Figure - available from: Ecology and Evolution
This content is subject to copyright. Terms and conditions apply.
Source publication
• Multi‐level societies are complex, nested social systems where basic social groups (i.e., core units) associate in a hierarchical manner, allowing animals to adjust their group sizes in response to variables such as food availability, predation, or conspecific threat. These pressures fluctuate over time and examining the extent to which this vari...
Similar publications
Animals that occupy stable home ranges tend to unevenly exploit different areas in their efforts to find fitness-limiting resources, while also reducing the risks of intergroup conflict. Most analyses of these extrinsic forces identify their effects on movement paths and home range geometry, but not on the interaction of these responses or how move...
Citations
... For instance, snowshoe hares (Lepus americanus) increase their hair density in the winter to improve coat insulation, ultimately reducing foraging requirements and predator exposure (Balluffi-Fry et al., 2022, Kennah et al., 2023, Sheriff et al., 2009. Large bands of colobus monkeys (Colobus angolensis ruwenzorii) fission into smaller groups during the dry season (when food availability is low) to alleviate feeding competition; in the wet season, they remain in larger groups, likely to reduce their predation risk (Adams et al., 2021). Golden spiny mice (Acomys russatus) spend more time in torpor during the summer compared to the winter to conserve water in dry conditions (Levy et al., 2011). ...
Most environments exhibit predictable yearly changes, permitting animals to anticipate them. The hypothalamic–pituitary–adrenal (HPA) axis is a key physiological pathway that enables animals to cope with such changes. Monitoring glucocorticoid (the end products of the HPA axis) levels in wild animals throughout the year can improve our understanding of how this pathway responds to different conditions. For this study, we collected
18 months of data on two species of North American flying squirrels (Glaucomys sabrinus and G. volans) living in a
southern Ontario forest where temperature and food availability fluctuate dramatically throughout the year. These squirrels are active year-round, nest communally, and rely on scatter hoarded foods in the winter months. Flying squirrels have extremely high levels of free plasma cortisol relative to other mammals, but it is unknown how these levels are affected by environmental and reproductive factors. For both species, our goals were to (1)
validate an enzyme immunoassay (EIA) to measure their fecal glucocorticoid metabolite (FGM) concentrations and (2) assess yearly differences, seasonal changes, and the influence of sex, reproduction, and ambient temperature on FGM concentrations in each species. In the lab, we successfully validated the use of antibody 5α-pregnane-3β, 11β, 21-triol-20-one EIA for FGM analysis in both species. In the field, neither sex nor reproductive
status (breeding condition or not) were linked to FGM concentrations in either species. FGM concentrations were
higher in autumn compared to the spring and summer. There were no other seasonal differences. We discuss possible explanations for the autumn peak in FGM concentrations (increased energy expenditure and social nesting changes), as well as outline possible avenues for future research. Understanding how individuals and populations respond to environmental change is a critical goal in evolutionary ecology, particularly in the context of a rapidly changing Anthropocene.
... (i) Female associations when the alpha male is present/absent To examine the similarity of the dyadic association scores in the presence and absence of the alpha male, we used the cosine similarity metric to examine network similarity in primates [62,63]. The cosine similarity metric measures the similarity of associations between two networks and can consider the weight and presence of the associations [64]. ...
Social interactions ultimately impact health and fitness in gregarious mammals. However, research focusing on the strength of affiliative interactions has primarily been conducted on female philopatric species. Gorillas provide an interesting counterpoint to previous research as females emigrate multiple times throughout their lives. We compare female–female association strength, duration and consistency in wild mountain ( Gorilla beringei beringei ) and western gorillas ( Gorilla gorilla gorilla ). Additionally, we examine whether the alpha male influences female association strength and if these associations are an artefact of both females concurrently in spatial proximity of the alpha male. In this between-species comparison, female gorillas had differentiated association patterns that were consistent on average for 2 years. The alpha males did not influence female association strength, with associations being similar in his presence or absence. Finally, we found more variability in association patterns among mountain gorillas with higher average association scores and higher proportion of ‘preferred associates' than western gorillas. The rare dispersal pattern in the Gorilla genus may lead to greater flexibility in female association patterns than in species exhibiting female philopatry and strong kinship bonds. This may echo ancestral human society and provide new evidence to help us understand the evolution of modern human society.
This article is part of the theme issue ‘Cooperation among women: evolutionary and cross-cultural perspectives’.
The Colobines are a group of Afroeurasian monkeys that exhibit extraordinary behavioural and ecological diversity. With long tails and diverse colourations, they are medium-sized primates, mostly arboreal, that are found in many different habitats, from rain forests and mountain forests to mangroves and savannah. Over the last two decades, our understanding of this group of primates has increased dramatically. This volume presents a comprehensive overview of the current research on colobine populations, including the range of biological, ecological, behavioural and societal traits they exhibit. It highlights areas where our knowledge is still lacking, and outlines the current conservation status of colobine populations, exploring the threats to their survival. Bringing together international experts, this volume will aid future conservation efforts and encourage further empirical studies. It will be of interest to researchers and graduate students in primatology, biological anthropology and conservation science. Additional online resources can be found at www.cambridge.org/colobines.
Introduction:
Colobine monkeys are specialized folivores that use foregut fermentation to digest leaves. The slow process of fermentation forces them to spend a lot of time resting and to minimize their energy expenditure to subsist on a lower-quality diet.
Methods:
We recorded the diet and activity budget of Colobus angolensis ruwenzorii, which form a three-tiered multi-level society, at Lake Nabugabo, Uganda, over 12 months using scan sampling on adults and subadults, to determine whether they utilize the energy minimization strategy typical of colobines.
Results:
We found that the annual diet was primarily comprised of high-quality food resources (young leaves 65% and fruit 31%), and fruits were the only plant part the monkeysselected when available. Both the fruits and young leaves of some species were preferred food items in some months, and mature leaf consumption correlated negatively with preferred food availability. Mature leaves appear to be a fallback food for this population but are rarely relied upon (3%). The C. a. ruwenzoriiat Nabugabo spent less time resting (40%) and more time moving (25%) than is typical for other species of black-and-white colobus.
Discussion/conclusion:
The high-quality diet of this population appears to allow them to utilize an energy maximization strategy. Their reliance on food items that tend to be clumped in space and time likely explains the frequent fission-fusion behaviour that we observe between core units. Our findings demonstrate that the foraging strategies of colobines may be more flexible than was previously thought and illustrate how food availability and distribution can impact primate social organization.
