Biology subjects

Cant, M. A.

Publications and source records attributed to Cant, M. A..

9 recordsLinked to original sources

bioRxiv2025

Collective Self-Assessment in Banded Mongoose Intergroup Contests

Contests over resources are widespread in nature. To optimize outcomes, animals assess fighting abilities, deciding to escalate conflicts based on their own strength (self-assessment) or comparing their own strength with that of their rival (mutual assessment). While most research focuses on one-on-one (dyadic) contests, the assessment strategies employed by groups remain poorly understood. Mutual assessment is frequently assumed, as more information is thought to improve decision-making; however, this assumption has rarely been tested. Here we used a dataset spanning 23 years and 641 intergroup contests in a banded mongoose (Mungos mungo) population in Queen Elizabeth National Park, Uganda. Our results support a model of self-assessment: groups with many males tend to escalate conflicts regardless of the rival groups strength, thus contrasting the commonly held assumption that decisions during intergroup contests are made by mutual assessment. We suggest that assessing rival group strength during conflict could be disproportionately costly, compared with assessing own group strength, which can be done over longer time periods and is easier to obtain. Greater understanding of these dynamics can shed light on the drivers and escalation patterns of intergroup conflict across social species, including humans. Lay SummaryWhen two rival groups come together, what determines whether or not they fight? We found support for the hypothesis that banded mongoose groups escalate into physical fights based upon an estimation of their own groups strength, which we term collective self-assessment. We did not find evidence for a commonly held notion that groups compare their own groups strength with their rivals. Distinguishing between assessment strategies is intensively researched in contests between individuals but has rarely been applied to intergroup conflict. Here we applied the successful "assessment strategy framework" to group conflict, analyzing over 20 years of data from over 600 intergroup interactions. We suggest that collective self-assessment is employed because it is faster than mutual assessment, which offers an advantage in conflicts where time is of the essence.

animal behavior and cognition↗

bioRxiv2025

A landscape of intergroup conflict shapes den site choice in banded mongooses

BackgroundFor many social animals, intergroup conflict has major impacts on fitness and should therefore influence how groups navigate their environment. Yet most studies of group movement focus on the behaviour of single groups, usually foraging groups studied in isolation of all others. In many systems rival groups present both threats and opportunities, contributing to a landscape of intergroup conflict. This landscape could have a profound impact on group movement. MethodsHere we test how the potential for intergroup conflict influences movement decisions of wild cooperatively breeding banded mongooses, using 14 years of behavioural and GPS data. In this species, encounters between groups can present both risks (e.g. injury/mortality) and opportunities (e.g., extragroup mating). We expected that, to minimise risks and maximise rewards, the motivation to engage in conflict would depend on the groups state. Such that vulnerable groups (those that were babysitting young offspring) would select den sites closer to the core of their territory than groups without young offspring. ResultsWe found support for this pattern; non-babysitting groups were unusually risk prone choosing den locations in areas of frequent use by outgroups. During times of heightened recent conflict even choosing to den closer to the core of their rivals territory than their own. ConclusionsThese results suggest that groups of banded mongooses choose den sites that reflect not only the risks but also the potential rewards of defensive or competitive claims on space. Rival groups thus form an integral part of the social landscape shaping patterns of collective movement.

animal behavior and cognition↗

bioRxiv2025

Spend today or build for tomorrow? Kinship dynamics and the evolution of alternative helping strategies in cooperative breeders.

Cooperatively breeding animal groups are characterised by the presence of helpers, which assist breeders in raising offspring through a variety of behaviours, such as provisioning young or defence against predators. While these systems have been studied to investigate how costly forms of help can evolve, there is little theory explaining the considerable variation in helping strategies observed across such societies. Here, we use mathematical models to investigate the evolution of alternative helping strategies. Helpers in our models can allocate effort to immediate, short-term benefits or durable, long-term benefits. We find that allocation depends on the kinship dynamics within the group. Specifically, where helpers are more related to future breeders than current breeders, often because they themselves become the future breeder, our model typically predicts greater allocation to durable help. Conversely, immediate help is favoured when helpers are less related to future breeders than to current breeders. We use our model to explore how demographic features impact kinship dynamics within the group, identify which factors select for immediate versus durable help, and which amplify conflict between breeders and helpers over helping strategies. The model is a first step towards explaining variation in types of help observed among cooperatively breeding societies.

evolutionary biology↗

bioRxiv2025

Predicting kinship dynamics during pre- and post reproductive life stages

Individuals relatedness to their groups often changes with age, potentially favouring age-linked trends in social behaviours, and these kinship dynamics have been invoked to explain the evolution of life history traits such as early reproductive cessation and post-reproductive helping. While models showed that simple demographic parameters (e.g., the rates of male and female philopatry vs dispersal, and of local vs non-local mating) suffice to predict the patterns of kinship dynamics breeders experience, they make the unrealistic assumptions that survival and fecundity are age-independent, thus fail to capture the full complexity of kinship dynamics. In particular, they cannot consistently predict how individuals relatedness to their groups should change during their pre- and post-reproductive phases. Here, we extend existing models of kinship dynamics to allow any age-linked changes in mortality and fecundity of both sexes. We describe the new model, and demonstrate its improved predictive power, by comparing the observed kinship dynamics of the killer whales to the predictions of the previously available models (assuming constant mortality and fecundity) and of our new model (considering any observed age-specific survival and fecundity). We show the new model better predicts the data, successfully capturing the observed three-stage female kinship dynamics: an individuals relatedness to her group decreases initially while juvenile, increases across reproductive lifespan, and decreases again during post-reproductive life. These predictions demonstrate the power of our model in generating new insights into the theory of social life history evolution (e.g., explaining why post-reproductive lifespan evolved yet are constrained).

evolutionary biology↗

bioRxiv2024

Banded mongooses discriminate relatedness and MHC diversity in unfamiliar conspecifics

Olfactory cues are critical in mammalian social communication, conveying fitness-relevant information such as relatedness, genetic quality, and compatibility. Recognizing kin through scent can help avoid inbreeding depression and guide nepotistic behaviors, enhancing both direct and indirect fitness. While many species use familiarity to identify relatives, others rely on phenotype matching, where animals assess genetic similarity by comparing their own genetically determined odor with that of others. In banded mongooses, synchronized breeding disrupts familiarity cues, increasing reliance on alternative mechanisms for kin discrimination and mate selection. We tested whether banded mongooses use odors to assess genetic diversity and relatedness based on (1) major histocompatibility complex (MHC) genotypes and (2) neutral microsatellite loci that reflect genetic diversity and relatedness. We found that individuals respond differently to odors from unfamiliar individuals based on MHC diversity and genetic relatedness. Specifically, individuals show more interest in less MHC diverse and less related unfamiliar conspecifics, suggesting odor cues are used to evaluate threat level of intruders or competitors. Genetic diversity had no impact on responses to odors and was not significantly associated with MHC diversity, implying that responses to MHC diversity did not result from an underlying correlation with over-all genetic diversity. We also found no effect of MHC similarity, which might be caused by the limited sample size for this analysis. Our findings show that MHC diversity might signal the genetic quality of individuals, but regions of the genome other than MHC may be used to assess relatedness. These findings provide the basis for future research on the involvement of the MHC and other genes in social communication in species where phenotype matching is likely to be advantageous.

animal behavior and cognition↗

bioRxiv2024

Sex-dependent influence of major histocompatibility complex diversity on fitness in a social mammal

Parasite infections affect males and females differently across a wide range of species, often due to differences in immune responses. Generally, females tend to have stronger immune defenses and lower parasite loads than males. The major histocompatibility complex (MHC) plays a crucial role in the adaptive immune response, and extensive research has explored how variation in this region influences infection and fitness outcomes. However, studies of sex-specific relationships between MHC variation and infection are scarce, perhaps because MHC genes are located on the autosomes, which are shared by both sexes. Here, we provide evidence of sexually antagonistic selection in a wild, group-living mammal--the banded mongoose. Using genetic and life history data collected from over 300 individuals across 25 years, we found that particularly MHC class I (MHC-I) but also MHC class II (MHC-II) diversity influence lifetime reproductive success differently in males and females. Specifically, higher MHC diversity is linked to increased fitness in males but decreased fitness in females. Furthermore, MHC diversity did not differ between the sexes, indicating an unresolved genetic sexual conflict. Our findings demonstrate that sexually antagonistic selection acts on the MHC and may operate across both MHC classes but differently. This study contributes to the growing body of evidence that sex is a significant factor in shaping host immunity and fitness.

evolutionary biology↗

bioRxiv2024

Characterization of both major histocompatibility complex classes in a wild social mammal: the banded mongoose

The major histocompatibility complexs (MHC) role in the vertebrate adaptive immune response and its exceptional polymorphism make it a key target for studying adaptive gene evolution. However, previous studies on carnivore MHC have mostly focused on populations which experienced a severe bottleneck or are of general conservation concern. Hence, sample sizes are often small and generalizations about MHC diversity are unreliable. Furthermore, studies often focus on one MHC class and do not cover the whole peptide binding groove of the MHC molecule. Here, we characterize MHC class I (MHC-I) exon 2 and 3, encoding both the 1- and 2-domain of the MHC-I molecule, as well as MHC-II DRB exon 2 for a large sample (N = 282-485) of a wild mammal of least conservation concern, the banded mongoose. We found that MHC-I generally showed higher allelic diversity and polymorphism compared to MHC-II, which is in line with findings in humans that show higher diversifying selection acting on MHC-I. However, MHC-I exon 3 showed the lowest diversity, possibly due to its different role in generating the peptide binding groove of the class I molecule compared to exon 2. Moreover, we found selection to act more strongly on MHC-I exon 2 (domain 1) than exon 3 (domain 2). Despite frequent inbreeding, phylogenetic comparative analysis showed banded mongooses to have MHC diversity levels comparable with other carnivores of least concern. Phylogenetic analysis indicated a longer evolutionary trajectory for MHC-II compared to MHC-I as well as species-specific gene duplication of nonclassical sequences of MHC-I clustering with classical sequences. Trans-species polymorphism was detected for nonclassical MHC-I sequences suggesting homology or convergent evolution for these genes. Our study is the first to characterize both MHC classes of a social, wild carnivore using a high throughput sequencing approach with a large sample size and thereby provides the basis for further investigation of MHC structure and function within the banded mongoose and other carnivores.

genetics↗

bioRxiv2023

Group size modulates kinship dynamics and selection on social traits

An individuals relatedness to its group may change with age due to demographic processes, and such kinship dynamics can shape age-linked social behaviors. Existing models, however, have focused almost exclusively on dispersal and mating, leaving the consequences of group size local variation unexplored. Here, we extend these models to incorporate such variation within a single, genetically connected meta-population. We then contrast predicted kinship dynamics and age-linked selection for helping/harming in coexisting smaller and larger groups in three typical social mammal systems characterized by distinct patterns of dispersal and mating, followed by exploring how group size local variation impacts female and male kinship dynamics across broader demographic contexts to clarify the population-genetic mechanisms. We show that, within the adult reproductive lifespans of these social systems, an individuals age-specific relatedness to others is higher, and changes faster (especially when younger), in smaller groups; consequently, smaller groups favor more extreme helping/harming (especially when younger) -- in social system with bi-sexual philopatry with non-local mating (e.g., whales) that favors female shifts from harming to helping with age (which explains the evolution of menopause and post-reproductive helping), such shifts are earlier in smaller groups. Further explorations suggest that, in a genetically connected population with group size local variation, group size effects on local relatedness are shaped by the relative strengths of ancestry dilution versus lineage coalescence, and kinship dynamics in a group reflect not only its local demographic conditions, but also those in coexisting groups of different size. Collectively, our study generates new insights into how female and male kinship dynamics emerge and vary under within-population group-size heterogeneity, and how such locally dynamic, varying kinship environments may help to explain variation in age-linked trends in social traits, such as the timing of menopause in social mammals.

evolutionary biology↗

bioRxiv2023

The Evolution of Democratic Peace

A major goal in evolutionary biology is to elucidate common principles that drive human and other animal societies to adopt either a warlike or peaceful nature. One proposed explanation for the variation in aggression between human societies is the democratic peace hypothesis. According to this theory, autocracies are more warlike than democracies because autocratic leaders can pursue fights for private gain. However, autocratic and democratic decision-making processes are not unique to humans and are widely observed across a diverse range of non-human animal societies. We use evolutionary game theory to evaluate whether the logic of democratic peace may apply across taxa; specifically adapting the classic Hawk-Dove model to consider conflict decisions made by groups rather than individuals. We find support for the democratic peace hypothesis without mechanisms involving complex human institutions and discuss how these findings might be relevant to non-human animal societies. We suggest that the degree to which collective decisions are shared may explain variation in the intensity of intergroup conflict in nature.

evolutionary biology↗