Exploring individual variation in associative learning abilities through an operant conditioning task in wild baboons

Keystone individuals - linking predator traits to community ecology

Individual behavioral plasticity enables animals to adjust to different scenarios. Yet, personality traits limit this flexibility, leading to consistent interindividual differences in behavior. These individual behavioral traits have the potential to govern community interactions, although testing this is difficult in complex natural systems. For large predators who often exert strong effects on ecosystem functioning, this behavioral diversity may be especially important and lead to individualized ecosystem roles. We present a framework for quantifying individual behavioral plasticity and personality traits of large wild predators, revealing the extent to which certain natural behaviors are governed by these latent traits. The outcomes will reveal how the innate characteristics of wildlife can scale up to affect community interactions.

Review: Herbivory and the power of phytochemical diversity on animal health

Plant secondary compounds (PSCs) were thought to be waste products of plant metabolism when first identified in the mid-1800 s. Since then, many different roles have been recognized for these chemicals. With regard to their function as defense, PSCs can negatively impact different cellular and metabolic processes in the herbivore, causing illness and reductions in feed intake. This penalty on fitness also applies to other trophic levels, like the microorganisms and parasites that infect herbivores and thus, PSCs at certain doses may function as medicines. In turn, herbivores evolved learning mechanisms to cope with the constant variability in their environment and physiological needs. Under this context, foraging can be viewed as the quest for substances in the external environment that provide homeostatic utility to the animal. For instance, herbivores increase preference for PSC-containing feeds that negatively impact infectious agents (i.e., therapeutic self-medication). Given that some classes of PSCs like polyphenols present antioxidant, antiinflammatory, immunomodulatory and prebiotic properties, chronic and sustained consumption of these chemicals results in robust animals that are tolerant to disease (i.e., prophylactic self-medication). Foraging plasticity in terms of the quality and quantity of nutrients ingested in the absence and during sickness may also influence immunocompetence, resistance and resilience to infection, and thus can be interpreted as another form of medication. Finally, self-medicative behaviors can be transmitted through social learning. We suggest that foraging studies will benefit from exploring self-medicative behaviors in chemically diverse plant communities, in particular when considering the vast diversity of PSC structures (more than 200 000) observed in nature. We then lay out a framework for enhancing the medicinal effects of PSCs on grazing herbivores. We propose landscape interventions through the establishment of resource patches or "islands" with a diversity of PSC-containing forages (e.g., legumes, herbs, shrubs) in monotonous rangelands or pasturelands, viewed as a "sea" of low-diversity vegetation devoid of functional biochemicals. Strategies aimed at enhancing the diversity of plant communities lead to heterogeneity in chemical, structural and functional landscape traits that offer options to foragers, and thus allow for balanced diets that maintain and restore health. Beyond animal health, such heterogeneity promotes a broad array of ecosystem services that significantly improve landscape resilience to environmental disturbances.

Intolerant baboons avoid observer proximity, creating biased inter-individual association patterns

Social network analysis is an increasingly popular tool for behavioural ecologists exploring the social organisation of animal populations. Such analyses require data on inter-individual association patterns, which in wild populations are often collected using direct observations of habituated animals. This assumes observers have no influence on animal behaviour; however, our previous work showed that individuals in a habituated group of chacma baboons (Papio ursinus griseipes) displayed consistent and individually distinct responses to observer approaches. We explored the implications of our previous findings by measuring the inter-individual association patterns of the same group of chacma baboons at different observer distances. We found a strong positive association between individual tolerance levels (towards observers) and how often an animal appeared as a neighbour to focal animals when observers were nearer, and a neutral relationship between the same variables when the observer was further away. Additionally, association matrices constructed from different observation distances were not comparable within any proximity buffer, and neither were the individual network metrics generated from these matrices. This appears to be the first empirical evidence that observer presence and behaviour can influence the association patterns of habituated animals and thus have potentially significant impacts on measured social networks.