Differences in Diet Between Six Neighbouring Groups of Vervet Monkeys

Integrating culture into primate conservation

Primates exhibit the richest cultural repertoire among animal taxa, spanning foraging, communication, sociality and tool use. Understanding the cultural behaviours of primates has strongly influenced the study of animal behaviour and challenged traditional views that culture is exclusive to humans. With nearly 60% of primate species endangered owing to human-driven habitat changes, recent calls have emerged to integrate cultural diversity into conservation strategies. However, the integration of culture into primate conservation requires careful planning to avoid misallocation of resources or skewed conservation priorities. Our review reveals that studies on primate culture are limited to less than 3% of extant species, largely owing to taxonomic and methodological biases favouring long-term observations in protected habitats. We propose that including culture in conservation policies can broaden the scope of research, fostering more inclusive conservation agendas that address taxa with diverse habitats and underexplored cultural traits. Furthermore, anthropogenic habitat changes can both erode and foster cultural behaviours, emphasizing the need for context-specific conservation strategies. We suggest that recognizing cultural traits in conservation frameworks may enhance the resilience of primate populations in changing environments. This approach promises a more comprehensive and equitable allocation of conservation efforts, preserving both the biological and cultural diversity of primates.This article is part of the theme issue 'Animal culture: conservation in a changing world'.

Focal vs. fecal: Seasonal variation in the diet of wild vervet monkeys from observational and DNA metabarcoding data

Assessing the diet of wild animals reveals valuable information about their ecology and trophic relationships that may help elucidate dynamic interactions in ecosystems and forecast responses to environmental changes. Advances in molecular biology provide valuable research tools in this field. However, comparative empirical research is still required to highlight strengths and potential biases of different approaches. Therefore, this study compares environmental DNA and observational methods for the same study population and sampling duration. We employed DNA metabarcoding assays targeting plant and arthropod diet items in 823 fecal samples collected over 12 months in a wild population of an omnivorous primate, the vervet monkey (Chlorocebus pygerythrus). DNA metabarcoding data were subsequently compared to direct observations. We observed the same seasonal patterns of plant consumption with both methods; however, DNA metabarcoding showed considerably greater taxonomic coverage and resolution compared to observations, mostly due to the construction of a local plant DNA database. We found a strong effect of season on variation in plant consumption largely shaped by the dry and wet seasons. The seasonal effect on arthropod consumption was weaker, but feeding on arthropods was more frequent in spring and summer, showing overall that vervets adapt their diet according to available resources. The DNA metabarcoding assay outperformed also direct observations of arthropod consumption in both taxonomic coverage and resolution. Combining traditional techniques and DNA metabarcoding data can therefore not only provide enhanced assessments of complex diets and trophic interactions to the benefit of wildlife conservationists and managers but also opens new perspectives for behavioral ecologists studying whether diet variation in social species is induced by environmental differences or might reflect selective foraging behaviors.

Distribution, diet, and trophic level of Arvicanthis abyssinicus and Tachyoryctes splendens around the area of recently extinct Ethiopian Wolf Canis simiensis on Mount Guna, northwestern Ethiopia

Abyssinian Grass Rats Arvicanthis abyssinicus and Common Mole Rats Tachyoryctes splendens are preyed upon by the Ethiopian Wolf Canis simiensis. The aim of this study was to assess distribution, diet and trophic level of Arvicanthis abyssinicus and Tachyoryctes splendens on Mount Guna, where wolves have recently become extinct. Rodents were captured with Sherman trap and identified, and samples were taken to Debre Tabor University for dissection and diet analysis via microscopy examination of stomach contents. 110 A. abyssinicus and 52 T. splendens were captured from the study area, and the estimated population sizes of A. abyssinicus and T. splendens in Mt. Guna computed by Peterson-Lincoln Index were 1,364 and 416, respectively. In addition, 379 burrows (203 of A. abyssinicus and 176 of T. splendens) were counted. Both species were observed to consume plants and arthropods, with plants predominant. We recommend that intensive studies should be carried out to determine the effects of rodent communities upon Mt. Guna afroalpine and subafroalpine ecosystems.

Meat eating by nonhuman primates: A review and synthesis

Most nonhuman primates prey on vertebrates. Meat-eating, defined as ingestion of vertebrate tissue, occurs in 12 families, ≥39 genera, and ≥89 species. It is most common in capuchins (Cebus and Sapajus spp.), baboons (Papio spp.), bonobos (Pan paniscus), and chimpanzees (Pan troglodytes) and modestly common in blue monkeys (Cercopithecus mitis), callitrichids (Callithrix spp. and Saguinus spp.), and squirrel monkeys (Saimiri spp.). It is uncommon in other cercopithecines, rare in other haplorhines and in lemurs, and virtually absent in colobines. Birds are the prey class eaten by the most species (≥53), followed by reptiles (≥48), amphibians (≥38), mammals (≥35), and fish (≥7). Major hypotheses for the importance of meat eating are that it is (1) mainly an energy source, especially (1a) when plant-source foods (PSFs) with high energy return rates are scarce (energy shortfall hypothesis); (2) mainly a protein source; and (3) mainly a source of micronutrients scarce in PSFs. Meat eating bouts sometimes provide substantial energy and protein, and some chimpanzees gain substantial protein from meat monthly or annually. However, meat typically accounts for only small proportions of feeding time and of total energy and protein intake, and quantitative data are inconsistent with the energy shortfall hypothesis. PSFs and/or invertebrates are presumably the main protein sources, even for chimpanzees. Support is strongest for the micronutrient hypothesis. Most chimpanzees eat far less meat than recorded for hunter-gatherers, but the highest chimpanzee estimates approach the lowest for African hunter-gatherers. In fundamental contrast to the human predatory pattern, other primates only eat vertebrates much smaller than they are, tool-assisted predation is rare except in some capuchins and chimpanzees, and tool use in carcass processing is virtually absent. However, harvesting of small prey deserves more attention with reference to the archaeological and ethnographic record.

Does culture shape hunting behavior in bonobos?

New evidence that neighboring communities of bonobos hunt different prey species, despite extensive overlaps in where they live and hunt, is difficult to explain without invoking cultural factors.

Population genetic structure and evolutionary history of Bale monkeys (Chlorocebus djamdjamensis) in the southern Ethiopian Highlands

Background

Species with a restricted geographic distribution, and highly specialized habitat and dietary requirements, are particularly vulnerable to extinction. The Bale monkey (Chlorocebus djamdjamensis) is a little-known arboreal, bamboo-specialist primate endemic to the southern Ethiopian Highlands. While most Bale monkeys inhabit montane forests dominated by bamboo, some occupy forest fragments where bamboo is much less abundant. We used mitochondrial DNA (mtDNA) sequences to analyse the genetic structure and evolutionary history of Bale monkeys covering the majority of their remaining distribution range. We analysed 119 faecal samples from their two main habitats, continuous forest (CF) and fragmented forests (FF), and sequenced 735 bp of the hypervariable region I (HVI) of the control region. We added 12 orthologous sequences from congeneric vervets (C. pygerythrus) and grivets (C. aethiops) as well as animals identified as hybrids, previously collected in southern Ethiopia.

Results

We found strong genetic differentiation (with no shared mtDNA haplotypes) between Bale monkey populations from CF and FF. Phylogenetic analyses revealed two distinct and highly diverged clades: a Bale monkey clade containing only Bale monkeys from CF and a green monkey clade where Bale monkeys from FF cluster with grivets and vervets. Analyses of demographic history revealed that Bale monkey populations (CF and FF) have had stable population sizes over an extended period, but have all recently experienced population declines.

Conclusions

The pronounced genetic structure and deep mtDNA divergence between Bale monkey populations inhabiting CF and FF are likely to be the results of hybridization and introgression of the FF population with parapatric Chlorocebus species, in contrast to the CF population, which was most likely not impacted by hybridization. Hybridization in the FF population was probably enhanced by an alteration of the bamboo forest habitat towards a more open woodland habitat, which enabled the parapatric Chlorocebus species to invade the Bale monkey's range and introgress the FF population. We therefore propose that the CF and FF Bale monkey populations should be managed as separate units when developing conservation strategies for this threatened species.

Electronic supplementary material

The online version of this article (10.1186/s12862-018-1217-y) contains supplementary material, which is available to authorized users.

Dietary Variation in Diana Monkeys (Cercopithecus diana): The Effects of Polyspecific Associations

Establishing dietary central tendencies and extremes remains an important goal of primate research. While habitat differences and spatial discontinuity are well-documented contributors to dietary variation, other factors including polyspecific associations may significantly impact diet through changes in strata use and/or increased feeding competition. Here, we examine polyspecific association with closely related species as a source of dietary variation in a rain forest primate. Diana monkeys (Cercopithecus diana) in Côte d'Ivoire's Taï Forest frequently participate in mixed-species groups. We use data collected over a 5-year period on 4 Diana monkey groups to examine how association affects group diets. Groups exhibited significant differences in association rates with other guenon species, but this minimally influenced diet when food categories (fruit, invertebrates, leaves) were compared: diet overlap of 4 groups across the study period ranges from 90.8 to 98.1%. Examination of species composition within food categories is more revealing: intergroup dietary overlap decreases to 69.8-79.4% across the study period when comparing species contributing to total frugivory and folivory. These data support earlier findings that Diana monkeys maintain fruit-rich diets by competitively excluding sympatric congeners while highlighting that even selective frugivores such as Diana monkeys may exhibit remarkable dietary flexibility. Our study underscores the fact that broad categorical labels can obscure significant dietary differences.