Biology subjects

Dal Pesco, F.

Publications and source records attributed to Dal Pesco, F..

10 recordsLinked to original sources

bioRxiv2026

Copulation calls indicate fertility but do not reflect female mate competition in wild Guinea baboons

Across different modalities, signals play a core role in attracting mates and influencing mating success. In several non-human primate species, females produce calls during mating that are thought to promote male competition over receptive females. The extent to which social system characteristics modulate the function of copulation calls remains less clear. We studied copulation calls in wild Guinea baboons (Papio papio), who live in a multilevel society structured around units in which females associate and mate almost exclusively with a single male. We hypothesised that females use copulation calls as an indirect form of mate competition, with competition increasing in larger units. In addition, we hypothesised that females are more likely to mate again after calling. We analysed 6116 copulations between 2014 and 2025, involving 99 reproductively active females and 78 subadult and adult males. Females produced copulation calls in 72.7% of copulations, with large inter-individual variation. Neither unit size nor its interaction with the female's swelling size or the presence of simultaneously receptive females affected the probability of calling. A survival analysis with a subset of the data (2353 copulations) revealed no effect of calling on the latency to the next mating. Our results render the hypothesis that female Guinea baboons use calls in indirect mate competition unlikely. Yet, the probability of calling varied with sexual swelling size, suggesting that calls signal female fertility. Possibly, Guinea baboon copulation calls represent an evolutionary remnant, no longer under selective pressure, and can be considered index signals of female fertility.

animal behavior and cognition↗

bioRxiv2026

Post-mortem infant-directed behaviours in wild Guinea baboons

The growing field of comparative thanatology aims to shed light on how and why the understanding of death evolved. Observations across different nonhuman primate species have reported care-taking behaviour of dead infants, but also cannibalism. Various hypotheses have been put forward to explain these infant-directed behaviours, ranging from responses to infantile cues to an understanding of death. To aid comparative analyses and test some of these hypotheses, we report behaviours directed at dead infants in a wild population of Guinea baboons (Papio papio) living in the Niokolo-Koba National Park, Senegal. During 12 years of field observations (2014-2025), 67 infants died before reaching 1 year of age. In 4 cases, we could not establish when the infants had died because the field station was closed due to the COVID-19 pandemic. In 22 of the remaining 63 cases, mothers, but occasionally also other group members, carried, protected, groomed, and dragged dead infants. In 6 cases, cannibalism occurred. None of the mothers expressed any signs of emotional distress in response to infant death. We suggest that a concept of death in Guinea need not be invoked to explain the observed behaviours. Instead, selection appears to have favoured post-mortem caretaking behaviours to avoid abandoning an infant that might temporarily be unresponsive. The lack of infant responses to maternal behaviour and the disintegration of the corpse may drive the transition from perceiving the infants as an object that evokes caretaking to one that resembles food, which ultimately facilitates occurrences of cannibalism.

animal behavior and cognition↗

bioRxiv2026

Maternal style does not predict infant growth and survival in wild Guinea baboons

Primate infants depend on their mothers for nursing, transportation, and survival, but also benefit from other behaviours such as contact, protection, and the mother serving as a model for social learning. During infancy, variation in maternal care ("maternal style") can have profound consequences for infant development and survival. We investigated the link between maternal style and infant growth and survival in wild Guinea baboons (Papio papio). This species lives in a tolerant social system with female-biased dispersal. We used data from N = 80 infants to assess variation in maternal style. The final statistical models comprised data from N = 50 infants for the growth analysis based on Parallel Laser Photogrammetry (PLP) measures of forearm length, and N = 63 infants for the survival analysis. To account for heterogeneity in data, we applied a recently established statistical framework that controls for variation in maternal behaviour with infant age. We found only moderate variation among mothers and no evidence for a link between maternal style and infant growth or survival. Neither infant sex, maternal age, nor NDVI variation, a measure later shown to be a poor indicator of food availability, predicted infant growth or survival. We suspect that, in this population living in a habitat with high carrying capacity, disease and predation have greater effects on infant growth and survival than maternal behaviour. Future studies should consider the interplay between infant behaviour and maternal responses in greater detail to better understand variation in early social development.

animal behavior and cognition↗

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↗

bioRxiv2024

Meat transfers follow social ties in the multi-level society of Guinea baboons but are not related to male reproductive success

In human foraging societies, hunting skill is often interpreted as a signal of male quality linked to his reproductive success through his ability to provision his family and community. Similarly, in some bird and insect species, males offer their mates food to indicate their quality as a provider. Among non-human primates, however, the relationship between meat sharing and reproductive success is underexplored, leaving the evolutionary origins of this phenomenon unresolved. Guinea baboons (Papio papio) are a promising model to investigate whether meat sharing signals male quality, since females choose their mates, have been shown to rely on males to catch and share prey, and are responsive to male foraging skill. We combined records of 109 meat-eating events with nine years of behavioural data to test whether males who more frequently acquired and shared meat with females had more females in their social units for longer. Contrary to our predictions, we found no evidence that females preferred males who acquired or shared meat more frequently, suggesting that meat acquisition does not function as a signal of male quality in Guinea baboons. One explanation may be the relatively low frequency of meat-eating events. Another is that females are less dependent on males for meat than previously reported. Our results revealed that nearly half (41%) of female meat intake originated from sources other than her unit male, including the first documented cases of female prey capture (11% of events). Thus, females likely apply other, more pertinent, criteria in mate choice.

animal behavior and cognition↗

bioRxiv2024

Increased female competition for males with enhanced foraging skills in Guinea baboons

Recognizing skillful group members is crucial for making optimal social choices. Whether and how nonhuman animals attribute skill to others is still debated. Using a lever-operated food box, we enhanced the foraging skill of a single male (the specialist) in one zoo housed and two wild groups of Guinea baboon (Papio papio). We measured group members behav-ioral responses before, during, and after our manipulation to reveal whether they focused on the outcome of the males actions or changed their assessment of his long-term value. During the manipulation, females in the specialists unit, but not the wider group, competed over ac-cess to the specialist - increasing their grooming of him tenfold and aggression near him four-fold. Both behaviors were predicted by the amount each female ate from the food box and re-turned to baseline within two weeks of its removal. This behavioral pattern supports an out-come-based assessment where females responded to male-provided benefits (utility) rather than attributing competence (value). TeaserGuinea baboon females monopolize males in relation to their current perceived utility.

animal behavior and cognition↗

bioRxiv2023

Overcoming Pitfalls when Estimating Variation in Parental Investment: A Simulation Study

1. BackgroundIn many animal species, parents allocate resources to enhance offspring survival and thereby reproductive success ( parental investment). Parental care behaviors are a crucial part of parental investment, and one critical question in behavioral ecology is to which degree variation in parental care affects offspring development and survival. Crucially, parental care behaviors vary with offspring age, which creates non-trivial problems for statistical analyses, specifically when sampling is incomplete or biased. 2. MethodsWe conducted a simulation study to illustrate the problem when analyzing average parental care behaviors while not correcting for offspring age ( conventional approach), and propose a modeling approach to correct for offspring age and sampling biases. We simulated a set of different scenarios, varying with regard to sample size, sampling scheme, and variation in parental behavior. To model parent behavior as a function of offspring age, we fitted a Generalized Linear Mixed Model to each simulated data set. We included offspring age as a fixed effect and extracted Best Linear Unbiased Predictors (BLUPs) for the random intercept of parent identity. These BLUPs represent the parental behavior corrected for offspring age. Finally, we assessed how our proposed modeling approach compares to the conventional approach. 3. ResultsThe proposed modeling approach was superior to the conventional approach. More specifically, the conventional approach clearly overestimated the variation between parents, and even diagnosed appreciable variation when there was none in the simulated data. This bias was exacerbated in incomplete or unbalanced sampling schemes. 4. Conclusion.Our simulation study clearly demonstrates the necessity of correcting for offspring age in analyses of parental behavior. We strongly suggest including random slopes of offspring age within parent-offspring dyads, because doing so can reveal parent-specific trajectories of the modeled behavior against offspring age. Our approach allows for the inclusion of further categorical and continuous predictor variables that may affect parental behavior, such as parity or ecological conditions. In summary, the proposed modeling approach has several advantages over conventional methods.

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↗