The importance of individual-to-society feedbacks in animal ecology and evolution

Abstract

1.The social decisions that individuals make, in terms of where to move, who to interact with and how frequently, scale up to generate social structure. Such structure has profound consequences: individuals each have a unique social environment, social interactions can amplify or dampen individual differences at the population level, and population-level ecological and evolutionary processes can be governed by higher-level ‘emergent properties’ of animal societies.2.Here we review how explicitly accounting for social structure in animal populations has generated new hypotheses and has revised existing predictions in ecology and evolution. That is, we synthesize the insights gained by applying ‘network-thinking’ rather than the utility of applying social network analysis as a methodological tool. 3.We start with what has been learned about the generative mechanisms that underpin social structure. We then outline the major implications that social structure has been found to have on population processes, on how selection operates and organisms can evolve, and on co-evolutionary dynamics between social structure and population processes. Finally, we highlight areas for which there is clear evidence that accounting for social structure will refine current thinking, but where examples remain scarce.4.Applying ‘network thinking’ in biology presents not only new challenges, but also many opportunities to advance different areas of research. Addressing the question of how social structure changes the biological relationships linking individuals to populations, and populations to processes, is revealing commonalities across scientific disciplines. In doing so, animal social networks can bridge otherwise disparate research topics and, in the future, we hope will allow for more unified theories in biology.

Detecting social (in)stability in primates from their temporal co-presence network

“…Alberts (2019)) and social network analysis provides powerful tools to describe social interactions and analyse their evolution through time (Hinde, 1976). In fact, social network analysis has transformed research in ecology and evolution (for a review see Cantor et al (2019)). Here, we have analysed the temporal (in)stability of a social group of baboons using an automatically collected high-resolution longterm dataset.…”

Wild songbirds exhibit consistent individual differences in inter-specific social behaviour

“…Our results demonstrate that social phenotypes translate into the heterospecific social environment, with individuals showing marked inter-individual variation in overall gregariousness, and connectedness to heterospecifics in multi-species networks. Given the growing evidence for the effects of individuals’ social environment on modulating evolutionary and ecological processes (Cantor et al 2019), the importance of decisions about the heterospecific social associations could be widely under-appreciated.…”

“…For example, both grouping and use of heterospecific social information have been shown to provide anti-predator benefits (Magrath et al 2015; Meise et al 2018; Goodale et al 2019) and foraging benefits (Dolby & Grubb 1998; Farine et al 2015) to members of mixed-species groups. In turn, interactions with heterospecifics could influence the positions of individuals within their social networks, and thereby contribute to ecological and evolutionary processes arising via the social environment (see Cantor et al 2019 for a review).…”

“…Such a bottom-up approach accounts for the effect of inter-individual differences in traits and has long been applied to study sociality in single-species groups, thus providing a theoretical and analytical basis for analysing heterospecific sociality. Social Network Analysis (SNA) has become an important method for quantifying individuals’ social decisions (such as partner choice), interaction pattern among individuals, and the emerging social structure of groups and populations (Cantor et al 2019). To our knowledge, only two studies have analysed dyadic interactions to explore the role of individual-level decisions in shaping heterospecific groups and both focus on within-species variation in measures of social behaviour (Farine et al 2012; Farine & Milburn 2013).…”

Network reaction norms: taking into account network position and network plasticity in response to environmental change

“…More generally, the ability to make predictions about social networks in changing environments can have direct implications for disease management, population level dynamics, as well as other ecological and evolutionary processes where social network structures have been shown to be an influential component [43]. Additionally, increases in geospatial infrastructure have made a growing amount of environmental data available, particularly from freely available satellite remote sensing datasets (e.g., Sentinel-2, Landsat, Modis) [44, 45], facilitating the integration of dynamic social networks with environmental measures.…”