionally favoured when delaying dispersal benefits the helper (either by decreasing the costs of dispersal or by increasing the chance of territory inheritance). This suggests that the division of reproduction in cooperative family groups can emerge for reasons unrelated to the effects of help itself, but the resulting society sets the stage for more elaborate forms of division of labour. Kin-based helping may therefore be adaptive not only because helpers are related to the brood whom they help, but also because delayed breeding reduces reproductive conflict among siblings.This article is part of the theme issue 'Division of labour as a key driver of social evolution'.},
}

Animals
*Cooperative Behavior
*Biological Evolution
Reproduction
Helping Behavior
Female

@article {pmid40085345,
year = {2025},
author = {Clark, KJ and Walker, RS},
title = {Iban Kinship and Cooperation : A Test of the Ancestor-Descendant Conflict Model.},
journal = {Human nature (Hawthorne, N.Y.)},
volume = {},
number = {},
pages = {},
pmid = {40085345},
issn = {1936-4776},
abstract = {Humans often display extensive forms of prosocial behavior, frequently beyond what is predicted by inclusive fitness. This observation has led to various models attempting to explain the unique extent of human altruism. While many of these models have been empirically tested, one model, the ancestor-descendant conflict model, which is based on a maximum descendant-leaving strategy, has yet to be explicitly examined with observational human data. The ancestor-descendant conflict model posits that ancestors influence the behavior of their descendants, through traditions passed down from generation to generation, and predicts that humans in traditional societies will favor, both altruistically and cooperatively, their closer kin even at greater genealogical distances than predicted by inclusive fitness. In this paper, we specifically examine the strength of ancestor influence on prosociality using observational (n = 863) and interview (n = 28) data collected with the Iban of West Kalimantan, Indonesia (Borneo). We evaluate kinship cooperation norms, kinship's role in cooperative interactions, and the strength of ancestor influence on those interactions with dyadic data (unique dyads = 668). We find strong norms and behaviors for individuals cooperating more often with closer kin, while also finding limited support for the influence of ancestors on actual cooperative behavior.},
}

@article {pmid40083783,
year = {2025},
author = {Lan, G and Ma, R and Zhou, Y and Lu, Z and Zhu, B and Liu, J and Wu, W and Zhang, Y and Liu, J and Gu, H and Lin, J and Wei, W and Qi, D},
title = {Gut microbiota alterations in golden snub-nosed monkeys during food shortage and parturition-nursing periods.},
journal = {Frontiers in microbiology},
volume = {16},
number = {},
pages = {1556648},
pmid = {40083783},
issn = {1664-302X},
abstract = {Adopting unique survival strategies during spring food shortages and simultaneous parturition and nursing is crucial for golden snub-nosed monkeys. Social behaviors, such as altruism within one-male units (OMUs), are decisive for family health, but the role of microbiota in regulating these behaviors remains unknown. We conducted the gut microbiota from members of 10 OMUs using 16S RNA sequencing technology. We found that in adult males, gut microbiota diversity significantly decreased in food shortages and parturition-nursing period. Meanwhile, there was a notable reduction in 12 metabolism-related pathways, including those related to carbohydrates, amino acids, and lipid. The gut microbiota of adult male monkeys shifts from being enriched with the genera Akkermansia in winter to the genera norank Muribaculaceae in spring. This transition alters the pathways for nutrient acquisition, thereby reducing the consumption of stored energy. In contrast, other OMU members (adult females and subadults) did not experience adverse effects on the metabolic functions of their gut microbiota during the food-scarce spring, which is also a critical period for parturition and lactation in adult females. This study elucidates the co-evolution of altruistic behavior and gut microbiota in Sichuan snub-nosed monkeys, insights into the interaction mechanisms between mammalian microbiota and survival strategies.},
}

@article {pmid40065655,
year = {2025},
author = {Frank, SA},
title = {Natural selection at multiple scales.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/evolut/qpaf037},
pmid = {40065655},
issn = {1558-5646},
abstract = {Natural selection acts on traits at different scales, often with opposing consequences. This article identifies the particular forces that act at each scale and how those forces combine to determine the overall evolutionary outcome. A series of extended models derive from the tragedy of the commons, illustrating opposing forces at different scales. Examples include the primary tension between conflict and cooperation and the evolution of virulence, sex ratios, dispersal, and evolvability. The unified analysis subsumes interactions within and between species by generalizing multitrait interactions. Expanded notions of recombination and cotransmission arise. The core theoretical approach isolates the fundamental forces of selection, including marginal valuation, correlation between interacting entities, and reproductive value. Those fundamental forces act as partial causes that combine at different temporal and spatial scales. Modeling focuses on statics, in the sense of how different forces at various scales tend to oppose each other, ultimately combining to shape traits. That type of static analysis emphasizes explanation rather than the calculation of dynamics. The article builds on the duality between explanation versus calculation in terms of statics versus dynamics. The literature often poses that duality as a controversy, whereas this article develops the pair as complementary tools that together provide deeper understanding. Along the way, the unified approach clarifies the subtle distinctions between kin selection, multilevel selection, and inclusive fitness, subsuming these topics into the broader perspectives of fundamental forces and multiple scales.},
}

@article {pmid40040457,
year = {2025},
author = {Tureček, P and Fořt, J and Flegr, J},
title = {Crusaders, monks and family fortunes: evolutionary models of male homosexuality and related phenomena.},
journal = {Proceedings. Biological sciences},
volume = {292},
number = {2042},
pages = {20242756},
doi = {10.1098/rspb.2024.2756},
pmid = {40040457},
issn = {1471-2954},
support = {//Charles University Research Centre program/ ; //Grantová Agentura, Univerzita Karlova/ ; },
mesh = {Male ; Humans ; *Homosexuality, Male ; *Biological Evolution ; Birth Order ; },
abstract = {The fraternal birth order effect (FBOE) is a well documented preponderance of older brothers among gay men. Until now, it has lacked a proper formal treatment in light of evolutionary theory. In this article, we propose two related mathematical models based on the rigorous application of the inclusive fitness concept. The models examine sibling rivalry and resource allocation within families. One of the models assumes that the laterborn's reproductive ability is not compromised by the manipulation that leads to the exclusive allocation of family resources to the firstborn. The other model posits that this manipulation may lower the laterborn's direct fitness to zero. Both models suggest that the FBOE arises primarily from the older brother's manipulation, as the firstborn's inclusive fitness may increase, while the mother's decreases, but not vice versa. However, under certain conditions, the mother should support an activity that discourages division of family resources, and in extreme cases, the younger brother's homosexuality may be the best available reproductive strategy for his genes. The models also provide insight into the cultural evolution of primogeniture and explain how manipulation between relatives could evolve before the emergence of substantial economic inequality.},
}

Male
Humans
*Homosexuality, Male
*Biological Evolution
Birth Order

@article {pmid39957726,
year = {2024},
author = {Giaimo, S and Traulsen, A},
title = {Juvenile mortality and sibling replacement: a kin selection approach.},
journal = {Evolution letters},
volume = {8},
number = {5},
pages = {647-657},
pmid = {39957726},
issn = {2056-3744},
abstract = {Mortality generally is higher around birth and then progressively declines through the juvenile stage. In species where offspring depend upon their parents during maturation, a factor behind this mortality decline could be sibling replacement: offspring sacrifice their survival to benefit future or present siblings as early as possible in order to minimize losses in parental investment. Here, we propose a kin-selection model of sibling replacement. Theoretical analysis of the model and its application to demographic data of mammals suggest that sibling replacement consistently generates a selective incentive for increasing juvenile mortality at early ages when this mortality increment is the result of positive selection for juvenile altruism within the nuclear family. The model highlights how sibling replacement goes beyond optimal allocation of parental resources into dependents and can provoke greater mortality closer to birth also in response to a more favorable ratio of actors to recipients of altruism among siblings.},
}

@article {pmid39955103,
year = {2025},
author = {Scott, TW and Wild, G and Gardner, A},
title = {Kin-discriminating partner choice promotes the evolution of helping.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/evolut/qpaf032},
pmid = {39955103},
issn = {1558-5646},
abstract = {Kin selection theory predicts that individuals should evolve to help relatives, either by helping indiscriminately in a population where they do not move very far from their relatives, or by discriminating kin and conditionally helping them. It has been argued that, because kin discrimination enables individuals to reduce how helpful they are with some social partners as well increase how helpful they are with others, this could lead to an increase or a decrease in the overall level of helping. Specifically, it was argued that kin discrimination would increase the overall level of helping if the function relating the optimal level of help and genetic relatedness is convex, but kin discrimination would decrease the overall level of helping if the function relating the optimal level of help and genetic relatedness is concave. However, this prediction was based on a model in which individuals were not able to choose their social partners but only adjust how helpful they should be towards those social partners they have been allocated. Here, we perform a mathematical analysis showing that being able to choose social partners increases the overall level of helping. Consequently, if kin discriminators are allowed to choose whom they help, kin discrimination is more likely to increase the overall level of helping than previously anticipated. We obtained these results in two complementary theoretical settings: one more general, which makes few demographic assumptions, and the other more specific and concrete, which assumes a patch-structured population with complete dispersal.},
}

@article {pmid39948360,
year = {2025},
author = {Gibson, SER and Frost, I and Hierons, SJ and Moses, T and Poon, WCK and West, SA and Cann, MJ},
title = {Bacteria encode post-mortem protein catabolism that enables altruistic nutrient recycling.},
journal = {Nature communications},
volume = {16},
number = {1},
pages = {1400},
pmid = {39948360},
issn = {2041-1723},
mesh = {*Protease La/metabolism/genetics ; *Nutrients/metabolism ; Bacterial Proteins/metabolism/genetics ; Escherichia coli/metabolism/genetics ; },
abstract = {Bacterial death is critical in nutrient recycling. However, the underlying mechanisms that permit macromolecule recycling after bacterial death are largely unknown. We demonstrate that bacteria encode post-mortem protein catabolism via Lon protease released from the dead bacteria. Growth assays reveal that the lysate of Lon protease-null bacteria does not provide a growth benefit to wild type cells. This deficiency is reversed with exogenous recombinant Lon protease, confirming its post-mortem role and is independent of Lon ATPase activity. Biochemistry, growth assays and metabolomics demonstrate that Lon protease facilitates peptide nutrient release, benefitting living cells and acting as a cooperative public good. We also show that the production of Lon protease cannot be explained by a personal benefit to living cells. Although Lon protease can also provide a benefit to living cells under stressful conditions by helping control protein quality, this private benefit does not outweigh the cost under the conditions examined. These results suggest that Lon protease represents a post-mortem adaptation that can potentially be explained by considering the post-mortem indirect benefit to other cells (kin selection). This discovery highlights an unexpected post-mortem biochemistry, reshaping our understanding of nutrient recycling.},
}

*Protease La/metabolism/genetics
*Nutrients/metabolism
Bacterial Proteins/metabolism/genetics
Escherichia coli/metabolism/genetics

@article {pmid39903786,
year = {2025},
author = {Graser, C and Fujiwara-Greve, T and García, J and van Veelen, M},
title = {Repeated games with partner choice.},
journal = {PLoS computational biology},
volume = {21},
number = {2},
pages = {e1012810},
doi = {10.1371/journal.pcbi.1012810},
pmid = {39903786},
issn = {1553-7358},
abstract = {Repetition is a classic mechanism for the evolution of cooperation. The standard way to study repeated games is to assume that there is an exogenous probability with which every interaction is repeated. If it is sufficiently likely that interactions are repeated, then reciprocity and cooperation can evolve together in repeated prisoner's dilemmas. Who individuals interact with can however also be under their control, or at least to some degree. If we change the standard model so that it allows for individuals to terminate the interaction with their current partner, and find someone else to play their prisoner's dilemmas with, then this limits the effectiveness of disciplining each other within the partnership, as one can always leave to escape punishment. The option to leave can however also be used to get away from someone who is not cooperating, which also has a disciplining effect. We find that the net effect of introducing the option to leave on cooperation is positive; with the option to leave, the average amount of cooperation that evolves in simulations is substantially higher than without. One of the reasons for this increase in cooperation is that partner choice creates endogenous phenotypic assortment. Compared to the standard models for the co-evolution of reciprocity and cooperation, and models of kin selection, our model thereby produces a better match with many forms of human cooperation in repeated settings. Individuals in our model end up interacting, not with random others that they cannot separate from, once matched, or with others that they are genetically related to, but with partners that they choose to stay with, and that are similarly dependable not to play defect as they are themselves.},
}

@article {pmid39873340,
year = {2025},
author = {Morinay, J and Woodward, BK and Russell, AF and Sharp, SP and Hatchwell, BJ},
title = {Ecological and demographic drivers of kin-directed cooperation in a social bird: Insights from a long-term study.},
journal = {The Journal of animal ecology},
volume = {},
number = {},
pages = {},
doi = {10.1111/1365-2656.14237},
pmid = {39873340},
issn = {1365-2656},
support = {//Leverhulme Trust/ ; //University of Sheffield/ ; EP/X023753/1//Engineering and Physical Sciences Research Council/ ; //Natural Environment Research Council/ ; //Nuffield Foundation/ ; //Association for the Study of Animal Behaviour/ ; },
abstract = {The evolution of sociality is one of the major evolutionary transitions in the history of life and a key step in this transition is the occurrence of kin associations. Yet, the question of what demographic processes and environmental factors generate kin-structured populations and drive kin-directed cooperation remains open. In this review, we synthesise 30 years of studies of the long-tailed tit Aegithalos caudatus, which has a kin-selected cooperative breeding system with redirected help: failed breeders may help to raise offspring of conspecifics, typically relatives, breeding nearby. We describe the use of ecological, demographic, genetic and behavioural approaches to reveal: (a) how kin-structured populations (here 'kin neighbourhoods') arise; (b) why the prevalence of cooperation varies among populations and individuals; and (c) how variation in dispersal and opportunities for cooperation influence individual fitness. The kin neighbourhoods of long-tailed tits arise from three processes. First, natal dispersal is limited and sex-biased so many individuals, especially males, recruit as breeders close to their natal site. Second, neither dispersal nor migration necessarily disrupts kin associations because long-tailed tits often move with close relatives. Third, a small effective population size driven by high nest predation rates enhances within-population relatedness. Together, these processes set the scene for kin-directed helping behaviour by causing spatial clustering of relatives. The prevalence of cooperation within kin neighbourhoods depends on several factors, both at the population-level (annual nest predation rate and length of the breeding season) and individual-level (relatedness, familiarity, sex and condition). However, limited information on prior social association and the reliability of kin discrimination cues hampers our current understanding of individual helping decisions. Finally, variation in dispersal within and between sexes affects the probability of interacting with kin, the likelihood of cooperation, and accrual of the direct and indirect components of inclusive fitness. We use this comprehensive understanding of the factors driving cooperative behaviour in long-tailed tits to highlight gaps in knowledge and suggest future avenues for research in this system, and to make general inferences about the role of dispersal, demography and kinship in social evolution.},
}

@article {pmid39836487,
year = {2025},
author = {Rai, S and Mishra, G},
title = {Digest: Evolution of redirected help in a viscous population.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/evolut/qpaf008},
pmid = {39836487},
issn = {1558-5646},
abstract = {When broods fail, parents may assist neighbours' offspring, a behaviour called redirected helping that is observed in many species. Flatrès and Wild (2024) used inclusive fitness models to study this behaviour. They showed that redirected helping can evolve in viscous populations, where individuals stay near their birthplace, increasing relatedness and competition among neighbours, especially when helping costs are low. Life-history traits like survival, dispersal, and brood-failure rates shape this behaviour. Interestingly, survival benefits from helping can outweigh reproductive gains, challenging assumptions and providing fresh insights into cooperative breeding dynamics.},
}

@article {pmid39816451,
year = {2025},
author = {Dong, B and Gardner, A},
title = {Kin Competition Drives the Evolution of Earlier Metamorphosis.},
journal = {Ecology and evolution},
volume = {15},
number = {1},
pages = {e70806},
pmid = {39816451},
issn = {2045-7758},
abstract = {Metamorphosis, the discrete morphological change between postembryonic life stages, is widespread across the animal kingdom. The suggested advantages of metamorphosis have usually been framed in terms of population benefits, i.e., ecological explanations. In contrast, evolutionary explanations concern whether and how metamorphosis spreads through a population owing to individual-fitness benefits. However, how kin selection modulates evolution of metamorphosis remains to be investigated formally. Here we develop a mathematical model to investigate how kin selection shapes the optimal timing of metamorphosis from foraging, non-reproductive larva to reproductive adult, when larvae tend to cluster with their genetic relatives. We consider the full range of larval competition intensities-from no competition to full competition-and the full range of relatedness coefficients-from unrelated to clonality. We provide testable predictions as to how kin selection modulates the timing of metamorphosis, as well as a conceptual framework within which empirical observations may be understood.},
}

@article {pmid39765505,
year = {2024},
author = {Allen Wild, C and Yon, L},
title = {Commentary on the Adaptive Significance of Sociality Around Parturition Events, and Conspecific Support of Parturient Females in Some Social Mammals.},
journal = {Animals : an open access journal from MDPI},
volume = {14},
number = {24},
pages = {},
doi = {10.3390/ani14243601},
pmid = {39765505},
issn = {2076-2615},
abstract = {In recent decades, it has become apparent that during parturition events in a number of social mammals, social support behaviours from group mates can be directed to parturient females (and their newborn neonates). Such behaviour has been documented in diverse taxa, across non-human primates, Elephantidae, Cetacea, and Chiroptera, living in a range of social group organisations, from matrilineal groups to cooperatively breeding groups and multi-male, multi-female groups. Since sociality, in association with parturition, has been demonstrated to confer several health benefits to human mothers and neonates, here, we also consider the potential adaptive significance of social support behaviours for other, non-human, social mammals. If appropriate social environments reduce a parturient female's dystocia risk and improve her responsiveness to her neonate following a successful birth, then the impacts of the peri-parturient social environment may ultimately have far-reaching impacts on the mother-neonate dyad's fitness. This seems a logical sequela since the health condition of a neonate at birth and the successful establishment of a strong maternal-neonate bond are often the most critical factors influencing mammalian offspring survival to independence. The principles of kin selection and alliance enhancement may serve to explain the fitness benefits to individuals who support group mates during their parturition and thus the selective advantage conferred to those exhibiting such behaviours. Older, multiparous females appear to hold a particularly important role in the assistance they can provide during the parturition of their group mates, given their greater level of experience of these events. Furthermore, a social birth may have an important influence on horizontal information transfer within a group. In particular, in long-lived, cognitively advanced social mammals (e.g., non-human primates, Elephantidae, Cetacea), witnessing birth events, early neonate responses, and maternal care, and engaging in allomaternal care with young neonates may be essential for nulliparous females' normal development. Such events may serve to prepare them for their own parturition and may improve their own parturition-related survivorship and that of their first-born offspring. Thus, it is vital that a better understanding is gained of the importance and salient features of social births in improving the health and survivorship outcomes for both the mother and her offspring in highly social species. The aim of this commentary is to assemble our current understanding of these highly interconnected themes. We suggest in the future, insights gained through observation of non-human social parturition in domestic and non-domestic species, by a wide and highly interdisciplinary range of stakeholders (including zookeepers, wildlife tourism guides, breeders of domestic animals, indigenous people, and ethologists), will be critical for enhancing our understanding of the influence of social environment on this rarely witnessed, yet highly important life event.},
}

@article {pmid39679295,
year = {2024},
author = {Engelhardt, SC and Paulsson, NI and Taborsky, M},
title = {Norway rats recruit cooperation partners based on previous receipt of help while disregarding kinship.},
journal = {iScience},
volume = {27},
number = {12},
pages = {111314},
pmid = {39679295},
issn = {2589-0042},
abstract = {Norway rats are known to liberate trapped conspecifics, which implies an empathic response to the deplorable situation of the captive. If this is an altruistic behavior reflecting an evolved decision rule, the requisite fitness enhancement to the actor may result either from close relatedness or the expectation of future returns. Neither potential effects of relatedness nor of reciprocal returns have yet been examined. Our two-stage experiment revealed that wild-type Norway rats preferably collaborated with partners that had previously freed them from a trap and subsequently cooperated with each other, indicating that expected future benefits may underlie the deliverance of trapped companions. Relatedness had no effect on their cooperative propensity. These results show that rats recruit partners to coordinate cooperation by direct reciprocity but not kin discrimination, suggesting that the evolutionary mechanism responsible for the altruistic liberation behavior of Norway rats may be reciprocal altruism rather than kin selection.},
}

@article {pmid39667707,
year = {2024},
author = {Jordan, F and Hutzenthaler, M and Metzler, D},
title = {Selection for altruistic defense in structured populations.},
journal = {Theoretical population biology},
volume = {},
number = {},
pages = {},
doi = {10.1016/j.tpb.2024.11.001},
pmid = {39667707},
issn = {1096-0325},
abstract = {We model natural selection for or against an anti-parasite (or anti-predator) defense allele in a host (or prey) population that is structured into many demes. The defense behavior has a fitness cost for the actor compared to non defenders ("cheaters") in the same deme and locally reduces parasite growth rates. Hutzenthaler et al. (2022) have analytically derived a criterion for fixation or extinction of defenders in the limit of large populations, many demes, weak selection and slow migration. Here, we use both individual-based and diffusion-based simulation approaches to analyze related models. We find that the criterion still leads to accurate predictions for settings with finitely many demes and with various migration patterns. A key mechanism of providing a benefit of the defense trait is genetic drift due to randomness of reproduction and death events leading to between-deme differences in defense allele frequencies and host population sizes. We discuss an inclusive-fitness interpretation of this mechanism and present in-silico evidence that under these conditions a defense trait can be altruistic and still spread in a structured population.},
}

@article {pmid39658270,
year = {2024},
author = {Flatrès, A and Wild, G},
title = {Selective advantage of redirected helping in a viscous population.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/evolut/qpae175},
pmid = {39658270},
issn = {1558-5646},
abstract = {When a brood fails, the failed parent can help a neighbor rear its offspring. This behavior is known as redirected helping and occurs in various species. The advantage of redirected helping may seem obvious, provided the individual whose brood fails helps a related neighbor: the helper at least gains indirect fitness by redirecting its parental effort. However, complications arise when considering a viscous population, where individuals remain on or close to their natal site. In such a population, individuals compete with relatives, which dilutes the advantage of helping and may counteract it altogether. This raises a question: when can we expect redirected helping to evolve in a viscous population? We address this question with inclusive fitness models. We find that redirected helping can always be favored in a viscous population, provided the cost is sufficiently low. We also identify life-history features - like survival, dispersal, and brood-failure rate - that promote redirected helping. The effect of these life-history features, in general, depends on which component of fitness (survival or fecundity) benefits from help and how brood failure varies among demes. Unlike previous authors, we find that helping can be more strongly promoted when it provides survival rather than fecundity benefits.},
}

@article {pmid39653881,
year = {2024},
author = {Gilles, DR and Bay-Jouliá, R and Sánchez-Gavier, F and Kowalewski, MM},
title = {Male adoption in the black and gold howler monkey (Alouatta caraya).},
journal = {Primates; journal of primatology},
volume = {},
number = {},
pages = {},
pmid = {39653881},
issn = {1610-7365},
support = {ID:G20221001-4095//Sigma Xi, the Scientific Research Honor Society/ ; },
abstract = {Infant adoption is an association that occurs between an adult individual and a dependent infant and occurs most often when lactating females care for a nutritionally dependent infant that is not her offspring. Adult females are often involved in adoption; while, direct infant care by males occurs in less than 5% of all mammalian species. We report the first record of adoption by wild male adults of Alouatta caraya, a platyrrhine primate species that does not typically participate in parental care. We observed two independent cases of adoption, in two different groups (G1, G2) at the Corrientes Biological Station, Argentina. After the death of two adult females with dependent infants, one adult male adopted an orphan in each group. We recorded the activity of the adoptive males and the two infants. During this period, adoptive males expressed parental care behaviors toward infants. However, after 38 days in G1 and 53 days in G2, both infants died. Based on our continuous monitoring of study groups, we suggest that adoptive males are the biological parents of the orphaned infants. As such, kin selection may explain the care of the infants. However, another explanation could be group familiarity, which refers to the social bonds and cohesion that develop among individuals within a group, even if they are not genetically related. An adult male, although not genetically related to the infants, may take care of them due to the cohesion and relationships established within the group during his period of residence. The study of these rare parental behaviors taken by A. caraya adult males provide insights into the knowledge of group social cohesion and structure.},
}

@article {pmid39556049,
year = {2024},
author = {Rautiala, P and Lehtonen, J},
title = {Juvenile and total reproductive values for sexual reproduction under any genetic system.},
journal = {Evolution; international journal of organic evolution},
volume = {},
number = {},
pages = {},
doi = {10.1093/evolut/qpae163},
pmid = {39556049},
issn = {1558-5646},
abstract = {Reproductive value (RV) is the expected contribution of genes by an individual or class of individuals to the gene pool in the distant future, and it plays a crucial role in understanding adaptation in long-term evolution. Class RVs are linked to the genetic system and to life history: for diploid genetics, Grafen derived expressions for relative RVs of female and male juveniles, and for the absolute RVs of all females and of all males. Subsequently, Gardner presented a derivation for relative RVs of juvenile females and males under haplodiploidy. Here we generalise these results to any genetic system for biparental sexual reproduction, such that RV is explicitly linked to parameters of the genetic system and life history. The earlier results by Grafen and Gardner arise as special cases. Finally, we derive expressions for absolute juvenile and total reproductive values of both sexes under any genetic system.},
}

@article {pmid39486033,
year = {2024},
author = {Van Dyken, JD and Zee, PC},
title = {Disentangling the Factors Selecting for Unicellular Programmed Cell Death.},
journal = {The American naturalist},
volume = {204},
number = {5},
pages = {468-481},
doi = {10.1086/732199},
pmid = {39486033},
issn = {1537-5323},
mesh = {*Apoptosis ; *Biological Evolution ; Selection, Genetic ; Models, Biological ; },
abstract = {AbstractThe widespread occurrence of genetically programmed cell death (PCD) in unicellular species poses an evolutionary puzzle. While kin selection theory predicts that the fitness benefits of cell suicide must be preferentially directed toward genetic relatives, it does not predict the nature of these benefits. Furthermore, cell suicide must be conditionally expressed, leaving open the question of what conditions optimally regulate expression. Here we formalize several verbal hypotheses for the ecological function of unicellular PCD. We show that self-sacrifice by healthy cells cannot evolve. Instead, PCD evolution requires that damaged cells sense impending death and then (1) expedite this death to spare resources for groupmates, (2) prepare cellular contents so that necrotic toxins are not released upon death, or initiate autolysis in order to (3) release beneficial compounds or (4) release anticompetitior toxins. The prerequisite ability to predict death is a severe cell biological constraint as well as an ecological constraint that restricts PCD evolution to species with specific sources of mortality. We show that the specific type of PCD that will evolve, though, differs on the basis of a species' ecology, life history, and genetic structure.},
}

*Apoptosis
*Biological Evolution
Selection, Genetic
Models, Biological

@article {pmid39485806,
year = {2024},
author = {},
title = {Correction for Green et al., Inclusive fitness consequences of dispersal decisions in a cooperatively breeding bird, the long-tailed tit (Aegithalos caudatus).},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {121},
number = {45},
pages = {e2419795121},
doi = {10.1073/pnas.2419795121},
pmid = {39485806},
issn = {1091-6490},
}

@article {pmid39471835,
year = {2024},
author = {Chokechaipaisarn, C and Gardner, A},
title = {Density-dependent dispersal reduces conflict over the sex ratio.},
journal = {Biology letters},
volume = {20},
number = {10},
pages = {20240378},
doi = {10.1098/rsbl.2024.0378},
pmid = {39471835},
issn = {1744-957X},
support = {//Queen Sirikit Scholarship/ ; /ERC_/European Research Council/International ; },
mesh = {*Sex Ratio ; Animals ; Male ; Female ; Population Density ; Animal Distribution ; Wasps/physiology ; Sexual Behavior, Animal ; Models, Biological ; },
abstract = {Haplodiploids-in particular, wasps-are the workhorses of sex-allocation research. This is owing to their unusual system of sex determination, which provides a ready means of sex ratio adjustment. Notably, their sexually asymmetrical mode of genetic inheritance leads mothers and fathers to come into conflict over the sex ratio of their offspring. In the simplest outbreeding scenario, a mother is favoured to employ an even sex ratio while a father prefers that all his mate's offspring are female. An important modulator of evolutionary conflict between mating partners is genetic relatedness, raising the possibility that this sex ratio conflict is reduced in low-dispersal settings with mating occurring between relatives. However, the impact of population viscosity on sex ratio conflict in haplodiploids remains unknown. Here, we develop and analyse a kin-selection model to investigate how the rate of dispersal modulates sex ratio conflict in a haplodiploid, viscous population setting. We find that population viscosity is associated with a reduction in the extent of sex ratio conflict-the effect being very weak under density-independent dispersal and much stronger under density-dependent dispersal.},
}

*Sex Ratio
Animals
Male
Female
Population Density
Animal Distribution
Wasps/physiology
Sexual Behavior, Animal
Models, Biological

@article {pmid39433392,
year = {2024},
author = {Patel, M and Arvid Ågren, J},
title = {Calculating Relatedness: A Pedigree of Definitions.},
journal = {Cold Spring Harbor perspectives in biology},
volume = {},
number = {},
pages = {},
doi = {10.1101/cshperspect.a041667},
pmid = {39433392},
issn = {1943-0264},
abstract = {Biology can be viewed from both an organismal and a genic perspective. A good example is W.D. Hamilton's work on inclusive fitness and kin selection, which puts relatedness at the heart of our understanding of social behavior. Relatedness mediates how much an actor should value a specific behavior's effect on a relative compared to the cost incurred to itself. Despite its key explanatory role, relatedness is also a concept marred with misunderstanding. Part of the problem has been that the term has been used in different ways by different people. To help address this, we survey the history of how relatedness has been formally modeled, paying particular attention to how it is conceptualized from both a gene-centric and an organism-centric point of view.},
}

@article {pmid39423260,
year = {2024},
author = {Updegrove, TB and Delerue, T and Anantharaman, V and Cho, H and Chan, C and Nipper, T and Choo-Wosoba, H and Jenkins, LM and Zhang, L and Su, Y and Shroff, H and Chen, J and Bewley, CA and Aravind, L and Ramamurthi, KS},
title = {Altruistic feeding and cell-cell signaling during bacterial differentiation actively enhance phenotypic heterogeneity.},
journal = {Science advances},
volume = {10},
number = {42},
pages = {eadq0791},
doi = {10.1126/sciadv.adq0791},
pmid = {39423260},
issn = {2375-2548},
mesh = {*Bacillus subtilis/physiology/metabolism/genetics ; *Spores, Bacterial/metabolism/growth & development ; *Signal Transduction ; *Bacterial Proteins/metabolism/genetics ; *Phenotype ; *Gene Expression Regulation, Bacterial ; Cell Communication ; },
abstract = {Starvation triggers bacterial spore formation, a committed differentiation program that transforms a vegetative cell into a dormant spore. Cells in a population enter sporulation nonuniformly to secure against the possibility that favorable growth conditions, which put sporulation-committed cells at a disadvantage, may resume. This heterogeneous behavior is initiated by a passive mechanism: stochastic activation of a master transcriptional regulator. Here, we identify a cell-cell communication pathway containing the proteins ShfA (YabQ) and ShfP (YvnB) that actively promotes phenotypic heterogeneity, wherein Bacillus subtilis cells that start sporulating early use a calcineurin-like phosphoesterase to release glycerol, which simultaneously acts as a signaling molecule and a nutrient to delay nonsporulating cells from entering sporulation. This produced a more diverse population that was better poised to exploit a sudden influx of nutrients compared to those generating heterogeneity via stochastic gene expression alone. Although conflict systems are prevalent among microbes, genetically encoded cooperative behavior in unicellular organisms can evidently also boost inclusive fitness.},
}

*Bacillus subtilis/physiology/metabolism/genetics
*Spores, Bacterial/metabolism/growth & development
*Signal Transduction
*Bacterial Proteins/metabolism/genetics
*Phenotype
*Gene Expression Regulation, Bacterial
Cell Communication

@article {pmid39398629,
year = {2024},
author = {Dentinger, JE and Dolan Todt, LA and Schultz, EA and Helferich, JN and Demarais, S and DeYoung, RW and McKinley, WT and Strickland, BK and Boudreau, MR},
title = {Testing secondary sex ratio bias hypotheses in white-tailed deer in Mississippi, USA.},
journal = {Ecology and evolution},
volume = {14},
number = {10},
pages = {e70296},
pmid = {39398629},
issn = {2045-7758},
abstract = {Natural selection favors individuals with the highest inclusive fitness (i.e., total number of descendants). In cases where one sex is more productive, one or both parents may maximize their inclusive fitness by investing in the offspring of the more prolific sex. Such preferential production can lead to skewed sex ratios at various life history stages, including at birth, resulting in secondary sex ratio bias. Several competing hypotheses have been proposed to explain observed variation in secondary sex ratios including Fisher's frequency dependence and two hypotheses related to maternal condition: Trivers-Willard and the local resource hypotheses. Although it has been shown that maternal condition can influence the number of offspring produced in white-tailed deer, there is no consensus as to which of the hypotheses drives sex ratio bias in wild populations. Using a spatiotemporally extensive dataset of pregnant white-tailed deer from Mississippi, USA, we examined fetal sex ratio in relation to the Fisherian frequency-dependence hypothesis and hypotheses related to maternal condition. While there was a male-sex ratio bias in pregnant females that reduced in intensity with the number of offspring, there was no support for condition-related hypotheses. Instead, secondary sex ratios for white-tailed deer in Mississippi were nearly consistent with Fisherian frequency dependence. Our findings add to the body of literature on secondary sex biases in white-tailed deer and help inform sex bias ratios for a southern population of a cervid of management importance in the US.},
}

@article {pmid39120521,
year = {2024},
author = {Fu, Y and Takeuchi, N},
title = {Evolution of the division of labour between templates and catalysts in spatial replicator models.},
journal = {Journal of evolutionary biology},
volume = {37},
number = {10},
pages = {1158-1169},
doi = {10.1093/jeb/voae098},
pmid = {39120521},
issn = {1420-9101},
support = {//University of Auckland/ ; //Digital Life Institute Seed Funding/ ; },
mesh = {*Biological Evolution ; Models, Biological ; Catalysis ; Models, Genetic ; },
abstract = {The central dogma of molecular biology can be conceptualised as the division of labour between templates and catalysts, where templates transmit genetic information, catalysts accelerate chemical reactions, and the information flows from templates to catalysts but not from catalysts to templates. How can template-catalyst division evolve in primordial replicating systems? A previous study has shown that even if the template-catalyst division does not provide an immediate fitness benefit, it can evolve through symmetry breaking between replicating molecules when the molecules are compartmentalised into protocells. However, cellular compartmentalisation may have been absent in primordial replicating systems. Here, we investigate whether cellular compartmentalisation is necessary for the evolution of the template-catalyst division via symmetry breaking using an individual-based model of replicators in a two-dimensional space. Our results show that replicators evolve the template-catalyst division via symmetry breaking when their diffusion constant is sufficiently high, a condition that results in low genetic relatedness between replicators. The evolution of the template-catalyst division reduces the risk of invasion by "cheaters," replicators that have no catalytic activities, encode no catalysts, but replicate to the detriment of local population growth. Our results suggest that the evolution of the template-catalyst division via symmetry breaking does not require cellular compartmentalization and is, instead, a general phenomenon in replicators with structured populations.},
}

*Biological Evolution
Models, Biological
Catalysis
Models, Genetic

@article {pmid39314835,
year = {2024},
author = {Dong, B and Paracchini, S and Gardner, A},
title = {Kin selection as a modulator of human handedness: sex-specific, parental and parent-of-origin effects.},
journal = {Evolutionary human sciences},
volume = {6},
number = {},
pages = {e32},
pmid = {39314835},
issn = {2513-843X},
abstract = {The frequency of left-handedness in humans is ~10% worldwide and slightly higher in males than females. Twin and family studies estimate the heritability of human handedness at around 25%. The low but substantial frequency of left-handedness has been suggested to imply negative frequency-dependent selection, e.g. owing to a 'surprise' advantage of left-handers in combat against opponents more used to fighting right-handers. Because such game-theoretic hypotheses involve social interaction, here we perform an analysis of the evolution of handedness based on kin-selection, which is understood to play a major role in the evolution of social behaviour generally. We show that: (1) relatedness modulates the balance of right-handedness vs. left-handedness, according to whether left-handedness is marginally selfish vs. marginally altruistic; (2) sex differences in relatedness to social partners may drive sex differences in handedness; (3) differential relatedness of parents and offspring may generate parent-offspring conflict and sexual conflict leading to the evolution of maternal and paternal genetic effects in relation to handedness; and (4) differential relatedness of maternal-origin vs. paternal-origin genes may generate intragenomic conflict leading to the evolution of parent-of-origin-specific gene effects - such as 'genomic imprinting' - and associated maladaptation.},
}

@article {pmid39255001,
year = {2024},
author = {Dos Santos, M and Downing, PA and Griffin, AS and Cornwallis, CK and West, SA},
title = {Altruism and natural selection in a variable environment.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {121},
number = {38},
pages = {e2402974121},
pmid = {39255001},
issn = {1091-6490},
support = {834164//EC | ERC | HORIZON EUROPE European Research Council (ERC)/ ; SESE//EC | ERC | HORIZON EUROPE European Research Council (ERC)/ ; WAF 2018.0138//Knut och Alice Wallenbergs Stiftelse (Knut and Alice Wallenberg Foundation)/ ; VR 2017-03880//Vetenskapsrådet (VR)/ ; },
mesh = {*Altruism ; Animals ; *Selection, Genetic ; *Birds/physiology ; Reproduction/physiology ; Biological Evolution ; Environment ; Behavior, Animal/physiology ; Social Behavior ; Cooperative Behavior ; Helping Behavior ; },
abstract = {Hamilton's rule provides the cornerstone for our understanding of the evolution of all forms of social behavior, from altruism to spite, across all organisms, from viruses to humans. In contrast to the standard prediction from Hamilton's rule, recent studies have suggested that altruistic helping can be favored even if it does not benefit relatives, as long as it decreases the environmentally induced variance of their reproductive success ("altruistic bet-hedging"). However, previous predictions both rely on an approximation and focus on variance-reducing helping behaviors. We derived a version of Hamilton's rule that fully captures environmental variability. This shows that decreasing (or increasing) the variance in the absolute reproductive success of relatives does not have a consistent effect-it can either favor or disfavor the evolution of helping. We then empirically quantified the effect of helping on the variance in reproductive success across 15 species of cooperatively breeding birds. We found that a) helping did not consistently decrease the variance of reproductive success and often increased it, and b) the mean benefits of helping across environments consistently outweighed other variability components of reproductive success. Altogether, our theoretical and empirical results suggest that the effects of helping on the variability components of reproductive success have not played a consistent or strong role in favoring helping.},
}

*Altruism
Animals
*Selection, Genetic
*Birds/physiology
Reproduction/physiology
Biological Evolution
Environment
Behavior, Animal/physiology
Social Behavior
Cooperative Behavior
Helping Behavior

@article {pmid39247287,
year = {2024},
author = {He, J and Zhao, Y and Chen, B and Bao, Y and Xiao, Z},
title = {Similarity enhances psychological compatibility: Serial mediation effect of psychological kinship and intergroup contact.},
journal = {Heliyon},
volume = {10},
number = {16},
pages = {e36262},
pmid = {39247287},
issn = {2405-8440},
abstract = {PURPOSE: This study elucidates the relationship between similarity and ethnic psychological compatibility and its underlying psychological mechanisms. According to kin selection theory, similarity can promote ethnic psychological compatibility by enhancing psychological kinship and intergroup contact.

PARTICIPANTS: and methods: A questionnaire survey was administered to 1523 participants from 25 ethnic groups in China. Data analysis was carried out via conditional process modelling. A multigroup comparison of mediation models between the ethnic majority and minorities was detected via the Stats Tools Package.

RESULTS: Our findings demonstrated that: (1) cultural and attitude similarity both showed a significant positive correlation with ethnic psychological compatibility; (2) psychological kinship and intergroup contact served as mediators in the relationship of attitude and cultural similarity with ethnic psychological compatibility and psychological kinship and intergroup contact were independent mediators, while psychological kinship-intergroup contact showed a significant serial mediation effect; (3) there were no significant differences in mediation effects between different ethnic groups.

CONCLUSION: Our findings expand on kin selection theory and provide valuable paths for psychologically supporting ethnic psychological compatibility.},
}

@article {pmid39182628,
year = {2024},
author = {Andersen, K and Rothausen, KW and Håberg, SE and Myrskylä, M and Ramlau-Hansen, CH and Gaml-Sørensen, A},
title = {Sibling relatedness and pubertal development in girls and boys: A population-based cohort study.},
journal = {Annals of epidemiology},
volume = {98},
number = {},
pages = {51-58},
doi = {10.1016/j.annepidem.2024.08.004},
pmid = {39182628},
issn = {1873-2585},
mesh = {Humans ; Male ; Female ; Denmark ; *Siblings/psychology ; *Puberty/psychology/physiology ; Child ; Adolescent ; Cohort Studies ; Sibling Relations ; },
abstract = {PURPOSE: To investigate the association between sibling relatedness and pubertal development in girls and boys.

METHODS: This cohort study consisted of 10,657 children from the Puberty Cohort, Denmark. Information on sibling relatedness was obtained by self-report. Information on pubertal markers was obtained half yearly from age 11 and throughout puberty. Mean age difference at attaining pubertal markers was estimated using interval-censored regression models according to sibling relatedness (full, half and/or step siblings; half and/or step siblings; no siblings; relative to full siblings).

RESULTS: Girls with both full, half and/or step siblings (-1.2 (CI 95 %: -2.5; 0.1) months), only half- and/or stepsiblings (-2.2 (CI 95 %: -3.7; -0.7) months), and no siblings (-5.5 (CI 95 %: -8.5; -2.5) months) entered puberty earlier than girls with full siblings. Boys with full, half and/or step siblings (-1.4 (CI 95 %: -2.7; -0.1) months), only half and/or step siblings (-1.2 (CI 95 %: -3.0; 0.6) months), and no siblings (-4.5 (CI 95 %: -8.8; -0.3) months) entered puberty earlier than boys with full siblings.

CONCLUSIONS: Children with sibling relatedness other than full siblings entered puberty earlier than their peers with full siblings even after adjustment for parental cohabitation status, childhood body mass index and childhood internalizing and externalizing symptoms.},
}

Humans
Male
Female
Denmark
*Siblings/psychology
*Puberty/psychology/physiology
Child
Adolescent
Cohort Studies
Sibling Relations

@article {pmid39152078,
year = {2024},
author = {Cremer, S and Pull, CD},
title = {Unconditional versus condition-dependent social immunity.},
journal = {Trends in parasitology},
volume = {40},
number = {9},
pages = {780-787},
doi = {10.1016/j.pt.2024.07.014},
pmid = {39152078},
issn = {1471-5007},
mesh = {Animals ; *Social Behavior ; Insecta/immunology/physiology ; Reproduction/immunology/physiology ; Behavior, Animal/physiology ; },
abstract = {Socially living animals can counteract disease through cooperative defences, leading to social immunity that collectively exceeds the sum of individual defences. In superorganismal colonies of social insects with permanent caste separation between reproductive queen(s) and nonreproducing workers, workers are obligate altruists and thus engage in unconditional social immunity, including highly specialised and self-sacrificial hygiene behaviours. Contrastingly, cooperation is facultative in cooperatively breeding families, where all members are reproductively totipotent but offspring transiently forgo reproduction to help their parents rear more siblings. Here, helpers should either express condition-dependent social immunity or disperse to pursue independent reproduction. We advocate inclusive fitness theory as a framework to predict when and how indirect fitness gains may outweigh direct fitness costs, thus favouring conditional social immunity.},
}

Animals
*Social Behavior
Insecta/immunology/physiology
Reproduction/immunology/physiology
Behavior, Animal/physiology

@article {pmid39110731,
year = {2024},
author = {Rees-Baylis, E and Pen, I and Kreider, JJ},
title = {Maternal manipulation of offspring size can trigger the evolution of eusociality in promiscuous species.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {121},
number = {33},
pages = {e2402179121},
pmid = {39110731},
issn = {1091-6490},
mesh = {Animals ; Female ; *Social Behavior ; *Biological Evolution ; *Body Size ; *Sexual Behavior, Animal/physiology ; *Reproduction/physiology ; Male ; Models, Biological ; Behavior, Animal/physiology ; },
abstract = {Eusocial organisms typically live in colonies with one reproductive queen supported by thousands of sterile workers. It is widely believed that monogamous mating is a precondition for the evolution of eusociality. Here, we present a theoretical model that simulates a realistic scenario for the evolution of eusociality. In the model, mothers can evolve control over resource allocation to offspring, affecting offspring's body size. The offspring can evolve body-size-dependent dispersal, by which they disperse to breed or stay at the nest as helpers. We demonstrate that eusociality can evolve even if mothers are not strictly monogamous, provided that they can constrain their offspring's reproduction through manipulation. We also observe the evolution of social polymorphism with small individuals that help and larger individuals that disperse to breed. Our model unifies the traditional kin selection and maternal manipulation explanations for the evolution of eusociality and demonstrates that-contrary to current consensus belief-eusociality can evolve despite highly promiscuous mating.},
}

Animals
Female
*Social Behavior
*Biological Evolution
*Body Size
*Sexual Behavior, Animal/physiology
*Reproduction/physiology
Male
Models, Biological
Behavior, Animal/physiology

@article {pmid38903092,
year = {2024},
author = {Updegrove, TB and Delerue, T and Anantharaman, V and Cho, H and Chan, C and Nipper, T and Choo-Wosoba, H and Jenkins, LM and Zhang, L and Su, Y and Shroff, H and Chen, J and Bewley, CA and Aravind, L and Ramamurthi, KS},
title = {Altruistic feeding and cell-cell signaling during bacterial differentiation actively enhance phenotypic heterogeneity.},
journal = {bioRxiv : the preprint server for biology},
volume = {},
number = {},
pages = {},
pmid = {38903092},
issn = {2692-8205},
abstract = {Starvation triggers bacterial spore formation, a committed differentiation program that transforms a vegetative cell into a dormant spore. Cells in a population enter sporulation non-uniformly to secure against the possibility that favorable growth conditions, which puts sporulation-committed cells at a disadvantage, may resume. This heterogeneous behavior is initiated by a passive mechanism: stochastic activation of a master transcriptional regulator. Here, we identify a cell-cell communication pathway that actively promotes phenotypic heterogeneity, wherein Bacillus subtilis cells that start sporulating early utilize a calcineurin-like phosphoesterase to release glycerol, which simultaneously acts as a signaling molecule and a nutrient to delay non-sporulating cells from entering sporulation. This produced a more diverse population that was better poised to exploit a sudden influx of nutrients compared to those generating heterogeneity via stochastic gene expression alone. Although conflict systems are prevalent among microbes, genetically encoded cooperative behavior in unicellular organisms can evidently also boost inclusive fitness.},
}

@article {pmid38842146,
year = {2024},
author = {Munasinghe, M and Brandvain, Y},
title = {Together Inbreeding and Reproductive Compensation Favor Lethal t-Haplotypes.},
journal = {The Journal of heredity},
volume = {},
number = {},
pages = {},
doi = {10.1093/jhered/esae030},
pmid = {38842146},
issn = {1465-7333},
abstract = {Male mice who are heterozygous for distorting and non-distorting alleles at the t-haplotype transmit the driving t-haplotype around 90% of the time - a drastic departure from Mendelian expectations. This selfish act comes at a cost. The mechanism underlying transmission distortion in this system causes severe sterility in males homozygous for the drive alleles, ultimately preventing its fixation. Curiously, many driving t-haplotypes also induce embryonic lethality in both sexes when homozygous; however, this is neither universal nor a necessity for this distortion mechanism. Charlesworth provided an adaptive explanation for the evolution of lethal t-haplotypes in a population segregating for distorting and non-distorting t alleles - if mothers compensate by replacing dead embryos with new offspring (or by transferring energy to surviving offspring), a recessive lethal can be favored because it effectively allows mothers the opportunity to trade in infertile males for potentially fertile offspring. This model, however, requires near complete reproductive compensation for the invasion of the lethal t-haplotype and produces an equilibrium frequency of lethal drivers well below what is observed in nature. We show that low levels of systemic inbreeding, which we model as brother-sister mating, allow lethal t-haplotypes to invade with much lower levels of reproductive compensation. Furthermore, inbreeding allows these lethal haplotypes to largely displace the ancestral male-sterile haplotypes. Our results show that together inbreeding and reproductive compensation move expected equilibria closer to observed haplotype frequencies in natural populations and occur under lower, potentially more reasonable, parameters.},
}

@article {pmid38818418,
year = {2024},
author = {Ferreira, HM and Alves, DA and Cool, L and Oi, CA and Oliveira, RC and Wenseleers, T},
title = {Toward greater realism in inclusive fitness models: the case of caste fate conflict in insect societies.},
journal = {Evolution letters},
volume = {8},
number = {3},
pages = {387-396},
pmid = {38818418},
issn = {2056-3744},
abstract = {In the field of social evolution, inclusive fitness theory has been successful in making a wide range of qualitative predictions on expected patterns of cooperation and conflict. Nevertheless, outside of sex ratio theory, inclusive fitness models that make accurate quantitative predictions remain relatively rare. Past models dealing with caste fate conflict in insect societies, for example, successfully predicted that if female larvae can control their own caste fate, an excess should opt to selfishly develop as queens. Available models, however, were unable to accurately predict levels of queen production observed in Melipona bees-a genus of stingless bees where caste is self-determined-as empirically observed levels of queen production are approximately two times lower than the theoretically predicted ones. Here, we show that this discrepancy can be resolved by explicitly deriving the colony-level cost of queen overproduction from a dynamic model of colony growth, requiring the incorporation of parameters of colony growth and demography, such as the per-capita rate at which new brood cells are built and provisioned, the percentage of the queen's eggs that are female, costs linked with worker reproduction and worker mortality. Our revised model predicts queen overproduction to more severely impact colony productivity, resulting in an evolutionarily stable strategy that is approximately half that of the original model, and is shown to accurately predict actual levels of queen overproduction observed in different Melipona species. Altogether, this shows how inclusive fitness models can provide accurate quantitative predictions, provided that costs and benefits are modeled in sufficient detail and are measured precisely.},
}

@article {pmid38785769,
year = {2024},
author = {Kuszewska, K and Woloszczuk, A and Woyciechowski, M},
title = {Reproductive Cessation and Post-Reproductive Lifespan in Honeybee Workers.},
journal = {Biology},
volume = {13},
number = {5},
pages = {},
pmid = {38785769},
issn = {2079-7737},
support = {2019/35/B/NZ8/00666//National Science Center/ ; DS/BiNoZ/INoŚ/761/10-14//Jagiellonian University/ ; },
abstract = {The post-reproductive lifespan is an evolutionary enigma because the cessation of reproduction in animals seems contrary to the maximization of Darwinian fitness. Several theories aim to explain the evolution of menopause, one of which suggests that females of a certain age receive more fitness benefits via indirect selection (kin selection) than they would directly from continuing reproduction. Post-reproductive lifespans are not very common in nature but have been described in humans, nonhuman primates, a few species of toothed whales, guppies, and in some insect societies consisting of clonal colony members, such as aphid and ant societies. Here, we provide evidence that menopause also exists in honeybee societies. Our study shows that workers with a short life expectancy (older and/or injured workers) invest fewer resources and less time in their own reproduction than workers with a long life expectancy (younger and/or uninjured workers), even if their colony is hopelessly queenless. These results are consistent with the kin selection explanation for the evolution of menopause and help us understand the net effects of relatedness and social cooperation in animals.},
}

@article {pmid38772422,
year = {2024},
author = {Walsman, JC and Lambe, M and Stephenson, JF},
title = {Associating with kin selects for disease resistance and against tolerance.},
journal = {Proceedings. Biological sciences},
volume = {291},
number = {2023},
pages = {20240356},
pmid = {38772422},
issn = {1471-2954},
mesh = {Animals ; *Poecilia/physiology/parasitology ; *Disease Resistance ; *Host-Parasite Interactions ; Fish Diseases/parasitology ; Biological Evolution ; Models, Biological ; },
abstract = {Behavioural and physiological resistance are key to slowing epidemic spread. We explore the evolutionary and epidemic consequences of their different costs for the evolution of tolerance that trades off with resistance. Behavioural resistance affects social cohesion, with associated group-level costs, while the cost of physiological resistance accrues only to the individual. Further, resistance, and the associated reduction in transmission, benefit susceptible hosts directly, whereas infected hosts only benefit indirectly, by reducing transmission to kin. We therefore model the coevolution of transmission-reducing resistance expressed in susceptible hosts with resistance expressed in infected hosts, as a function of kin association, and analyse the effect on population-level outcomes. Using parameter values for guppies, Poecilia reticulata, and their gyrodactylid parasites, we find that: (1) either susceptible or infected hosts should invest heavily in resistance, but not both; (2) kin association drives investment in physiological resistance more strongly than in behavioural resistance; and (3) even weak levels of kin association can favour altruistic infected hosts that invest heavily in resistance (versus selfish tolerance), eliminating parasites. Overall, our finding that weak kin association affects the coevolution of infected and susceptible investment in both behavioural and physiological resistance suggests that kin selection may affect disease dynamics across systems.},
}

Animals
*Poecilia/physiology/parasitology
*Disease Resistance
*Host-Parasite Interactions
Fish Diseases/parasitology
Biological Evolution
Models, Biological

@article {pmid38713735,
year = {2024},
author = {Oszoli, I and Zachar, I},
title = {Group-selection via aggregative propagule-formation enables cooperative multicellularity in an individual based, spatial model.},
journal = {PLoS computational biology},
volume = {20},
number = {5},
pages = {e1012107},
pmid = {38713735},
issn = {1553-7358},
mesh = {*Models, Biological ; *Biological Evolution ; Computational Biology ; Ecosystem ; Animals ; Predatory Behavior/physiology ; Selection, Genetic ; Computer Simulation ; },
abstract = {The emergence of multicellularity is one of the major transitions in evolution that happened multiple times independently. During aggregative multicellularity, genetically potentially unrelated lineages cooperate to form transient multicellular groups. Unlike clonal multicellularity, aggregative multicellular organisms do not rely on kin selection instead other mechanisms maintain cooperation against cheater phenotypes that benefit from cooperators but do not contribute to groups. Spatiality with limited diffusion can facilitate group selection, as interactions among individuals are restricted to local neighbourhoods only. Selection for larger size (e.g. avoiding predation) may facilitate the emergence of aggregation, though it is unknown, whether and how much role such selection played during the evolution of aggregative multicellularity. We have investigated the effect of spatiality and the necessity of predation on the stability of aggregative multicellularity via individual-based modelling on the ecological timescale. We have examined whether aggregation facilitates the survival of cooperators in a temporally heterogeneous environment against cheaters, where only a subset of the population is allowed to periodically colonize a new, resource-rich habitat. Cooperators constitutively produce adhesive molecules to promote aggregation and propagule-formation while cheaters spare this expense to grow faster but cannot aggregate on their own, hence depending on cooperators for long-term survival. We have compared different population-level reproduction modes with and without individual selection (predation) to evaluate the different hypotheses. In a temporally homogeneous environment without propagule-based colonization, cheaters always win. Predation can benefit cooperators, but it is not enough to maintain the necessary cooperator amount in successive dispersals, either randomly or by fragmentation. Aggregation-based propagation however can ensure the adequate ratio of cooperators-to-cheaters in the propagule and is sufficient to do so even without predation. Spatiality combined with temporal heterogeneity helps cooperators via group selection, thus facilitating aggregative multicellularity. External stress selecting for larger size (e.g. predation) may facilitate aggregation, however, according to our results, it is neither necessary nor sufficient for aggregative multicellularity to be maintained when there is effective group-selection.},
}

*Models, Biological
*Biological Evolution
Computational Biology
Ecosystem
Animals
Predatory Behavior/physiology
Selection, Genetic
Computer Simulation

@article {pmid38659681,
year = {2024},
author = {Andersen, S},
title = {The maps of meaning consciousness theory.},
journal = {Frontiers in psychology},
volume = {15},
number = {},
pages = {1161132},
pmid = {38659681},
issn = {1664-1078},
abstract = {In simple terms, consciousness is constituted by multiple goals for action and the continuous adjudication of such goals to implement action, which is referred to as the maps of meaning (MoM) consciousness theory. The MoM theory triangulates through three parallel corollaries: action (behavior), mechanism (morphology/pathophysiology), and goals (teleology). (1) An organism's consciousness contains fluid, nested goals. These goals are not intentionality, but intersectionality, via the Darwinian byproduct of embodiment meeting the world, i.e., Darwinian inclusive fitness or randomization and then survival of the fittest. (2) These goals are formed via a gradual descent under inclusive fitness and are the abstraction of a "match" between the evolutionary environment and the organism. (3) Human consciousness implements the brain efficiency hypothesis, genetics, epigenetics, and experience-crystallized efficiencies, not necessitating best or objective but fitness, i.e., perceived efficiency based on one's adaptive environment. These efficiencies are objectively arbitrary but determine the operation and level of one's consciousness, termed as extreme thrownness. (4) Since inclusive fitness drives efficiencies in the physiologic mechanism, morphology, and behavior (action) and originates one's goals, embodiment is necessarily entangled to human consciousness as it is at the intersection of mechanism or action (both necessitating embodiment) occurring in the world that determines fitness. (5) Perception is the operant process of consciousness and is the de facto goal adjudication process of consciousness. Goal operationalization is fundamentally efficiency-based via one's unique neuronal mapping as a byproduct of genetics, epigenetics, and experience. (6) Perception involves information intake and information discrimination, equally underpinned by efficiencies of inclusive fitness via extreme thrownness. Perception is not a 'frame rate' but Bayesian priors of efficiency based on one's extreme thrownness. (7) Consciousness and human consciousness are modular (i.e., a scalar level of richness, which builds up like building blocks) and dimensionalized (i.e., cognitive abilities become possibilities as the emergent phenomena at various modularities such as the stratified factors in factor analysis). (8) The meta dimensions of human consciousness seemingly include intelligence quotient, personality (five-factor model), richness of perception intake, and richness of perception discrimination, among other potentialities. (9) Future consciousness research should utilize factor analysis to parse modularities and dimensions of human consciousness and animal models.},
}

@article {pmid38657758,
year = {2024},
author = {Kobayashi, Y and Ueno, M},
title = {Proximity and preening in captive Humboldt penguins.},
journal = {Behavioural processes},
volume = {218},
number = {},
pages = {105032},
doi = {10.1016/j.beproc.2024.105032},
pmid = {38657758},
issn = {1872-8308},
mesh = {Animals ; *Spheniscidae/physiology ; *Social Behavior ; *Grooming/physiology ; Male ; *Animals, Zoo ; Female ; Behavior, Animal/physiology ; },
abstract = {Group-living animals, including penguins, exhibit affiliative behaviors such as grooming (preening) and proximity. Such behaviors in non-primate animals have been less studied than those in primates. Our research focused on 20 identifiable Humboldt penguins in a zoo, analyzing kin relationships and reciprocity in preening and proximity by employing a 5-minute scan sampling method to observe and record individual behavior. Our findings revealed that preening and proximity were more prevalent among mate pairs. However, among non-mate pairs, such behaviors were more commonly observed between siblings and parent-offspring pairs. Notably, the individuals preened on each other simultaneously in all instances. This study highlights the potential influence of kin selection in shaping the affiliative behavior of penguins. Additionally, our findings indicate that penguins gain benefits from mutual preening. This study contributes to our understanding of social behaviors in non-primate species and emphasizes the need for further comparative studies of various animal taxa to elucidate the evolution of sociality.},
}

Animals
*Spheniscidae/physiology
*Social Behavior
*Grooming/physiology
Male
*Animals, Zoo
Female
Behavior, Animal/physiology

@article {pmid38577983,
year = {2024},
author = {West, SA and Griffin, AS},
title = {Microbial Primer: Cooperation in bacteria.},
journal = {Microbiology (Reading, England)},
volume = {170},
number = {4},
pages = {},
doi = {10.1099/mic.0.001440},
pmid = {38577983},
issn = {1465-2080},
mesh = {*Cooperative Behavior ; *Altruism ; Biological Evolution ; Bacteria/genetics ; },
abstract = {The growth and success of many bacteria appear to rely on a stunning range of cooperative behaviours. But what is cooperation and how is it studied?},
}

*Cooperative Behavior
*Altruism
Biological Evolution
Bacteria/genetics

@article {pmid38560219,
year = {2024},
author = {Yang, J and Wang, Y and El Wakil, A and Moussian, B},
title = {Extra-corporeal detoxification in insects.},
journal = {Heliyon},
volume = {10},
number = {7},
pages = {e28392},
pmid = {38560219},
issn = {2405-8440},
abstract = {Upon uptake of toxins, insects launch a detoxification program. This program is deployed in multiple organs and cells to raise their tolerance against the toxin. The molecular mechanisms of this program inside the insect body have been studied and understood in detail. Here, we report on a yet unexplored extra-corporeal detoxification of insecticides in Drosophila melanogaster. Wild-type D. melanogaster incubated with DDT, a contact insecticide, in a closed environment died as expected. However, incubation of a second cohort in the same environment after removal of the dead flies was not lethal. The effect was significantly lower if the flies of the two cohorts were unrelated. Incubation assays with Chlorpyrifos, another contact insecticide, yielded identical results, while incubation assays with Chlorantraniliprole, again a contact insecticide, was toxic for the second cohort of flies. A cohort of flies incubated in a DDT environment after an initial incubation of a honeybee survived treatment. Together, our data suggest that insects including Apis mellifera and D. melanogaster have the capacity to modify their proximate environment. Consequently, in their ecological niche, following individuals might be saved from intoxication thereby facilitating colonisation of an attractive site.},
}

@article {pmid38492917,
year = {2024},
author = {McGrane-Corrigan, B and Mason, O and de Andrade Moral, R},
title = {Inferring stochastic group interactions within structured populations via coupled autoregression.},
journal = {Journal of theoretical biology},
volume = {584},
number = {},
pages = {111793},
doi = {10.1016/j.jtbi.2024.111793},
pmid = {38492917},
issn = {1095-8541},
mesh = {Animals ; *Ecosystem ; Population Dynamics ; Bayes Theorem ; *Predatory Behavior ; Models, Biological ; Group Dynamics ; Food Chain ; },
abstract = {The internal behaviour of a population is an important feature to take account of when modelling its dynamics. In line with kin selection theory, many social species tend to cluster into distinct groups in order to enhance their overall population fitness. Temporal interactions between populations are often modelled using classical mathematical models, but these sometimes fail to delve deeper into the, often uncertain, relationships within populations. Here, we introduce a stochastic framework that aims to capture the interactions of animal groups and an auxiliary population over time. We demonstrate the model's capabilities, from a Bayesian perspective, through simulation studies and by fitting it to predator-prey count time series data. We then derive an approximation to the group correlation structure within such a population, while also taking account of the effect of the auxiliary population. We finally discuss how this approximation can lead to ecologically realistic interpretations in a predator-prey context. This approximation also serves as verification to whether the population in question satisfies our various assumptions. Our modelling approach will be useful for empiricists for monitoring groups within a conservation framework and also theoreticians wanting to quantify interactions, to study cooperation and other phenomena within social populations.},
}

Animals
*Ecosystem
Population Dynamics
Bayes Theorem
*Predatory Behavior
Models, Biological
Group Dynamics
Food Chain

@article {pmid38477032,
year = {2024},
author = {Fromhage, L and Jennions, MD and Myllymaa, L and Henshaw, JM},
title = {Fitness as the organismal performance measure guiding adaptive evolution.},
journal = {Evolution; international journal of organic evolution},
volume = {78},
number = {6},
pages = {1039-1053},
doi = {10.1093/evolut/qpae043},
pmid = {38477032},
issn = {1558-5646},
support = {456626331//Bundesministerium für Bildung und Forschung and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)/ ; 340130//Research Council of Finland/ ; },
mesh = {*Genetic Fitness ; *Selection, Genetic ; *Biological Evolution ; Adaptation, Biological ; Animals ; Models, Genetic ; Phenotype ; Adaptation, Physiological/genetics ; },
abstract = {A long-standing problem in evolutionary theory is to clarify in what sense (if any) natural selection cumulatively improves the design of organisms. Various concepts, such as fitness and inclusive fitness, have been proposed to resolve this problem. In addition, there have been attempts to replace the original problem with more tractable questions, such as whether a given gene or trait is favored by selection. Here, we ask what theoretical properties the concept fitness should possess to encapsulate the improvement criterion required to talk meaningfully about adaptive evolution. We argue that natural selection tends to shape phenotypes based on the causal properties of individuals and that this tendency is, therefore, best captured by a fitness concept that focuses on these properties. We highlight a fitness concept that meets this role under broad conditions but requires adjustments in our conceptual understanding of adaptive evolution. These adjustments combine elements of Dawkinsian gene selectionism and Egbert Leigh's "parliament of genes."},
}

*Genetic Fitness
*Selection, Genetic
*Biological Evolution
Adaptation, Biological
Animals
Models, Genetic
Phenotype
Adaptation, Physiological/genetics

@article {pmid38471475,
year = {2024},
author = {Schradin, C and Jaeggi, AV and Criscuolo, F},
title = {Quick Guide to Evolutionary Medicine in Neuroimmunomodulation: Why "Evolved for the Benefit of the Species" Is Not a Valid Argument.},
journal = {Neuroimmunomodulation},
volume = {31},
number = {1},
pages = {66-77},
doi = {10.1159/000538294},
pmid = {38471475},
issn = {1423-0216},
mesh = {Humans ; *Biological Evolution ; *Neuroimmunomodulation/physiology ; Animals ; Phylogeny ; Selection, Genetic ; },
abstract = {BACKGROUND: Evolutionary medicine builds on evolutionary biology and explains why natural selection has left us vulnerable to disease. Unfortunately, several misunderstandings exist in the medical literature about the levels and mechanisms of evolution. Reasons for these problems start from the lack of teaching evolutionary biology in medical schools. A common mistake is to assume that "traits must benefit the species, as otherwise the species would have gone extinct in the past" confusing evolutionary history (phylogeny) with evolutionary function (fitness).

SUMMARY: Here we summarise some basic aspects of evolutionary medicine by pointing out: (1) Evolution has no aim. (2) For adaptive evolution to occur, a trait does not have to be beneficial to its carrier throughout its entire life. (3) Not every single individual carrying an adaptive trait needs to have higher than average fitness. (4) Traits do not evolve for the benefit of the species. Using examples from the field of neuroimmunomodulation like sickness behaviour (nervous system), testosterone (hormones), and cytokines (immunity), we show how misconceptions arise from not differentiating between the explanatory categories of phylogeny (evolutionary history) and evolutionary function (fitness).

KEY MESSAGES: Evolution has no aim but is an automatism that does not function for the benefit of the species. In evolution, successful individuals are those that maximise the transmission of their genes, and health and survival are just strategies to have the opportunity to do so. Thus, a trait enabling survival of the individual until reproductive age will spread even if at later age the same trait leads to disease and death. Natural and sexual selection do not select for traits that benefit the health or happiness of the individual, but for traits that increase inclusive fitness even if this increases human suffering. In contrast, our humane aim is to increase individual well-being. Evolutionary medicine can help us achieve this aim against evolutionary constraints.},
}

Humans
*Biological Evolution
*Neuroimmunomodulation/physiology
Animals
Phylogeny
Selection, Genetic

@article {pmid38462458,
year = {2023},
author = {Libertini, G},
title = {Phenoptosis and the Various Types of Natural Selection.},
journal = {Biochemistry. Biokhimiia},
volume = {88},
number = {12},
pages = {2007-2022},
doi = {10.1134/S0006297923120052},
pmid = {38462458},
issn = {1608-3040},
mesh = {Animals ; Bees ; *Aging/genetics ; Ecosystem ; Selection, Genetic ; *Ants ; Reproduction ; Biological Evolution ; },
abstract = {In the first description of evolution, the fundamental mechanism is the natural selection favoring the individuals best suited for survival and reproduction (selection at the individual level or classical Darwinian selection). However, this is a very reductive description of natural selection that does not consider or explain a long series of known phenomena, including those in which an individual sacrifices or jeopardizes his life on the basis of genetically determined mechanisms (i.e., phenoptosis). In fact, in addition to (i) selection at the individual level, it is essential to consider other types of natural selection such as those concerning: (ii) kin selection and some related forms of group selection; (iii) the interactions between the innumerable species that constitute a holobiont; (iv) the origin of the eukaryotic cell from prokaryotic organisms; (v) the origin of multicellular eukaryotic organisms from unicellular organisms; (vi) eusociality (e.g., in many species of ants, bees, termites); (vii) selection at the level of single genes, or groups of genes; (viii) the interactions between individuals (or more precisely their holobionts) of the innumerable species that make up an ecosystem. These forms of natural selection, which are all effects and not violations of the classical Darwinian selection, also show how concepts as life, species, individual, and phenoptosis are somewhat not entirely defined and somehow arbitrary. Furthermore, the idea of organisms selected on the basis of their survival and reproduction capabilities is intertwined with that of organisms also selected on the basis of their ability to cooperate and interact, even by losing their lives or their distinct identities.},
}

Animals
Bees
*Aging/genetics
Ecosystem
Selection, Genetic
*Ants
Reproduction
Biological Evolution

@article {pmid38443305,
year = {2024},
author = {Erler, S and Cotter, SC and Freitak, D and Koch, H and Palmer-Young, EC and de Roode, JC and Smilanich, AM and Lattorff, HMG},
title = {Insects' essential role in understanding and broadening animal medication.},
journal = {Trends in parasitology},
volume = {40},
number = {4},
pages = {338-349},
doi = {10.1016/j.pt.2024.02.003},
pmid = {38443305},
issn = {1471-5007},
mesh = {Animals ; Humans ; *Insecta ; *Parasites ; Reproduction ; Host-Parasite Interactions ; },
abstract = {Like humans, animals use plants and other materials as medication against parasites. Recent decades have shown that the study of insects can greatly advance our understanding of medication behaviors. The ease of rearing insects under laboratory conditions has enabled controlled experiments to test critical hypotheses, while their spectrum of reproductive strategies and living arrangements - ranging from solitary to eusocial communities - has revealed that medication behaviors can evolve to maximize inclusive fitness through both direct and indirect fitness benefits. Studying insects has also demonstrated in some cases that medication can act through modulation of the host's innate immune system and microbiome. We highlight outstanding questions, focusing on costs and benefits in the context of inclusive host fitness.},
}

Animals
Humans
*Insecta
*Parasites
Reproduction
Host-Parasite Interactions

@article {pmid38420213,
year = {2024},
author = {Kemp, JT and Kline, AG and Bettencourt, LMA},
title = {Information synergy maximizes the growth rate of heterogeneous groups.},
journal = {PNAS nexus},
volume = {3},
number = {2},
pages = {pgae072},
pmid = {38420213},
issn = {2752-6542},
support = {R01 EB026943/EB/NIBIB NIH HHS/United States ; },
abstract = {Collective action and group formation are fundamental behaviors among both organisms cooperating to maximize their fitness and people forming socioeconomic organizations. Researchers have extensively explored social interaction structures via game theory and homophilic linkages, such as kin selection and scalar stress, to understand emergent cooperation in complex systems. However, we still lack a general theory capable of predicting how agents benefit from heterogeneous preferences, joint information, or skill complementarities in statistical environments. Here, we derive general statistical dynamics for the origin of cooperation based on the management of resources and pooled information. Specifically, we show how groups that optimally combine complementary agent knowledge about resources in statistical environments maximize their growth rate. We show that these advantages are quantified by the information synergy embedded in the conditional probability of environmental states given agents' signals, such that groups with a greater diversity of signals maximize their collective information. It follows that, when constraints are placed on group formation, agents must intelligently select with whom they cooperate to maximize the synergy available to their own signal. Our results show how the general properties of information underlie the optimal collective formation and dynamics of groups of heterogeneous agents across social and biological phenomena.},
}

@article {pmid38417560,
year = {2024},
author = {Flatrès, A and Wild, G},
title = {Evolution of delayed dispersal with group size effect and population dynamics.},
journal = {Theoretical population biology},
volume = {157},
number = {},
pages = {1-13},
doi = {10.1016/j.tpb.2024.02.007},
pmid = {38417560},
issn = {1096-0325},
mesh = {*Population Dynamics ; Animals ; Biological Evolution ; Population Density ; Fertility ; Social Behavior ; Reproduction ; },
abstract = {Individuals delay natal dispersal for many reasons. There may be no place to disperse to; immediate dispersal or reproduction may be too costly; immediate dispersal may mean that the individual and their relatives miss the benefits of group living. Understanding the factors that lead to the evolution of delayed dispersal is important because delayed dispersal sets the stage for complex social groups and social behavior. Here, we study the evolution of delayed dispersal when the quality of the local environment is improved by greater numbers of individuals (e.g., safety in numbers). We assume that individuals who delay natal dispersal also expect to delay personal reproduction. In addition, we assume that improved environmental quality benefits manifest as changes to fecundity and survival. We are interested in how do the changes in these life-history features affect delayed dispersal. We use a model that ties evolution to population dynamics. We also aim to understand the relationship between levels of delayed dispersal and the probability of establishing as an independent breeder (a population-level feature) in response to changes in life-history details. Our model emphasizes kin selection and considers a sexual organism, which allows us to study parent-offspring conflict over delayed dispersal. At evolutionary equilibrium, fecundity and survival benefits of group size or quality promote higher levels of delayed dispersal over a larger set of life histories with one exception. The exception is for benefits of increased group size or quality reaped by the individuals who delay dispersal. There, the increased benefit does not change the life histories supporting delay dispersal. Next, in contrast to previous predictions, we find that a low probability of establishing in a new location is not always associated with a higher incidence of delayed dispersal. Finally, we find that increased personal benefits of delayed dispersal exacerbate the conflict between parents and their offspring. We discuss our findings in relation to previous theoretical and empirical work, especially work related to cooperative breeding.},
}

*Population Dynamics
Animals
Biological Evolution
Population Density
Fertility
Social Behavior
Reproduction

@article {pmid38412971,
year = {2024},
author = {Dewar, AE and Belcher, LJ and Scott, TW and West, SA},
title = {Genes for cooperation are not more likely to be carried by plasmids.},
journal = {Proceedings. Biological sciences},
volume = {291},
number = {2017},
pages = {20232549},
pmid = {38412971},
issn = {1471-2954},
mesh = {Plasmids/genetics ; *Genome, Bacterial ; *Bacteria/genetics ; Genomics ; Gene Transfer, Horizontal ; },
abstract = {Cooperation is prevalent across bacteria, but risks being exploited by non-cooperative cheats. Horizontal gene transfer, particularly via plasmids, has been suggested as a mechanism to stabilize cooperation. A key prediction of this hypothesis is that genes which are more likely to be transferred, such as those on plasmids, should be more likely to code for cooperative traits. Testing this prediction requires identifying all genes for cooperation in bacterial genomes. However, previous studies used a method which likely misses some of these genes for cooperation. To solve this, we used a new genomics tool, SOCfinder, which uses three distinct modules to identify all kinds of genes for cooperation. We compared where these genes were located across 4648 genomes from 146 bacterial species. In contrast to the prediction of the hypothesis, we found no evidence that plasmid genes are more likely to code for cooperative traits. Instead, we found the opposite-that genes for cooperation were more likely to be carried on chromosomes. Overall, the vast majority of genes for cooperation are not located on plasmids, suggesting that the more general mechanism of kin selection is sufficient to explain the prevalence of cooperation across bacteria.},
}

Plasmids/genetics
*Genome, Bacterial
*Bacteria/genetics
Genomics
Gene Transfer, Horizontal

@article {pmid38409256,
year = {2024},
author = {Galdino, ACM and Vaillancourt, M and Celedonio, D and Huse, K and Doi, Y and Lee, JS and Jorth, P},
title = {Siderophores promote cooperative interspecies and intraspecies cross-protection against antibiotics in vitro.},
journal = {Nature microbiology},
volume = {9},
number = {3},
pages = {631-646},
pmid = {38409256},
issn = {2058-5276},
support = {JORTH19P0//Cystic Fibrosis Foundation (CF Foundation)/ ; K22 AI127473/AI/NIAID NIH HHS/United States ; R01 AI146425/AI/NIAID NIH HHS/United States ; R01Hl136143//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; R01 HL136143/HL/NHLBI NIH HHS/United States ; R01AI14642//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; R21 AI151362/AI/NIAID NIH HHS/United States ; JORTH17F5//Cystic Fibrosis Foundation (CF Foundation)/ ; MILESI21F0//Cystic Fibrosis Foundation (CF Foundation)/ ; R21AI151362//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; K22AI127473//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; },
mesh = {Humans ; *Anti-Bacterial Agents/pharmacology/metabolism ; *Siderophores/metabolism/pharmacology ; Cefiderocol ; Iron/metabolism ; Enterobacteriaceae/metabolism ; Pseudomonas aeruginosa/metabolism ; },
abstract = {The antibiotic cefiderocol hijacks iron transporters to facilitate its uptake and resists β-lactamase degradation. While effective, resistance has been detected clinically with unknown mechanisms. Here, using experimental evolution, we identified cefiderocol resistance mutations in Pseudomonas aeruginosa. Resistance was multifactorial in host-mimicking growth media, led to multidrug resistance and paid fitness costs in cefiderocol-free environments. However, kin selection drove some resistant populations to cross-protect susceptible individuals from killing by increasing pyoverdine secretion via a two-component sensor mutation. While pyochelin sensitized P. aeruginosa to cefiderocol killing, pyoverdine and the enterobacteria siderophore enterobactin displaced iron from cefiderocol, preventing uptake by susceptible cells. Among 113 P. aeruginosa intensive care unit clinical isolates, pyoverdine production directly correlated with cefiderocol tolerance, and high pyoverdine producing isolates cross-protected susceptible P. aeruginosa and other Gram-negative bacteria. These in vitro data show that antibiotic cross-protection can occur via degradation-independent mechanisms and siderophores can serve unexpected protective cooperative roles in polymicrobial communities.},
}

Humans
*Anti-Bacterial Agents/pharmacology/metabolism
*Siderophores/metabolism/pharmacology
Cefiderocol
Iron/metabolism
Enterobacteriaceae/metabolism
Pseudomonas aeruginosa/metabolism

@article {pmid38403933,
year = {2024},
author = {Montazeaud, G and Keller, L},
title = {Greenbeards in plants?.},
journal = {The New phytologist},
volume = {242},
number = {3},
pages = {870-877},
doi = {10.1111/nph.19599},
pmid = {38403933},
issn = {1469-8137},
support = {101030712//HORIZON EUROPE Marie Sklodowska-Curie Actions/ ; },
abstract = {Greenbeards are selfish genetic elements that make their bearers behave either altruistically towards individuals bearing similar greenbeard copies or harmfully towards individuals bearing different copies. They were first proposed by W. D. Hamilton over 50 yr ago, to illustrate that kin selection may operate at the level of single genes. Examples of greenbeards have now been reported in a wide range of taxa, but they remain undocumented in plants. In this paper, we discuss the theoretical likelihood of greenbeard existence in plants. We then question why the greenbeard concept has never been applied to plants and speculate on how hypothetical greenbeards could affect plant-plant interactions. Finally, we point to different research directions to improve our knowledge of greenbeards in plants.},
}

@article {pmid38371869,
year = {2024},
author = {Thomson, L and Espinosa, DP and Brandvain, Y and Van Cleve, J},
title = {Linked selection and the evolution of altruism in family-structured populations.},
journal = {Ecology and evolution},
volume = {14},
number = {2},
pages = {e10980},
pmid = {38371869},
issn = {2045-7758},
abstract = {Much research on the evolution of altruism via kin selection, group selection, and reciprocity focuses on the role of a single locus or quantitative trait. Very few studies have explored how linked selection, or selection at loci neighboring an altruism locus, impacts the evolution of altruism. While linked selection can decrease the efficacy of selection at neighboring loci, it might have other effects including promoting selection for altruism by increasing relatedness in regions of low recombination. Here, we used population genetic simulations to study how negative selection at linked loci, or background selection, affects the evolution of altruism. When altruism occurs between full siblings, we found that background selection interfered with selection on the altruistic allele, increasing its fixation probability when the altruistic allele was disfavored and reducing its fixation when the allele was favored. In other words, background selection has the same effect on altruistic genes in family-structured populations as it does on other, nonsocial, genes. This contrasts with prior research showing that linked selective sweeps can favor the evolution of cooperation, and we discuss possibilities for resolving these contrasting results.},
}

@article {pmid38368855,
year = {2024},
author = {Crespi, BJ},
title = {The Roots of Science, Technology, Engineering, and Mathematics: What Are the Evolutionary and Neural Bases of Human Mathematics and Technology?.},
journal = {Brain, behavior and evolution},
volume = {99},
number = {1},
pages = {1-12},
doi = {10.1159/000537908},
pmid = {38368855},
issn = {1421-9743},
mesh = {Animals ; Humans ; Biological Evolution ; *Brain/physiology/anatomy & histology ; Cognition/physiology ; *Engineering ; *Mathematics ; *Science ; *Technology ; },
abstract = {INTRODUCTION: Neural exaptations represent descent via transitions to novel neural functions. A primary transition in human cognitive and neural evolution was from a predominantly socially oriented primate brain to a brain that also instantiates and subserves science, technology, and engineering, all of which depend on mathematics. Upon what neural substrates and upon what evolved cognitive mechanisms did human capacities for science, technology, engineering, and mathematics (STEM), and especially its mathematical underpinnings, emerge? Previous theory focuses on roles for tools, language, and arithmetic in the cognitive origins of STEM, but none of these factors appears sufficient to support the transition.

METHODS: In this article, I describe and evaluate a novel hypothesis for the neural origins and substrates of STEM-based cognition: that they are based in human kinship systems and human maximizing of inclusive fitness.

RESULTS: The main evidence for this hypothesis is threefold. First, as demonstrated by anthropologists, human kinship systems exhibit complex mathematical and geometrical structures that function under sets of explicit rules, and such systems and rules pervade and organize all human cultures. Second, human kinship underlies the core algebraic mechanism of evolution, maximization of inclusive fitness, quantified as personal reproduction plus the sum of all effects on reproduction of others, each multiplied by their coefficient of relatedness to self. This is the only "natural" equation expected to be represented in the human brain. Third, functional imaging studies show that kinship-related cognition activates frontal-parietal regions that are also activated in STEM-related tasks. In turn, the decision-making that integrates kinship levels with costs and benefits from alternative behaviors has recently been shown to recruit the lateral septum, a hub region that combines internal (from the prefrontal cortex, amygdala, and other regions) and external information relevant to social behavior, using a dedicated subsystem of neurons specific to kinship.

CONCLUSIONS: Taken together, these lines of evidence suggest that kinship systems and kin-associated behaviors may represent exaptations for the origin of human STEM.},
}

Animals
Humans
Biological Evolution
*Brain/physiology/anatomy & histology
Cognition/physiology
*Engineering
*Mathematics
*Science
*Technology

@article {pmid38358814,
year = {2024},
author = {Kerr, NZ and Morris, WF and Walters, JR},
title = {Inclusive Fitness May Explain Some but Not All Benefits Derived from Helping Behavior in a Cooperatively Breeding Bird.},
journal = {The American naturalist},
volume = {203},
number = {3},
pages = {393-410},
doi = {10.1086/728670},
pmid = {38358814},
issn = {1537-5323},
mesh = {Animals ; Male ; *Helping Behavior ; *Cooperative Behavior ; Birds ; Reproduction ; },
abstract = {AbstractIn cooperative breeding systems, inclusive fitness theory predicts that nonbreeding helpers more closely related to the breeders should be more willing to provide costly alloparental care and thus have more impact on breeder fitness. In the red-cockaded woodpecker (Dryobates borealis), most helpers are the breeders' earlier offspring, but helpers do vary within groups in both relatedness to the breeders (some even being unrelated) and sex, and it can be difficult to parse their separate impacts on breeder fitness. Moreover, most support for inclusive fitness theory has been positive associations between relatedness and behavior rather than actual fitness consequences. We used functional linear models to evaluate the per capita effects of helpers of different relatedness on eight breeder fitness components measured for up to 41 years at three sites. In support of inclusive fitness theory, helpers more related to the breeding pair made greater contributions to six fitness components. However, male helpers made equal contributions to increasing prefledging survival regardless of relatedness. These findings suggest that both inclusive fitness benefits and other direct benefits may underlie helping behaviors in the red-cockaded woodpecker. Our results also demonstrate the application of an underused statistical approach to disentangle a complex ecological phenomenon.},
}

Animals
Male
*Helping Behavior
*Cooperative Behavior
Birds
Reproduction

@article {pmid38353866,
year = {2024},
author = {Waynforth, D},
title = {Alloparental Support and Infant Psychomotor Developmental Delay.},
journal = {Human nature (Hawthorne, N.Y.)},
volume = {35},
number = {1},
pages = {43-62},
pmid = {38353866},
issn = {1936-4776},
mesh = {Humans ; Infant ; *Developmental Disabilities ; Female ; *Social Support ; Male ; United Kingdom ; Mothers/psychology ; Child Development/physiology ; Adult ; Infant Care ; },
abstract = {Receiving social support from community and extended family has been typical for mothers with infants in human societies past and present. In non-industrialised contexts, infants of mothers with extended family support often have better health and higher survival through the vulnerable infant period, and hence shared infant care has a clear fitness benefit. However, there is scant evidence that these benefits continue in industrialised contexts. Better infant health and development with allocare support would indicate continued evolutionary selection for allocare. The research reported here used multiple logistic regression analysis to test whether a lack of family and other social support for mothers was associated with an increased risk of developmental delay in 9-month-old infants in the UK Millennium Cohort (analysis sample size, 15,696 infants). Extended family-based childcare during work hours and more maternal time spent with friends were the most influential kin and social support variables: infants of mothers with kin-based childcare versus all other childcare arrangements had a lower risk of developmental delay (OR = 0.61, 95% CIs: 0.46-0.82). Infants of mothers who spent no time with friends when compared with those who saw friends every day had double the odds of delay. Greater paternal involvement in infant care was associated with a lower odds of developmental delay. In conclusion, shared care of infants and social support for mothers may influence fitness-related traits in industrialised societies rather than being factors that influenced selection only in the past and in societies which retain close kin networks and a strong local community focus.},
}

Humans
Infant
*Developmental Disabilities
Female
*Social Support
Male
United Kingdom
Mothers/psychology
Child Development/physiology
Adult
Infant Care

@article {pmid38350872,
year = {2024},
author = {Araujo, NS and Ogihara, F and Martins, PM and Arias, MC},
title = {Insights from Melipona bicolor hybrid genome assembly: a stingless bee genome with chromosome-level scaffold.},
journal = {BMC genomics},
volume = {25},
number = {1},
pages = {171},
pmid = {38350872},
issn = {1471-2164},
support = {2019/23186-9; 2016/24669-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2019/23186-9; 2016/24669-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 40005980//Fonds De La Recherche Scientifique - FNRS/ ; 307356/2019-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; },
mesh = {Bees/genetics ; Animals ; *Ecosystem ; *Social Behavior ; Reproduction ; Chromosomes/genetics ; },
abstract = {BACKGROUND: The highly eusocial stingless bees are crucial pollinators of native and agricultural ecosystems. Nevertheless, genomic studies within this bee tribe remain scarce. We present the genome assembly of the stingless bee Melipona bicolor. This bee is a remarkable exception to the typical single-queen colony structure, since in this species, multiple queens may coexist and share reproductive duties, resulting in genetically diverse colonies with weak kinship connections. As the only known genuinely polygynous bee, M. bicolor's genome provides a valuable resource for investigating sociality beyond kin selection.

RESULTS: The genome was assembled employing a hybrid approach combining short and long reads, resulting in 241 contigs spanning 259 Mb (N50 of 6.2 Mb and 97.5% complete BUSCOs). Comparative analyses shed light on some evolutionary aspects of stingless bee genomics, including multiple chromosomal rearrangements in Melipona. Additionally, we explored the evolution of venom genes in M. bicolor and other stingless bees, revealing that, apart from two genes, the conserved repertoire of venom components remains under purifying selection in this clade.

CONCLUSION: This study advances our understanding of stingless bee genomics, contributing to the conservation efforts of these vital pollinators and offering insights into the evolutionary mechanisms driving their unique adaptations.},
}

Bees/genetics
Animals
*Ecosystem
*Social Behavior
Reproduction
Chromosomes/genetics

@article {pmid38309717,
year = {2024},
author = {Downing, PA},
title = {Michener's group-size paradox in cooperatively breeding birds.},
journal = {Journal of evolutionary biology},
volume = {37},
number = {3},
pages = {353-359},
doi = {10.1093/jeb/voae008},
pmid = {38309717},
issn = {1420-9101},
support = {//University of Oulu/ ; 336449//Academy of Finland/ ; },
mesh = {Humans ; Animals ; *Altruism ; *Birds ; Breeding ; Head ; Reproduction ; },
abstract = {According to Michener's paradox, most altruistic groups in nature should be small and large groups should not exist. This is because per capita productivity is thought to decrease as groups get larger, meaning that the share of indirect fitness available to each group member declines, which favours dispersal. The empirical evidence for a decrease in per capita productivity is contradictory, however, and limited to the social Hymenoptera. I report that per capita reproductive success decreased with increasing group size across 26 cooperatively breeding bird species. Small groups comprising two or three individuals were the most common (79% of 16,101 groups), and these had the highest per capita reproductive success. This close fit between per capita reproductive success and the distribution of group sizes in nature suggests that it may indeed be difficult for large groups to evolve through indirect fitness benefits alone.},
}

Humans
Animals
*Altruism
*Birds
Breeding
Head
Reproduction

@article {pmid38274864,
year = {2024},
author = {Schroeder, JL and Worm, AJ and Sweet, AD and Rolland, V},
title = {Genomic data reveal unexpected relatedness between a brown female Eastern Bluebird and her brood.},
journal = {Ecology and evolution},
volume = {14},
number = {1},
pages = {e10851},
pmid = {38274864},
issn = {2045-7758},
abstract = {Because plumage coloration is frequently involved in sexual selection, for both male and female mate choice, birds with aberrant plumage should have fewer mating opportunities and thus lower reproductive output. Here we report an Eastern Bluebird (Sialia sialis) female with a brown phenotype that raised a brood of four chicks to fledging. The brown female and her mate were only related to their social offspring to the second degree and one of the offspring was a half-sibling. We propose four family tree scenarios and discuss their implications (e.g., extra-pair paternity, conspecific brood parasitism). Regardless of the tree, the brown female was able to find a mate, which may have been facilitated by the bottleneck created by the severe snowstorms in February 2021.},
}

@article {pmid38267842,
year = {2024},
author = {Chapman, H and Hsiung, KC and Rawlinson, I and Galimov, ER and Gems, D},
title = {Colony level fitness analysis identifies a trade-off between population growth rate and dauer yield in Caenorhabditis elegans.},
journal = {BMC ecology and evolution},
volume = {24},
number = {1},
pages = {13},
pmid = {38267842},
issn = {2730-7182},
mesh = {Animals ; *Caenorhabditis elegans ; *Population Growth ; Apoptosis ; Benchmarking ; Biological Assay ; },
abstract = {BACKGROUND: In the evolution from unicellular to multicellular life forms, natural selection favored reduced cell proliferation and even programmed cell death if this increased organismal fitness. Could reduced individual fertility or even programmed organismal death similarly increase the fitness of colonies of closely-related metazoan organisms? This possibility is at least consistent with evolutionary theory, and has been supported by computer modelling. Caenorhabditis elegans has a boom and bust life history, where populations of nematodes that are sometimes near clonal subsist on and consume food patches, and then generate dauer larva dispersal propagules. A recent study of an in silico model of C. elegans predicted that one determinant of colony fitness (measured as dauer yield) is minimization of futile food consumption (i.e. that which does not contribute to dauer yield). One way to achieve this is to optimize colony population structure by adjustment of individual fertility.

RESULTS: Here we describe development of a C. elegans colony fitness assay, and its use to investigate the effect of altering population structure on colony fitness after population bust. Fitness metrics measured were speed of dauer production, and dauer yield, an indirect measure of efficiency of resource utilization (i.e. conversion of food into dauers). We find that with increasing founder number, speed of dauer production increases (due to earlier bust) but dauer yield rises and falls. In addition, some dauer recovery was detected soon after the post-colony bust peak of dauer yield, suggesting possible bet hedging among dauers.

CONCLUSIONS: These results suggest the presence of a fitness trade-off at colony level between speed and efficiency of resource utilization in C. elegans. They also provide indirect evidence that population structure is a determinant of colony level fitness, potentially by affecting level of futile food consumption.},
}

Animals
*Caenorhabditis elegans
*Population Growth
Apoptosis
Benchmarking
Biological Assay

@article {pmid38246487,
year = {2024},
author = {Scott, TW},
title = {Crozier's paradox and kin recognition: Insights from simplified models.},
journal = {Journal of theoretical biology},
volume = {581},
number = {},
pages = {111735},
doi = {10.1016/j.jtbi.2024.111735},
pmid = {38246487},
issn = {1095-8541},
mesh = {*Genetics, Population ; *Biological Evolution ; Altruism ; },
abstract = {Crozier's paradox suggests that genetic kin recognition will not be evolutionarily stable. The problem is that more common tags (markers) are more likely to be recognised and helped. This causes common tags to increase in frequency, eliminating the genetic variability that is required for genetic kin recognition. In recent years, theoretical models have resolved Crozier's paradox in different ways, but they are based on very complicated multi-locus population genetics. Consequently, it is hard to see exactly what is going on, and whether different theoretical resolutions of Crozier's paradox lead to different types of kin discrimination. I address this by making unrealistic simplifying assumptions to produce a more tractable and understandable model of Crozier's paradox. I use this to interpret a more complex multi-locus population genetic model where I have not made the same simplifying assumptions. I explain how Crozier's paradox can be resolved, and show that only one known theoretical resolution of Crozier's paradox - multiple social encounters - leads without restrictive assumptions to the type of highly cooperative and reliable form of kin discrimination that we observe in nature. More generally, I show how adopting a methodological approach where complex models are compared with simplified ones can lead to greater understanding and accessibility.},
}

*Genetics, Population
*Biological Evolution
Altruism

@article {pmid38232110,
year = {2024},
author = {Komatsu, H and Kubota, H and Asano, K and Nagai, Y},
title = {Effect of information provision by familial nudging on attitudes toward offshore wind power.},
journal = {PloS one},
volume = {19},
number = {1},
pages = {e0297199},
pmid = {38232110},
issn = {1932-6203},
mesh = {Humans ; *Wind ; *Attitude ; },
abstract = {Offshore wind power (OWP) is a promising way to achieve decarbonization and tackle global climate change, but acceptance by residents is an important issue for site location. Information provision could be a more cost-effective intervention than debates or subsidies, assuming that scientifically correct information alone is insufficient and information design to boost the message effects considering realistic human responses is necessary. Thus, we designed nudging messages to increase acceptance of OWP, using a message framework to moderate risk-averse attitudes by reminding readers of familial support based on insights from kin selection theory from evolutionary psychology. A randomized controlled trial based on an internet survey of more than 4000 responses from the general public was performed to investigate the message effects. The messages significantly moderated the risk-averse attitudes toward OWP by 0.228 on average on a five-point Likert scale, which meant that about 5 people out of 100 changed their attitudes to be safer by 1 point. This suggests that disseminating flyers using nudging messages might be an effective way to increase acceptance. We also extracted responses from those who mentioned fisheries in an open-ended question as an alternative to actual fishers. Responses from this segment were more complex and the message effects were limited compared with those who did not mention fisheries; although the attitudes toward OWP before receiving the messages were safer, reading descriptions for potential risks on fisheries may have unexpectedly led them to focus on the risks of which they were unaware at first. Because information provision based on nudging is effective but just one of a wide variety of political interventions available, practitioners should consider a combination of multiple options instead of using only nudging messages.},
}

Humans
*Wind
*Attitude

@article {pmid38214699,
year = {2024},
author = {Pretelli, I and Crittenden, AN and Dounias, E and Friant, S and Koster, J and Kramer, KL and Mangola, SM and Saez, AM and Lew-Levy, S},
title = {Child and adolescent foraging: New directions in evolutionary research.},
journal = {Evolutionary anthropology},
volume = {33},
number = {2},
pages = {e22020},
doi = {10.1002/evan.22020},
pmid = {38214699},
issn = {1520-6505},
support = {ANR-17-EURE-0010//French National Research Agency (ANR)/ ; },
mesh = {Adolescent ; Humans ; Child ; *Feeding Behavior ; },
abstract = {Young children and adolescents in subsistence societies forage for a wide range of resources. They often target child-specific foods, they can be very successful foragers, and they share their produce widely within and outside of their nuclear family. At the same time, while foraging, they face risky situations and are exposed to diseases that can influence their immune development. However, children's foraging has largely been explained in light of their future (adult) behavior. Here, we reinterpret findings from human behavioral ecology, evolutionary medicine and cultural evolution to center foraging children's contributions to life history evolution, community resilience and immune development. We highlight the need to foreground immediate alongside delayed benefits and costs of foraging, including inclusive fitness benefits, when discussing children's food production from an evolutionary perspective. We conclude by recommending that researchers carefully consider children's social and ecological context, develop cross-cultural perspectives, and incorporate children's foraging into Indigenous sovereignty discourse.},
}

Adolescent
Humans
Child
*Feeding Behavior

@article {pmid38214204,
year = {2024},
author = {Qian, C and Wen, C and Guo, X and Yang, X and Wen, X and Ma, T and Wang, C},
title = {Gregariousness in lepidopteran larvae.},
journal = {Insect science},
volume = {},
number = {},
pages = {},
doi = {10.1111/1744-7917.13312},
pmid = {38214204},
issn = {1744-7917},
support = {2022A1515010080//Guangdong Basic and Applied Basic Research Foundation/ ; },
abstract = {The gregarious lifestyle of lepidopteran larvae is diverse and shaped by a complex interplay of ecological and evolutionary factors. Our review showed that the larval-aggregation behavior has been reported in 23 lepidopteran families, indicating multiple evolution of this behavior. Some larvae live in sibling groups throughout all larval instars and even pupation stages, which may result from the kin-selection. In contrast, group fusion may occur among different sibling or foraging groups of larvae and form larger aggregates, and the gregariousness of these species might be driven by the group-selection. While group size and foraging patterns vary greatly across species, it is generally associated with improved larval survivorship and accelerated development. However, the advantages of group living, such as facilitating feeding activities, adjusting the temperature, and defending natural enemies, may diminish along with development, with strong intraspecific competition occurring at later instars, even when food is abundant. Therefore, the group sizes and fission-fusion dynamics of certain gregarious lepidopteran larvae may be a consequence of their cost-benefit balance depending on various biotic and abiotic factors. Trail and aggregation pheromones, silk trails, or body contact contribute to collective movement and group cohesion of gregarious lepidopteran larvae. However, frequent contact among group members may cause the horizontal transmission of pathogens and pesticides, which may bring an integrated pest management strategy controlling gregarious lepidopteran pests.},
}

@article {pmid38207145,
year = {2024},
author = {Schmid, M and Rueffler, C and Lehmann, L and Mullon, C},
title = {Resource Variation Within and Between Patches: Where Exploitation Competition, Local Adaptation, and Kin Selection Meet.},
journal = {The American naturalist},
volume = {203},
number = {1},
pages = {E19-E34},
doi = {10.1086/727483},
pmid = {38207145},
issn = {1537-5323},
mesh = {Humans ; Population Dynamics ; *Ecosystem ; *Models, Theoretical ; Genetic Drift ; Polymorphism, Genetic ; Biological Evolution ; Selection, Genetic ; },
abstract = {AbstractIn patch- or habitat-structured populations, different processes can favor adaptive polymorphism at different scales. While spatial heterogeneity can generate spatially disruptive selection favoring variation between patches, local competition can lead to locally disruptive selection promoting variation within patches. So far, almost all theory has studied these two processes in isolation. Here, we use mathematical modeling to investigate how resource variation within and between habitats influences the evolution of variation in a consumer population where individuals compete in finite patches connected by dispersal. We find that locally and spatially disruptive selection typically act in concert, favoring polymorphism under a wider range of conditions than when in isolation. But when patches are small and dispersal between them is low, kin competition inhibits the emergence of polymorphism, especially when the latter is driven by local competition for resources. We further use our model to clarify what comparisons between trait and neutral genetic differentiation (QST/FST comparisons) can tell about the nature of selection. Overall, our results help us understand the interaction between two major drivers of polymorphism: locally and spatially disruptive selection, and how this interaction is modulated by the unavoidable effects of kin selection under limited dispersal.},
}

Humans
Population Dynamics
*Ecosystem
*Models, Theoretical
Genetic Drift
Polymorphism, Genetic
Biological Evolution
Selection, Genetic

@article {pmid38161549,
year = {2023},
author = {Hayman, J and Fortune, DW},
title = {Sexual Orientation in Twins: Evidence That Human Sexual Identity May Be Determined Five Days Following Fertilization.},
journal = {Cureus},
volume = {15},
number = {12},
pages = {e51346},
pmid = {38161549},
issn = {2168-8184},
abstract = {Human same-sex sexual attraction has been recorded from the beginning of written history. It remains a controversial topic, but recent theories favor prenatal influences. A paradox is the occurrence of same-sex orientation in twins in that there is a higher level of concordance in monozygous twins compared to that in dizygous twins or non-twin siblings. If sexual orientation was entirely genetically determined monozygous twins would be expected to have identical sexual inclinations. Monozygous twins have twice the incidence of sexual concordance in comparison to dizygous twins but a third of these pairs have different sexual identities. An explanation for this disparity may lie in the time an embryo splits to form two separate fetuses. If splitting occurs early in twin development each twin may develop his or her own sexual identity; splitting occurring later results in twins that have the same sexual dispositions. A possible process for such determination may be in the mitochondria, with universal maternal inheritance of a proportion of normal functioning but alternate mitochondria. Variation in the distribution of these mitochondria in neural precursor cells becomes a mechanism for the development of intrinsic sexual orientation and for the spectrum of human sexual inclinations. The timing of embryonic splitting may be determined from the examination of fetal membranes, and the concept of early fetal sexual orientation is open to support or disproval.},
}

@article {pmid38117204,
year = {2023},
author = {Belcher, LJ and Dewar, AE and Hao, C and Katz, Z and Ghoul, M and West, SA},
title = {SOCfinder: a genomic tool for identifying social genes in bacteria.},
journal = {Microbial genomics},
volume = {9},
number = {12},
pages = {},
pmid = {38117204},
issn = {2057-5858},
mesh = {*Genomics ; *Bacteria/genetics ; Genes, Bacterial/genetics ; Computational Biology ; Anti-Bacterial Agents ; Pseudomonas aeruginosa ; },
abstract = {Bacteria cooperate by working collaboratively to defend their colonies, share nutrients, and resist antibiotics. Nevertheless, our understanding of these remarkable behaviours primarily comes from studying a few well-characterized species. Consequently, there is a significant gap in our understanding of microbial social traits, particularly in natural environments. To address this gap, we can use bioinformatic tools to identify genes that control cooperative or otherwise social traits. Existing tools address this challenge through two approaches. One approach is to identify genes that encode extracellular proteins, which can provide benefits to neighbouring cells. An alternative approach is to predict gene function using annotation tools. However, these tools have several limitations. Not all extracellular proteins are cooperative, and not all cooperative behaviours are controlled by extracellular proteins. Furthermore, existing functional annotation methods frequently miss known cooperative genes. We introduce SOCfinder as a new tool to find bacterial genes that control cooperative or otherwise social traits. SOCfinder combines information from several methods, considering if a gene is likely to [1] code for an extracellular protein [2], have a cooperative functional annotation, or [3] be part of the biosynthesis of a cooperative secondary metabolite. We use data on two extensively-studied species (P. aeruginosa and B. subtilis) to show that SOCfinder is better at finding known cooperative genes than existing tools. We also use theory from population genetics to identify a signature of kin selection in SOCfinder cooperative genes, which is lacking in genes identified by existing tools. SOCfinder opens up a number of exciting directions for future research, and is available to download from https://github.com/lauriebelch/SOCfinder.},
}

*Genomics
*Bacteria/genetics
Genes, Bacterial/genetics
Computational Biology
Anti-Bacterial Agents
Pseudomonas aeruginosa

@article {pmid38018113,
year = {2023},
author = {Rodrigues, AMM and Gardner, A},
title = {Transmission of social status drives cooperation and offspring philopatry.},
journal = {Proceedings. Biological sciences},
volume = {290},
number = {2011},
pages = {20231314},
pmid = {38018113},
issn = {1471-2954},
mesh = {Animals ; Humans ; *Biological Evolution ; *Social Status ; Models, Theoretical ; Fertility ; },
abstract = {The evolution of cooperation depends on two crucial overarching factors: relatedness, which describes the extent to which the recipient shares genes in common with the actor; and quality, which describes the recipient's basic capacity to transmit genes into the future. While most research has focused on relatedness, there is a growing interest in understanding how quality modulates the evolution of cooperation. However, the impact of inheritance of quality on the evolution of cooperation remains largely unexplored, especially in spatially structured populations. Here, we develop a mathematical model to understand how inheritance of quality, in the form of social status, influences the evolution of helping and harming within social groups in a viscous-population setting. We find that: (1) status-reversal transmission, whereby parental and offspring status are negatively correlated, strongly inhibits the evolution of cooperation, with low-status individuals investing less in cooperation and high-status individuals being more prone to harm; (2) transmission of high status promotes offspring philopatry, with more cooperation being directed towards the higher-dispersal social class; and (3) fertility inequality and inter-generational status inheritance reduce within-group conflict. Overall, our study highlights the importance of considering different mechanisms of phenotypic inheritance, including social support, and their potential interactions in shaping animal societies.},
}

Animals
Humans
*Biological Evolution
*Social Status
Models, Theoretical
Fertility

@article {pmid38016596,
year = {2024},
author = {Reynolds-Hogland, M and Brooks, C and Ramsey, AB and Hogland, JS and Pilgrim, KL and Engkjer, C and Ramsey, PW},
title = {Long-term video and genetic data yield insights into complex sociality of a solitary large carnivore.},
journal = {Behavioural processes},
volume = {214},
number = {},
pages = {104972},
doi = {10.1016/j.beproc.2023.104972},
pmid = {38016596},
issn = {1872-8308},
mesh = {Animals ; Female ; Male ; *Ursidae ; Animals, Wild ; Social Behavior ; Reproduction ; Ethology ; },
abstract = {American black bears (Ursus americanus) may be more social than currently understood. We used long-term video and genetic data to evaluate social interactions among wild, independent-aged black bear on a conservation property in western Montana, USA. We used multinomial logistic regression to evaluate predictions about male-male interactions within the context of individual fitness, female-female interactions within the context of inclusive fitness, and male-female interactions within the context of female counterstrategies to infanticide. Overall, our findings challenged the assumption that independent-aged bears interact only during the mating season or when concentrated feeding sites are present. We documented 169 interaction events by at least 66 bear pairs, 92 (54%) of which occurred outside of the peak mating season and in the absence of concentrated feeding sites. The probability that male-male pairs engaged in play and other non-agonistic behaviours was higher than that for female-female pairs. Conversely, the probability that female-female pairs engaged in chase behaviour was higher than that for male-male and male-female pairs. We documented evidence of female mate choice, female resource defense, sexually selected infanticide (SSI), and female counterstrategies to avoid SSI. Our findings improve our understanding of ursid ethology and underscore the complexity of ursid sociality.},
}

Animals
Female
Male
*Ursidae
Animals, Wild
Social Behavior
Reproduction
Ethology

@article {pmid37975504,
year = {2023},
author = {Alizon, S},
title = {Multiple infection theory rather than 'socio-virology'? A commentary on Leeks et al. 2023.},
journal = {Journal of evolutionary biology},
volume = {36},
number = {11},
pages = {1571-1576},
doi = {10.1111/jeb.14245},
pmid = {37975504},
issn = {1420-9101},
mesh = {*Onions ; *Cooperative Behavior ; Genetic Fitness ; Biological Evolution ; },
}

*Onions
*Cooperative Behavior
Genetic Fitness
Biological Evolution

@article {pmid37969551,
year = {2023},
author = {McCormack, JL and Arbuckle, K and Fullard, K and Amos, W and Nichols, HJ},
title = {Lack of intergenerational reproductive conflict, rather than lack of inclusive fitness benefits, explains absence of post-reproductive lifespan in long-finned pilot whales.},
journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology},
volume = {34},
number = {6},
pages = {950-959},
pmid = {37969551},
issn = {1045-2249},
abstract = {Life-history theory suggests that individuals should reproduce until death, yet females of a small number of mammals live for a significant period after ceasing reproduction, a phenomenon known as post-reproductive lifespan. It is thought that the evolution of this trait is facilitated by increasing local relatedness throughout a female's lifetime. This allows older females to gain inclusive fitness through helping their offspring (known as a mother effect) and/or grandoffspring (known as a grandmother effect), rather than gaining direct fitness through reproducing. However, older females may only benefit from stopping reproducing when their direct offspring compete with those of their daughters. Here, we investigate whether a lack of post-reproductive lifespan in long-finned pilot whales (Globicephala melas) results from minimal benefits incurred from the presence of older females, or from a lack of costs resulting from mother-daughter co-reproduction. Using microsatellite data, we conducted parentage analysis on individuals from 25 pods and find that younger females were more likely to have offspring if their mother was present in their pod, indicating that mothers may assist inexperienced daughters to reproduce. However, we found no evidence of reproductive conflict between co-reproducing mothers and daughters, indicating that females may be able to reproduce into old age while simultaneously aiding their daughters in reproduction. This highlights the importance of reproductive conflict in the evolution of a post-reproductive lifespan and demonstrates that mother and grandmother effects alone do not result in the evolution of a post-reproductive lifespan.},
}

@article {pmid37934441,
year = {2023},
author = {Liechty, T and Woo, M and Rice, LA and Chiu, CY and Kirkpatrick, S and Hankins, K and Hedgspeth, E and Nichols, A and Porter, C and Smeltzer, M and Adamson, B},
title = {Community Partners' Perspectives on Partnering With an Academic Research Team to Promote Disability-inclusive Fitness Programming.},
journal = {Progress in community health partnerships : research, education, and action},
volume = {17},
number = {3},
pages = {429-437},
pmid = {37934441},
issn = {1557-055X},
mesh = {Humans ; *Community-Based Participatory Research ; *Disabled Persons ; Schools ; Communication ; Exercise ; },
abstract = {BACKGROUND: Community-based fitness programs can support public health by providing access to physical activity opportunities for a vulnerable population with significant barriers. Unfortunately, programs specifically designed for people with disabilities (PWD) and staff training to promote inclusion for PWD in general population programs is limited. The current study aimed to review an on-going partnership that had formed to address this need.

OBJECTIVES: The purpose of this study was to assess community partners' experiences with a community-academic partnership designed to implement a fitness program for people with multiple sclerosis and also to promote inclusion for PWD in community-based fitness programming.

METHODS: Semi-structured interviews were conducted with six community partners who had been engaged in a formal partnership with the academic institution for 2 or more years to understand partners' experiences and perspectives about the partnership. Interviews were audio/video recorded, transcribed verbatim, and analyzed thematically.

RESULTS: Participants described their experiences as falling into four main areas. Pre-partnership experiences (or lack thereof) shaped participants views on entering into academic partnerships. Communication and planning for mutual benefit were key to getting the partnership started. Partners identified challenges and factors for success while they were in the thick of partnership activities. Finally, evaluation allowed for assessment and improvement of the partnership itself and its ultimate goals.

CONCLUSIONS: Findings suggest that academic-community partnerships can be ideal for promoting inclusion for PWD and highlight insights that can be used in the development of future partnerships.},
}

Humans
*Community-Based Participatory Research
*Disabled Persons
Schools
Communication
Exercise

@article {pmid37926425,
year = {2024},
author = {Gardner, A},
title = {A geometric approach to the evolution of altruism.},
journal = {Journal of theoretical biology},
volume = {576},
number = {},
pages = {111653},
doi = {10.1016/j.jtbi.2023.111653},
pmid = {37926425},
issn = {1095-8541},
mesh = {*Altruism ; *Selection, Genetic ; Biological Evolution ; Mathematics ; Probability ; },
abstract = {Fisher's geometric model provides a powerful tool for making predictions about key properties of Darwinian adaptation. Here, I apply the geometric model to predict differences between the evolution of altruistic versus nonsocial phenotypes. I recover Kimura's prediction that probability of fixation is greater for mutations of intermediate size, but I find that the effect size that maximises probability of fixation is relatively small in the context of altruism and relatively large in the context of nonsocial phenotypes, and that the overall probability of fixation is lower for altruism and is higher for nonsocial phenotypes. Accordingly, the first selective substitution is expected to be smaller, and to take longer, in the context of the evolution of altruism. These results strengthen the justification for employing streamlined social evolutionary methodologies that assume adaptations are underpinned by many genes of small effect.},
}

*Altruism
*Selection, Genetic
Biological Evolution
Mathematics
Probability

@article {pmid37867189,
year = {2023},
author = {Szilágyi, A and Czárán, T and Santos, M and Szathmáry, E},
title = {Directional selection coupled with kin selection favors the establishment of senescence.},
journal = {BMC biology},
volume = {21},
number = {1},
pages = {230},
pmid = {37867189},
issn = {1741-7007},
mesh = {Humans ; *Aging/genetics ; *Longevity ; Mutation ; Reproduction ; Biological Evolution ; Selection, Genetic ; },
abstract = {BACKGROUND: Conventional wisdom in evolutionary theory considers aging as a non-selected byproduct of natural selection. Based on this, conviction aging was regarded as an inevitable phenomenon. It was also thought that in the wild organisms tend to die from diseases, predation and other accidents before they could reach the time when senescence takes its course. Evidence has accumulated, however, that aging is not inevitable and there are organisms that show negative aging even. Furthermore, old age does play a role in the deaths of many different organisms in the wild also. The hypothesis of programmed aging posits that a limited lifespan can evolve as an adaptation (i.e., positively selected for) in its own right, partly because it can enhance evolvability by eliminating "outdated" genotypes. A major shortcoming of this idea is that non-aging sexual individuals that fail to pay the demographic cost of aging would be able to steal good genes by recombination from aging ones.

RESULTS: Here, we show by a spatially explicit, individual-based simulation model that aging can positively be selected for if a sufficient degree of kin selection complements directional selection. Under such conditions, senescence enhances evolvability because the rate of aging and the rate of recombination play complementary roles. The selected aging rate is highest at zero recombination (clonal reproduction). In our model, increasing extrinsic mortality favors evolved aging by making up free space, thereby decreasing competition and increasing drift, even when selection is stabilizing and the level of aging is set by mutation-selection balance. Importantly, higher extrinsic mortality is not a substitute for evolved aging under directional selection either. Reduction of relatedness decreases the evolved level of aging; chance relatedness favors non-aging genotypes. The applicability of our results depends on empirical values of directional and kin selection in the wild.

CONCLUSIONS: We found that aging can positively be selected for in a spatially explicit population model when sufficiently strong directional and kin selection prevail, even if reproduction is sexual. The view that there is a conceptual link between giving up clonal reproduction and evolving an aging genotype is supported by computational results.},
}

Humans
*Aging/genetics
*Longevity
Mutation
Reproduction
Biological Evolution
Selection, Genetic

@article {pmid37829498,
year = {2023},
author = {Belcher, LJ and Dewar, AE and Hao, C and Ghoul, M and West, SA},
title = {Signatures of kin selection in a natural population of the bacteria Bacillus subtilis.},
journal = {Evolution letters},
volume = {7},
number = {5},
pages = {315-330},
pmid = {37829498},
issn = {2056-3744},
support = {834164/ERC_/European Research Council/International ; },
abstract = {Laboratory experiments have suggested that bacteria perform a range of cooperative behaviors, which are favored because they are directed toward relatives (kin selection). However, there is a lack of evidence for cooperation and kin selection in natural bacterial populations. Molecular population genetics offers a promising method to study natural populations because the theory predicts that kin selection will lead to relaxed selection, which will result in increased polymorphism and divergence at cooperative genes. Examining a natural population of Bacillus subtilis, we found consistent evidence that putatively cooperative traits have higher polymorphism and greater divergence than putatively private traits expressed at the same rate. In addition, we were able to eliminate alternative explanations for these patterns and found more deleterious mutations in genes controlling putatively cooperative traits. Overall, our results suggest that cooperation is favored by kin selection, with an average relatedness of r = .79 between interacting individuals.},
}

@article {pmid37817595,
year = {2023},
author = {Bourke, AFG},
title = {Conflict and conflict resolution in the major transitions.},
journal = {Proceedings. Biological sciences},
volume = {290},
number = {2008},
pages = {20231420},
pmid = {37817595},
issn = {1471-2954},
mesh = {Humans ; *Negotiating ; *Biological Evolution ; Sexual Behavior ; },
abstract = {Conflict and conflict resolution have been argued to be fundamental to the major transitions in evolution. These were key events in life's history in which previously independently living individuals cooperatively formed a higher-level individual, such as a multicellular organism or eusocial colony. Conflict has its central role because, to proceed stably, the evolution of individuality in each major transition required within-individual conflict to be held in check. This review revisits the role of conflict and conflict resolution in the major transitions, addressing recent work arguing for a minor role. Inclusive fitness logic suggests that differences between the kin structures of clones and sexual families support the absence of conflict at the origin of multicellularity but, by contrast, suggest that key conflicts existed at the origin of eusociality. A principal example is conflict over replacing the founding queen (queen replacement). Following the origin of each transition, conflict remained important, because within-individual conflict potentially disrupts the attainment of maximal individuality (organismality) in the system. The conclusion is that conflict remains central to understanding the major transitions, essentially because conflict arises from differences in inclusive fitness optima while conflict resolution can help the system attain a high degree of coincidence of inclusive fitness interests.},
}

Humans
*Negotiating
*Biological Evolution
Sexual Behavior

@article {pmid37788701,
year = {2023},
author = {Scott, TW and Wild, G},
title = {How to make an inclusive-fitness model.},
journal = {Proceedings. Biological sciences},
volume = {290},
number = {2008},
pages = {20231310},
pmid = {37788701},
issn = {1471-2954},
mesh = {Humans ; *Biological Evolution ; *Social Behavior ; Altruism ; Reproduction ; Sex Ratio ; Selection, Genetic ; Genetic Fitness ; },
abstract = {Social behaviours are typically modelled using neighbour-modulated fitness, which focuses on individuals having their fitness altered by neighbours. However, these models are either interpreted using inclusive fitness, which focuses on individuals altering the fitness of neighbours, or not interpreted at all. This disconnect leads to interpretational mistakes and obscures the adaptive significance of behaviour. We bridge this gap by presenting a systematic methodology for constructing inclusive-fitness models. We find a behaviour's 'inclusive-fitness effect' by summing primary and secondary deviations in reproductive value. Primary deviations are the immediate result of a social interaction; for example, the cost and benefit of an altruistic act. Secondary deviations are compensatory effects that arise because the total reproductive value of the population is fixed; for example, the increased competition that follows an altruistic act. Compared to neighbour-modulated fitness methodologies, our approach is often simpler and reveals the model's inclusive-fitness narrative clearly. We implement our methodology first in a homogeneous population, with supplementary examples of help under synergy, help in a viscous population and Creel's paradox. We then implement our methodology in a class-structured population, where the advantages of our approach are most evident, with supplementary examples of altruism between age classes, and sex-ratio evolution.},
}

Humans
*Biological Evolution
*Social Behavior
Altruism
Reproduction
Sex Ratio
Selection, Genetic
Genetic Fitness

@article {pmid37766488,
year = {2023},
author = {Li, Z and Chen, S and Wei, S and Komdeur, J and Lu, X},
title = {Should sons breed independently or help? Local relatedness matters.},
journal = {The Journal of animal ecology},
volume = {92},
number = {11},
pages = {2189-2200},
doi = {10.1111/1365-2656.14005},
pmid = {37766488},
issn = {1365-2656},
mesh = {Humans ; Male ; Animals ; *Nuclear Family ; Social Behavior ; *Passeriformes/genetics ; Breeding ; Reproduction ; Cooperative Behavior ; },
abstract = {In cooperatively breeding birds, why do some individuals breed independently but others have to help at home? This question has been rarely addressed despite its fundamental importance for understanding the evolution of social cooperation. We address it using 15 years of data from Tibetan ground tits Pseudopodoces humilis where helpers consist of younger males. Since whether younger males successfully breed depends critically on their chances to occupy territories nearby home, our analytic strategy is to identify the determinants of individual differences in gaining territory ownership among these ready-to-breed males. Across widowed, last-year helper and yearling males, an age advantage was evident in inheriting resident territories, occupying adjacent vacancies and budding off part of adjacent territories, which left some last-year helpers and most yearling males to take the latter two routes. These males were more likely to acquire a territory if they were genetically related to the previous or current territory owners; otherwise they remained on natal territories as helpers. The relatedness effect can arise from the prior residence advantage established in the preceding winter when younger males followed their parents to perform kin-directed off-territory forays. Our research highlights the key role of local kinship in determining younger males' territory acquisition and thus their fate in terms of independent reproduction versus help. This finding provides insight into the formation of kin-based, facultative cooperative societies prevailing among vertebrates.},
}

Humans
Male
Animals
*Nuclear Family
Social Behavior
*Passeriformes/genetics
Breeding
Reproduction
Cooperative Behavior

@article {pmid37746895,
year = {2023},
author = {Bresnahan, ST and Galbraith, D and Ma, R and Anton, K and Rangel, J and Grozinger, CM},
title = {Beyond conflict: Kinship theory of intragenomic conflict predicts individual variation in altruistic behaviour.},
journal = {Molecular ecology},
volume = {32},
number = {21},
pages = {5823-5837},
doi = {10.1111/mec.17145},
pmid = {37746895},
issn = {1365-294X},
support = {DGE1255832//Division of Graduate Education/ ; MCB-0950896//Division of Molecular and Cellular Biosciences/ ; PEN04716//National Institute of Food and Agriculture/ ; },
abstract = {Behavioural variation is essential for animals to adapt to different social and environmental conditions. The Kinship Theory of Intragenomic Conflict (KTIC) predicts that parent-specific alleles can support different behavioural strategies to maximize allele fitness. Previous studies, including in honey bees (Apis mellifera), supported predictions of the KTIC for parent-specific alleles to promote selfish behaviour. Here, we test the KTIC prediction that for altruism-promoting genes (i.e. those that promote behaviours that support the reproductive fitness of kin), the allele with the higher altruism optimum should be selected to be expressed while the other is silenced. In honey bee colonies, workers act altruistically when tending to the queen by performing a 'retinue' behaviour, distributing the queen's mandibular pheromone (QMP) throughout the hive. Workers exposed to QMP do not activate their ovaries, ensuring they care for the queen's brood instead of competing to lay unfertilized eggs. Due to the haplodiploid genetics of honey bees, the KTIC predicts that response to QMP is favoured by the maternal genome. We report evidence for parent-of-origin effects on the retinue response behaviour, ovarian development and gene expression in brains of worker honey bees exposed to QMP, consistent with the KTIC. Additionally, we show enrichment for genes with parent-of-origin expression bias within gene regulatory networks associated with variation in bees' response to QMP. Our study demonstrates that intragenomic conflict can shape diverse social behaviours and influence expression patterns of single genes as well as gene networks.},
}

@article {pmid37700652,
year = {2023},
author = {Twyman, KZ and Gardner, A},
title = {Kin selection of time travel: the social evolutionary causes and consequences of dormancy.},
journal = {Proceedings. Biological sciences},
volume = {290},
number = {2006},
pages = {20231247},
pmid = {37700652},
issn = {1471-2954},
mesh = {Humans ; *Social Evolution ; *Altruism ; Travel ; },
abstract = {A basic mechanism of kin selection is limited dispersal, whereby individuals remain close to their place of origin such that even indiscriminate social interaction tends to modify the fitness of genealogical kin. Accordingly, the causes and consequences of dispersal have received an enormous amount of attention in the social evolution literature. This work has focused on dispersal of individuals in space, yet similar logic should apply to dispersal of individuals in time (e.g. dormancy). We investigate how kin selection drives the evolution of dormancy and how dormancy modulates the evolution of altruism. We recover dormancy analogues of key results that have previously been given for dispersal, showing that: (1) kin selection favours dormancy as a means of relaxing competition between relatives; (2) when individuals may adjust their dormancy behaviour to local density, they are favoured to do so, resulting in greater dormancy in high-density neighbourhoods and a concomitant 'constant non-dormant principle'; (3) when dormancy is constrained to be independent of density, there is no relationship between the rate of dormancy and the evolutionary potential for altruism; and (4) when dormancy is able to evolve in a density-dependent manner, a greater potential for altruism is expected in populations with lower dormancy.},
}

Humans
*Social Evolution
*Altruism
Travel

@article {pmid37670147,
year = {2023},
author = {Roper, M and Green, JP and Salguero-Gómez, R and Bonsall, MB},
title = {Inclusive fitness forces of selection in an age-structured population.},
journal = {Communications biology},
volume = {6},
number = {1},
pages = {909},
pmid = {37670147},
issn = {2399-3642},
support = {BB/M011224/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; },
mesh = {Humans ; *Exercise ; Population Dynamics ; *Population Growth ; Reproduction ; },
abstract = {Hamilton's force of selection acting against age-specific mortality is constant and maximal prior to the age of first reproduction, before declining to zero at the age of last reproduction. The force of selection acting on age-specific reproduction declines monotonically from birth in a growing or stationary population. Central to these results is the assumption that individuals do not interact with one another. This assumption is violated in social organisms, where an individual's survival and/or reproduction may shape the inclusive fitness of other group members. Yet, it remains unclear how the forces of selection might be modified when inclusive fitness, rather than population growth rate, is considered the appropriate metric for fitness. Here, we derive such inclusive fitness forces of selection, and show that selection on age-specific survival is not always constant before maturity, and can remain above zero in post-reproductive age classes. We also show how the force of selection on age-specific reproduction does not always decline monotonically from birth, but instead depends on the balance of costs and benefits of increasing reproduction to both direct and indirect fitness. Our theoretical framework provides an opportunity to expand our understanding of senescence across social species.},
}

Humans
*Exercise
Population Dynamics
*Population Growth
Reproduction

@article {pmid37667646,
year = {2023},
author = {Nonacs, P},
title = {Why do Hymenopteran workers drift to non-natal groups? Generalized reciprocity and the maximization of group and parental success.},
journal = {Journal of evolutionary biology},
volume = {36},
number = {10},
pages = {1365-1374},
doi = {10.1111/jeb.14215},
pmid = {37667646},
issn = {1420-9101},
mesh = {Humans ; Animals ; *Hymenoptera/genetics ; Biological Evolution ; Hybrid Vigor ; Social Behavior ; },
abstract = {Eusocial Hymenoptera are often characterized by having facultatively or obligately sterile worker castes. However, findings across an increasing number of species are that some workers are non-natal-they have 'drifted' away from where they were born and raised. Moreover, drifters are often indistinguishable from natal workers in the work and benefits provided to joined groups. This seems an evolutionary paradox of providing benefits to potentially unrelated individuals over close kin. Rather than being mistakes, drifting is proposed to be adaptive if joiners either gain inclusive fitness by preferentially moving to other kin groups or through generalized reciprocity in which exchanging workers across groups raises group-level genetic diversity and creates social heterosis. It is unclear, however, if reciprocity is unlikely because of a susceptibility to cheating. In resolving this question, a series of evolutionary simulations show: (1) Reciprocity can persist under a range of genetic assumptions and scenarios of cheating, (2) cheating almost always evolves, but can be expressed in a variety of ways that are not always predictable, (3) the inclusive fitness hypothesis is equally or more susceptible to cheating. Moreover, existing data in Hymenoptera (although not extensive) are more consistent with generalized reciprocity. This supports a hypothesis that drifting, as a phenomenon, may more often reflect maximization of group and parental fitness rather than fitness gains for the individual drifters.},
}

Humans
Animals
*Hymenoptera/genetics
Biological Evolution
Hybrid Vigor
Social Behavior

@article {pmid37642131,
year = {2023},
author = {Walasek, L and Brown, GDA},
title = {Incomparability and Incommensurability in Choice: No Common Currency of Value?.},
journal = {Perspectives on psychological science : a journal of the Association for Psychological Science},
volume = {},
number = {},
pages = {17456916231192828},
doi = {10.1177/17456916231192828},
pmid = {37642131},
issn = {1745-6924},
abstract = {Models of decision-making typically assume the existence of some common currency of value, such as utility, happiness, or inclusive fitness. This common currency is taken to allow comparison of options and to underpin everyday choice. Here we suggest instead that there is no universal value scale, that incommensurable values pervade everyday choice, and hence that most existing models of decision-making in both economics and psychology are fundamentally limited. We propose that choice objects can be compared only with reference to specific but nonuniversal "covering values." These covering values may reflect decision-makers' goals, motivations, or current states. A complete model of choice must accommodate the range of possible covering values. We show that abandoning the common-currency assumption in models of judgment and decision-making necessitates rank-based and "simple heuristics" models that contrast radically with conventional utility-based approaches. We note that if there is no universal value scale, then Arrow's impossibility theorem places severe bounds on the rationality of individual decision-making and hence that there is a deep link between the incommensurability of value, inconsistencies in human decision-making, and rank-based coding of value. More generally, incommensurability raises the question of whether it will ever be possible to develop single-quantity-maximizing models of decision-making.},
}

@article {pmid37637319,
year = {2023},
author = {Zhang, K and Zhang, ZQ},
title = {A thelytokous predatory mite is more cannibalistic towards distant kin.},
journal = {Current zoology},
volume = {69},
number = {5},
pages = {578-584},
pmid = {37637319},
issn = {1674-5507},
abstract = {Kin recognition has been widely observed in various taxa. Cannibalism avoidance may be a strong driver for the evolution of kin recognition, as it may avoid a reduction in inclusive fitness. Kin recognition has recently been observed in a generalist phytoseiid, Amblyseius herbicolus (Acari: Phytoseiidae). This study experimentally examined the degree of relatedness needed between prey larvae and cannibal adults of A. herbicolus for the occurrence of kin discrimination. The adults were individually placed in enclosed arenas with two prey, a daughter and a more distant related larva, to observe their cannibalizing choice. The adults of A. herbicolus did not discriminate between close relatives (daughter versus niece) but preferably cannibalized more distant kin (i.e., first and second cousins once removed). Phenotype matching and familiarization seem prominent as recognition mechanisms used by A. herbicolus adults. The effect of learning on kin recognition through prior contact in A. herbicolus requires further investigation. Studies on other adaptive functions of kin recognition of A. herbicolus, such as cooperation and parental care, may provide meaningful insights.},
}

@article {pmid37608718,
year = {2023},
author = {Úbeda, F and Wild, G},
title = {Microchimerism as a source of information on future pregnancies.},
journal = {Proceedings. Biological sciences},
volume = {290},
number = {2005},
pages = {20231142},
pmid = {37608718},
issn = {1471-2954},
mesh = {Pregnancy ; Humans ; Female ; *Chimerism ; *Information Sources ; Mothers ; Pelvis ; Placenta ; },
abstract = {Small numbers of fetal cells cross the placenta during pregnancy turning mothers into microchimeras. Fetal cells from all previous pregnancies accumulate forming the mother's fetal microchiome. What is significant about microchimeric cells is that they have been linked to health problems including reproductive and autoimmune diseases. Three decades after the discovery of fetal microchimerism, the function of these cells remains a mystery. Here, we contend that the role of microchimeric cells is to inform the fetus about the likelihood that its genes are present in future pregnancies. We argue that, when genes are more likely than average to be in future maternal siblings, fetuses will send a fixed number of cells that will not elicit a maternal immune response against them. However, when genes are less likely to be in future maternal siblings, fetuses will send an ever-increasing number of cells that will elicit an ever-stronger maternal immune response. Our work can explain the observed clinical association between microchimeric cells and pre-eclampsia. However, our work predicts that this association should be stronger in women with a genetically diverse microchiome. If supported by medical tests, our work would allow establishing the likelihood of pregnancy or autoimmune problems advising medical interventions.},
}

Pregnancy
Humans
Female
*Chimerism
*Information Sources
Mothers
Pelvis
Placenta

@article {pmid37588900,
year = {2022},
author = {He, QQ and Rui, JW and Zhang, L and Tao, Y and Wu, JJ and Mace, R and Ji, T},
title = {Communal breeding by women is associated with lower investment from husbands.},
journal = {Evolutionary human sciences},
volume = {4},
number = {},
pages = {e50},
pmid = {37588900},
issn = {2513-843X},
abstract = {According to Hamilton's rule, matrilineal-biased investment restrains men in matrilineal societies from maximising their inclusive fitness (the 'matrilineal puzzle'). A recent hypothesis argues that when women breed communally and share household resources, a man should help his sisters' household, rather than his wife's household, as investment to the later but not the former would be diluted by other unrelated members (Wu et al., 2013). According to this hypothesis, a man is less likely to help on his wife's farm when there are more women reproducing in the wife's household, because on average he would be less related to his wife's household. We used a farm-work observational dataset, that we collected in the matrilineal Mosuo in southwest China, to test this hypothesis. As predicted, high levels of communal breeding by women in his wife's households do predict less effort spent by men on their wife's farm, and communal breeding in men's natal households do not affect whether men help on their natal farms. Thus, communal breeding by women dilutes the inclusive fitness benefits men receive from investment to their wife and children, and may drive the evolution of matrilineal-biased investment by men. These results can help solve the 'matrilineal puzzle'.},
}

@article {pmid37528574,
year = {2023},
author = {Couto, A and Marty, S and Dawson, EH and d'Ettorre, P and Sandoz, JC and Montgomery, SH},
title = {Evolution of the neuronal substrate for kin recognition in social Hymenoptera.},
journal = {Biological reviews of the Cambridge Philosophical Society},
volume = {98},
number = {6},
pages = {2226-2242},
doi = {10.1111/brv.13003},
pmid = {37528574},
issn = {1469-185X},
mesh = {Bees ; Animals ; *Wasps/physiology ; Social Behavior ; *Ants ; Reproduction/physiology ; Selection, Genetic ; Biological Evolution ; Mammals ; },
abstract = {In evolutionary terms, life is about reproduction. Yet, in some species, individuals forgo their own reproduction to support the reproductive efforts of others. Social insect colonies for example, can contain up to a million workers that actively cooperate in tasks such as foraging, brood care and nest defence, but do not produce offspring. In such societies the division of labour is pronounced, and reproduction is restricted to just one or a few individuals, most notably the queen(s). This extreme eusocial organisation exists in only a few mammals, crustaceans and insects, but strikingly, it evolved independently up to nine times in the order Hymenoptera (including ants, bees and wasps). Transitions from a solitary lifestyle to an organised society can occur through natural selection when helpers obtain a fitness benefit from cooperating with kin, owing to the indirect transmission of genes through siblings. However, this process, called kin selection, is vulnerable to parasitism and opportunistic behaviours from unrelated individuals. An ability to distinguish kin from non-kin, and to respond accordingly, could therefore critically facilitate the evolution of eusociality and the maintenance of non-reproductive workers. The question of how the hymenopteran brain has adapted to support this function is therefore a fundamental issue in evolutionary neuroethology. Early neuroanatomical investigations proposed that social Hymenoptera have expanded integrative brain areas due to selection for increased cognitive capabilities in the context of processing social information. Later studies challenged this assumption and instead pointed to an intimate link between higher social organisation and the existence of developed sensory structures involved in recognition and communication. In particular, chemical signalling of social identity, known to be mediated through cuticular hydrocarbons (CHCs), may have evolved hand in hand with a specialised chemosensory system in Hymenoptera. Here, we compile the current knowledge on this recognition system, from emitted identity signals, to the molecular and neuronal basis of chemical detection, with particular emphasis on its evolutionary history. Finally, we ask whether the evolution of social behaviour in Hymenoptera could have driven the expansion of their complex olfactory system, or whether the early origin and conservation of an olfactory subsystem dedicated to social recognition could explain the abundance of eusocial species in this insect order. Answering this question will require further comparative studies to provide a comprehensive view on lineage-specific adaptations in the olfactory pathway of Hymenoptera.},
}

Bees
Animals
*Wasps/physiology
Social Behavior
*Ants
Reproduction/physiology
Selection, Genetic
Biological Evolution
Mammals

@article {pmid37492150,
year = {2023},
author = {Capp, JP and Thomas, F and Marusyk, A and M Dujon, A and Tissot, S and Gatenby, R and Roche, B and Ujvari, B and DeGregori, J and Brown, JS and Nedelcu, AM},
title = {The paradox of cooperation among selfish cancer cells.},
journal = {Evolutionary applications},
volume = {16},
number = {7},
pages = {1239-1256},
pmid = {37492150},
issn = {1752-4571},
support = {U01 CA271830/CA/NCI NIH HHS/United States ; },
abstract = {It is traditionally assumed that during cancer development, tumor cells abort their initially cooperative behavior (i.e., cheat) in favor of evolutionary strategies designed solely to enhance their own fitness (i.e., a "selfish" life style) at the expense of that of the multicellular organism. However, the growth and progress of solid tumors can also involve cooperation among these presumed selfish cells (which, by definition, should be noncooperative) and with stromal cells. The ultimate and proximate reasons behind this paradox are not fully understood. Here, in the light of current theories on the evolution of cooperation, we discuss the possible evolutionary mechanisms that could explain the apparent cooperative behaviors among selfish malignant cells. In addition to the most classical explanations for cooperation in cancer and in general (by-product mutualism, kin selection, direct reciprocity, indirect reciprocity, network reciprocity, group selection), we propose the idea that "greenbeard" effects are relevant to explaining some cooperative behaviors in cancer. Also, we discuss the possibility that malignant cooperative cells express or co-opt cooperative traits normally expressed by healthy cells. We provide examples where considerations of these processes could help understand tumorigenesis and metastasis and argue that this framework provides novel insights into cancer biology and potential strategies for cancer prevention and treatment.},
}