Biology subjects

De Moor, D.

Publications and source records attributed to De Moor, D..

5 recordsLinked to original sources

bioRxiv2024

The impact of kinship composition on social structure

The relatedness between group members is a potential driver of variation in social structure. Relatedness predicts biases in partner choice and formation of strong relationships among group members. As such, groups that differ in their percentage of non-kin dyads, i.e., in their kinship composition, should therefore differ in the structure of their social networks. Yet the relationship between kinship composition and social structure remains unclear. Here, we used long-term social and pedigree data from a population of rhesus macaques to investigate the relationship between kinship composition and the connectivity, cohesion, potential for transmission and social differentiation of the social networks of adult female macaques. We found no evidence that the social structure of groups composed of greater proportion of unrelated females differ from that of groups with a lower proportion of non-kin. To investigate this unexpected finding, we built agent-based models parameterised with the empirical data to further explore (1) the expected relationship between kinship composition and social structure and (2) why we did not find such a relationship in the empirical data. Agent-based models showed that kinship composition can influence social structure in populations similar to the one studied, but that this effect may only be detectable with a sample size even larger than ours (19 group-years) and with greater variance in kinship composition (proportion of non-kin varied between 0.830-0.922 in the empirical data). The relationship between kinship composition and social structure might be more apparent when comparing data from species that differ strongly in their social organisation, translating into marked differences in kinship composition. This further emphasises the importance of reporting existing and future kinship composition data to deepen our understanding of the evolution of sociality and highlights the potential of agent-based models to better understand empirical results.

animal behavior and cognition↗

bioRxiv2023

Socioecological drivers of injuries in female and male rhesus macaques (Macaca mulatta)

Competition over access to resources, such as food and mates, is believed to be one of the major costs associated with group living. Two socioecological factors suggested to predict the intensity of competition are group size and the relative abundance of sexually active individuals. However, empirical evidence linking these factors to injuries and survival costs is scarce. Here, we leveraged 10 years of data from free-ranging rhesus macaques where injuries inflicted by conspecifics are associated with a high mortality risk. We tested if group size and adult sex ratio predicted the occurrence of injuries and used data on physical aggression to contextualise these results. We found that males were less likely to be injured when living in larger groups, potentially due to advantages in intergroup encounters. Females, instead, had higher injury risk when living in larger groups but this was not explained by within-group aggression among females. Further, male-biased sex ratios predicted a weak increase in injury risk in females and were positively related to male-female aggression, indicating that male coercion during mating competition may be a cause of injuries in females. Overall, our results provide insights into sex differences in the fitness-related costs of competition and empirical evidence for long-standing predictions on the evolution of group living.

evolutionary biology↗

bioRxiv2023

MacaqueNet: big-team research into the biological drivers of social relationships

O_LIFor many animals, social relationships are a key determinant of fitness. However, major gaps remain in our understanding of the adaptive function, ontogeny, evolution, and mechanistic underpinnings of social relationships. There is a vast and ever-accumulating amount of social behavioural data on individually recognised animals, an incredible resource to shed light onto the biological basis of social relationships. Yet, the full potential of such data lies in comparative research across taxa with distinct life histories and ecologies. Substantial challenges impede systematic comparisons, one of which is the lack of persistent, accessible, and standardised databases. C_LIO_LIHere, we advocate for the creation of big-team collaborations and comparative databases to unlock the wealth of behavioural data for research on social relationships by introducing MacaqueNet (https://macaquenet.github.io/). C_LIO_LIAs a global collaboration of over 100 researchers, the MacaqueNet database encompasses data from 1981 to the present on 14 species and is the first publicly searchable and standardised database on affiliative and agonistic animal social networks. With substantial inter-specific variation in ecology and social structure and the first published record on macaque behaviour dating back to 1956, macaque research has already contributed to answering fundamental questions on the biological bases and evolution of social relationships. Building on these strong foundations, we believe that MacaqueNet can further promote collaborative and comparative research on social behaviour. C_LIO_LIWe believe that big-team approaches to building standardised databases, bringing together data contributors and researchers, will aid much-needed large-scale comparative research in behavioural ecology and beyond. We describe the establishment of MacaqueNet, from starting a large-scale collective to the creation of a cross-species collaborative database and the implementation of data entry and retrieval protocols. As such, we hope to provide a functional example for future endeavours of large-scale collaborative research into the biology of social behaviour. C_LI

animal behavior and cognition↗

bioRxiv2019

Female Assamese macaques bias their affiliation to paternal and maternal kin

Forming strong social bonds leads to higher reproductive success, increased longevity and/or increased infant survival in several mammal species. Given these adaptive benefits, understanding what determines partner preferences in social bonding is important. Maternal relatedness strongly predicts partner preference across many mammalian taxa. Although paternal and maternal kin share the same number of genes, and theoretically similar preferences would therefore be expected for paternal kin, the role of paternal relatedness has received relatively little attention. Here, we investigate the role of maternal and paternal relatedness for female bonding in Assamese macaques (Macaca assamensis), a species characterized by a relatively low male reproductive skew. We studied a wild population under natural conditions using extensive behavioural data and relatedness analyses based on pedigree reconstruction. We found stronger social bonds and more time spent grooming between maternal kin and paternal half-sisters compared to non-kin, with no preference of maternal over paternal kin. Paternally related and non-related dyads did not form stronger bonds when they had less close maternal kin available, however we would need a bigger sample size to confirm this. As expected given the low reproductive skew, bonds between paternal half-sisters closer in age were not stronger than between paternal half-sisters with larger age differences, suggesting that age similarity was not the mechanism by which paternally related individuals recognized each other. An alternative way through which paternal kin could get familiarized is mother- and/or father-mediated familiarity.

animal behavior and cognition↗

bioRxiv2019

Ecological and dietary differences between Ugandan chimpanzee communities with possible implications on tool use

Some East African chimpanzee (Pan troglodytes schweinfurthii) communities, such as the Sonso chimpanzees, display an unusually limited range of tool-use, but it remains unclear whether this is due to ecological and/or cultural factors. Information on ecological conditions and the diet of the Sonso chimpanzees in relation to neighbouring communities is needed. Here, we studied three adjacent communities in Budongo Forest (Sonso, Waibira, and Kamira), and the presumed core area of an undescribed community (Mwera), in the neighbouring Bugoma Forest. Through line-transects, we investigated (i) whether there were differences in food diversity and abundance between the communities home ranges; (ii) whether the home ranges differed in abundance of sticks and insect nests; and (iii) whether Sonso and Mwera chimpanzees differed in their diet (using faecal samples). Across communities, Sonso had the richest food availability and the lowest insect nest abundance. However, food availability in Mwera, Bugoma, was richer than Budongo communities that neighbour the Sonso territory, suggesting that there may be variation within Budongo. Data from faecal samples replicated our direct observations of food availability suggesting that Sonso chimpanzees had a broader diet than Mwera chimpanzees. This difference in foods availability may partially explain the Sonso chimpanzees lack of stick-tool-use, and low levels of insectivory. The tool repertoire of the other communities is currently unknown; however, we make predictions based on our ecological data. More detailed knowledge of small-scale variation in ecology within and between forest habitats may be important to advancing our understanding of the drivers of tool-use.\n\nSIGNIFICANCE STATEMENT - HIGHLIGHTED STUDENT PAPERTo advance our knowledge of the role of ecological factors in the emergence of tool use in chimpanzees, a nuanced understanding of the ecological conditions different chimpanzee communities experience is needed. We studied four Ugandan chimpanzee communities in two forests. One of these communities, Sonso, in the Budongo Forest, is well-known for its restricted range of tool types, including a total absence of stick use. Food diversity and abundance were highest, and stick tool use opportunities (abundance of sticks and insect nests) were lowest for the core-habitat of the Sonso chimpanzees in contrast to the other communities. We argue that ecological factors play a role in their unusual pattern of tool use, and make predictions about the expected types of tool use in the other communities based on their ecology. Thus, our study provides information that may help advance our understanding of how tool use arises under varied socioecological circumstances.

ecology↗