Biology subjects

Warutere, J. K.

Publications and source records attributed to Warutere, J. K..

7 recordsLinked to original sources

bioRxiv2026

Activity budgets, social behavior, and fitness outcomes associated with a baboon group fusion

Many primates exhibit female philopatry and live in stable, female-bonded groups, where females are seldom exposed to novel same-sex conspecifics. Permanent group fusions are unique in bringing unfamiliar female conspecifics together but are rarely documented in these populations. We present a case study on a fusion of two groups from a hybrid population of baboons (Papio cynocephalus x P. anubis ) living in the Amboseli basin of Kenya. We compared the behavior of eight adult females after the fusion to the behavior of females in groups that had not fused and compared pre- and post-fusion fitness outcomes. Following the fusion, the group's activity budget and patterns of agonistic interactions were typical for the study population. Females preferred familiar grooming partners for a short period following the fusion; however, after three months, female grooming patterns were comparable to other groups, indicating rapid social integration. Females from the smaller pre-fusion group were lower ranking than females from the larger group. The fusion occurred following increased human-induced mortality in one of the two groups. From our limited sample, we observed no detectable fitness-related costs of fusion in terms of birth rates or offspring survival, while adult female mortality was low following the fusion. These results demonstrate the flexibility of female baboons in navigating exposure to novel same-sex conspecifics despite a species-typic pattern of female philopatry. Our results support previous research indicating that group fusions most likely occur when groups are too small to retain adult males, defend against predators, or compete with other groups.

animal behavior and cognition↗

bioRxiv2025

Group social conditions and environment predict foraging behavior in wild baboons

For group-living animals, conditions in the physical and social environments are closely linked to foraging outcomes, but the nature and causal direction of many aspects of these relationships remain unclear. Here, we use long-term data from a well-studied population of wild baboons in Amboseli, Kenya, to examine how group-level social traits (group size and social network density) and climate variables (rainfall and temperature) are linked to two types of foraging outcomes for adult female baboons: (i) foraging-related time budgets and (ii) diet composition (time spent on fallback foods, such as grass corms, versus high-energy foods). We find that rainfall and temperature interact to predict multiple foraging outcomes: more rainfall is associated with more time spent feeding, less time spent walking without feeding, and more feeding time spent on grass corms, but this influence is more pronounced in hotter years than in cooler years. Females in intermediate-sized groups spend more time walking without feeding than those in other groups, but group size does not significantly predict other foraging-related outcomes (i.e., time spent feeding or diet composition). We also find that females in groups with denser social networks spend less time feeding, and less time feeding on grass corms, than those in sparser networks. However, in a preliminary causal analysis meant to further explore this result, we find support for the hypothesis that this relationship is driven by effects of foraging on social behavior, as opposed to effects of network density on foraging: more time spent eating grass corms leads to lower social network density and more time spent feeding. Our results show how the social and the physical environments are linked to foraging outcomes, and highlight the importance of future studies of their pattern and mechanism.

ecology↗

bioRxiv2025

Early-life paternal relationships predict adult female survival in wild baboons

Parent-offspring relationships can have profound effects on offspring behavior, health, and fitness in adulthood. These effects are strong when parents make heavy investments in offspring care. However, in some mammals, including several species of carnivores, rodents, and primates, fathers live and socialize with offspring, but paternal care per se is subtle or indirect. Do these limited father-offspring relationships also affect later-life outcomes for offspring? Working in a well-studied baboon population where males contribute little direct offspring care, we found that juvenile female baboons who had stronger paternal relationships, or who resided longer with their fathers, led adult lives that were 2-4 years longer than females with weak or short paternal relationships. This pattern did not differ between females who experienced high versus low levels of early-life adversity; hence, paternal relationships were equally protective in both harsh and benign early environments. Males relationships were strongest with juvenile females they were most likely to have sired and when males had few mating opportunities. Hence, father-daughter relationships may be constrained by male mating effort. Because survival predicts female fitness, fathers and their daughters may experience selection to engage socially and stay close in daughters early lives.

evolutionary biology↗

bioRxiv2024

High early lactational synchrony within baboon groups predicts increased infant mortality

Female-female competition may be particularly acute when many females in the same social group have dependent young at the same time, with potential negative consequences for offspring survival. Here, we used more than four decades of data on wild baboons (Papio sp.) in Amboseli, Kenya, to examine the effects of early lactational synchrony (the proportion of females in a group with an infant <90 days old) on female-female agonistic interactions and infant survival. Because early lactation is energetically demanding for mothers and high-risk for infants, we expected early lactational synchrony to intensify both female-female aggression and maternal association with males, who can buffer infants from conspecific harassment. In support of these predictions, when early lactational synchrony was high, new mothers initiated more agonistic contests. Further, high-ranking females increased their time associating with adult males, which may limit the ability of low-ranking females to receive male protective services and may have downstream consequences for female foraging efficiency. Finally, high early lactational synchrony strongly predicted infant mortality. This association may result from both aggression among adult females and infanticidal behavior by peripubertal females. Our findings provide evidence that synchronous reproduction alters competitive regimes and compromises reproductive outcomes even in nonseasonal breeders.

animal behavior and cognition↗

bioRxiv2022

Five decades of data yield no support for adaptive biasing of offspring sex ratio in wild baboons (Papio cynocephalus)

Over the past 50 years, a wealth of testable, often conflicting, hypotheses have been generated about the evolution of offspring sex ratio manipulation by mothers. Several of these hypotheses have received support in studies of invertebrates and some vertebrate taxa. However, their success in explaining sex ratios in mammalian taxa, and especially in primates, has been mixed. Here, we assess the predictions of four different hypotheses about the evolution of biased offspring sex ratios in the well-studied baboons of the Amboseli basin in Kenya: the Trivers-Willard, female rank enhancement, local resource competition, and local resource enhancement hypotheses. Using the largest sample size ever analyzed in a primate population (n = 1372 offspring), we test the predictions of each hypothesis. Overall, we find no support for adaptive biasing of sex ratios. Offspring sex is not consistently related to maternal dominance rank or biased towards the dispersing sex, nor it is predicted by group size, population growth rates, or their interaction with maternal rank. Because our sample size confers power to detect even subtle biases in sex ratio, including modulation by environmental heterogeneity, these results suggest that adaptive biasing of offspring sex does not occur in this population.

evolutionary biology↗

bioRxiv2021

Synchrony and idiosyncrasy in the gut microbiome of wild primates

Human gut microbial dynamics are highly individualized, making it challenging to link microbiota to health and to design universal microbiome therapies. This individuality is typically attributed to variation in host genetics, diets, environments, and medications, but it could also emerge from fundamental ecological forces that shape microbiota more generally. Here we leverage extensive gut microbial time series from wild baboons--hosts who experience little interindividual dietary and environmental heterogeneity--to test whether gut microbial dynamics are synchronized across hosts or largely idiosyncratic. Despite their shared lifestyles, baboon microbiome dynamics were only weakly synchronized. The strongest synchrony occurred among baboons living in the same social group, likely because group members range over the same habitat and simultaneously encounter the same sources of food and water. However, this synchrony was modest compared to each hosts personalized dynamics. Indeed, host-specific factors, especially host identity, explained 10 times the deviance in longitudinal microbial dynamics, compared to factors shared across hosts. These results contribute to mounting evidence that highly idiosyncratic gut microbiomes are not an artifact of modern human environments, and that synchronizing forces in the gut microbiome (e.g., shared environments, diets, and microbial dispersal) are often not strong enough to overwhelm drivers of microbiome personalization, including host genetics, priority effects, horizontal gene transfer, and functional redundancy.

ecology↗

bioRxiv2021

Selection against admixture and gene regulatory divergence in a long-term primate field study

Admixture has profoundly influenced evolution across the tree of life, including in humans and other primates1,2. However, we have limited insight into the genetic and phenotypic consequences of admixture in primates, especially during its key early stages. Here, we address this gap by combining 50 years of field observations with population and functional genomic data from yellow (Papio cynocephalus) and anubis (P. anubis) baboons in Kenya, in a longitudinally studied population that has experienced both historical and recent admixture3. We use whole-genome sequencing to characterize the extent of the hybrid zone, estimate local ancestry for 442 known individuals, and predict the landscape of introgression across the genome. Despite no major fitness costs to hybrids, we identify signatures of selection against introgression that are strikingly similar to those described for archaic hominins4-6. These signatures are strongest near loci with large ancestry effects on gene expression, supporting the importance of gene regulation in primate evolution and the idea that selection targeted large regulatory effects following archaic hominin admixture7,8. Our results show that genomic data and field observations of hybrids are important and mutually informative. They therefore demonstrate the value of other primates as living models for phenomena that we cannot observe in our own lineage.

evolutionary biology↗