Biology subjects

Trede, F.

Publications and source records attributed to Trede, F..

4 recordsLinked to original sources

bioRxiv2025

Nested Male Reproductive Strategies in a Tolerant Multilevel Primate Society

Male reproductive success varies within populations. Models explaining reproductive skew emphasise dominance, yet the determinants of male reproductive success in egalitarian societies remain poorly understood. Using nine years of behavioural and genetic data from five parties, we investigated male reproductive monopolisation in wild Guinea baboons (*Papio papio*), an egalitarian multilevel society with one-male "units" nested within "parties" and low male-male contest competition. Genetic analyses showed 93% of the 71 infants were sired by the female's "unit male", with extra-unit paternities consistent with limited control models. Reproduction was distributed among multiple unit males, resulting in low reproductive skew at the party level, with top males siring 23-40% of offspring, well below levels in despotic species. Female takeovers were rare, suggesting male restraint. Among prime-aged males, the number of unit females was only weakly positively associated with dominance ratings. Prime-age predicted reproductive success better than dominance. Non-prime-aged males had fewer females across dominance ratings. In conclusion, male Guinea baboons' reproductive potential is shaped less by dominance than by age and stable associations with females, who play an active role in inter-sexual relationships. These results emphasise the need to move beyond frameworks focused solely on dominance-based mechanisms and to consider species-specific social organisation.

animal behavior and cognition↗

bioRxiv2025

Disparate social structures are underpinned by distinct social rules across a primate radiation

Over six decades of research on wild baboons and their close relatives (collectively, the African papionins) have uncovered substantial variation in their behavior and social systems. While most papionins form discrete social groups (single-level societies), a few others form small social units that are nested within larger supergroups (multi-level societies). These two systems are generally thought to be qualitatively distinct, but data from wild populations increasingly suggest that there may be areas of overlap. To quantify this potential gradient in social structure, a more systematic, comparative analysis is needed. Here, we constructed a database of behavioral and demographic records spanning 135 group-years, 28 social groups, 13 long-term field studies, and 11 species to quantify variation in grooming network structure, and identify the individual and dyadic properties (e.g., kinship and social status effects) that underlie this variation. Consistent with accumulating observations in the field, the single-level species could be divided into two categories: cohesive and cliquish. Cohesive single-level networks were dense, kin-biased, and moderately rank-structured, while cliquish single-level networks were more differentiated, slightly more kin-biased, and strongly rank-structured. As expected, multi-level networks were very modular and shaped by females ties to specific dominant males but varied in their kin biases. Taken together, these data suggest that (i) kin and rank biases are widespread but vary in their strength; (ii) male-centered subgroups are exclusive to multi-level systems; and (iii) increases in network modularity can emerge in response to heightened nepotism and male-centered clustering. SIGNIFICANCE STATEMENTWhat forces explain variation in primate societies? While kinship and dominance shape the social lives of many of our close relatives, it is unclear how their effects differ across species. Using a new database comprising decades of field research, we found that baboons and their close relatives fell into three general patterns: one in which groups were cohesive, kin-biased, and moderately rank-biased, another in which groups were more cliquish and nepotistic, and a third in which groups were divided into clusters centered on dominant males. Distinct primate societies may thus reflect differences in the strength of females nepotistic biases and the degree of males social influence.

animal behavior and cognition↗

bioRxiv2022

MALE-MALE SOCIAL BONDING, COALITIONARY SUPPORT AND REPRODUCTIVE SUCCESS IN WILD GUINEA BABOONS

Male-male bonds may confer substantial fitness benefits. The adaptive value of these relationships is often attributed to coalitionary support, which aids in rank ascension and female defence, ultimately resulting in greater reproductive success. We investigated the link between male-male sociality and both coalitionary support and reproductive success in wild Guinea baboons. This species lives in a tolerant multi-level society with reproductive units comprising a male and 1-6 females at the core. Males are philopatric, form differentiated, stable, and equitable affiliative relationships ( strong bonds) with other males, and lack a clear rank hierarchy. Here, we analysed behavioural and paternity data for 30 males and 50 infants collected over four years in the Niokolo-Koba National Park, Senegal. Strongly bonded males supported each other more frequently during conflicts, but strong bonds did not promote reproductive success. Instead, males that spent less time socializing with other males were associated with a higher number of females and sired more offspring. Notably, reproductively active males still maintained bonds with other males, but adjusted their social investment in relation to life-history stage. Long-term data will be needed to test if the adaptive value of male bonding lies in longer male tenure and/or in promoting group cohesion.

animal behavior and cognition↗

bioRxiv2020

Vocal convergence in the multi-level society of Guinea baboons

The extent to which nonhuman primate vocalizations are amenable to modification through experience is relevant for understanding the substrate from which human speech evolved. We examined the vocal behaviour of Guinea baboons, Papio papio, ranging in the Niokolo Koba National Park in Senegal. Guinea baboons live in a multi-level society, with units nested within parties nested within gangs. We investigated whether the acoustic structure of grunts of 27 male baboons of two gangs varied with party/gang membership and genetic relatedness. Males in this species are philopatric, resulting in increased male relatedness within gangs and parties. Grunts from members were more similar within than across social levels (N = 351 dyads for comparison within and between gangs, and N = 169 dyads within and between parties), but the effect sizes were small. Yet, acoustic similarity did not correlate with genetic relatedness, suggesting that higher amounts of social interactions rather than genetic relatedness promote the observed vocal convergence. We consider this convergence a result of sensory-motor integration and suggest this to be an implicit form of vocal learning shared with humans, in contrast to the goal-directed and intentional explicit form of vocal learning unique to human speech acquisition.

animal behavior and cognition↗