Offspring social network structure predicts fitness in families

Abstract

Social structures such as families emerge as outcomes of behavioural interactions among individuals, and can evolve over time if families with particular types of social structures tend to leave more individuals in subsequent generations. The social behaviour of interacting individuals is typically analysed as a series of multiple dyadic (pair-wise) interactions, rather than a network of interactions among multiple individuals. However, in species where parents feed dependant young, interactions within families nearly always involve more than two individuals simultaneously. Such social networks of interactions at least partly reflect conflicts of interest over the provision of costly parental investment. Consequently, variation in family network structure reflects variation in how conflicts of interest are resolved among family members. Despite its importance in understanding the evolution of emergent properties of social organization such as family life and cooperation, nothing is currently known about how selection acts on the structure of social networks. Here, we show that the social network structure of broods of begging nestling great tits Parus major predicts fitness in families. Although selection at the level of the individual favours large nestlings, selection at the level of the kin-group primarily favours families that resolve conflicts most effectively.Keywords: social networks; sexual conflict; parent-offspring conflict; begging; social evolution 1. INTRODUCTION Social networks analyses have advanced our understanding of the evolution of animal societies [1,2], cooperation [3][4][5], the transmission of disease [6] and human social [7] and socio-economic [8] systems. Taking a networks approach to the study of social behaviour shifts emphasis away from variation in behaviour among individuals per se to how interactions among individuals shape variation [9]. This more realistically reflects the behaviour of individuals as being both the cause and the effect of their social environment [10,11]. However, all previous research has focused on the importance of social position within a network on the fitness prospects of interacting individuals [12,13] rather than the structure of the network of interactions themselves. As a result, very little is known about the relationship between the structure of social networks and fitness in natural populations, despite the importance of such information in understanding the evolutionary and ecological significance of social networks [9,14].

Offspring dynamics affect food provisioning, growth and mortality in a brood-caring spider

“…This result suggests that offspring dynamics as described above may be a signal that prompts even unrelated foster mothers to leave more of the liquefied prey for the brood. Offspring dynamics may for example affect the conflict over food provisioning in birds [10]. In great tits (Parus major), females and males provide food differently depending on the social network structure of offspring.…”

“…Honest signalling models assume that parents actively allocate resources depending on the need of the offspring [6][7][8]. Recent studies suggest that the resolution of parent -offspring conflicts involves repeated interactions among all group members [9,10]. Royle et al [11] point out that determining control mechanisms is complex, and that offspring and female control represent the two ends of a 'power continuum'.…”

Developmental stress and social phenotypes: integrating neuroendocrine, behavioural and evolutionary perspectives

“…This work did not attempt to replicate the types of social interaction tests commonly used in the literature, providing a single individual to interact with, instead it used a more ecologically relevant tool to determine how well an individual copes in a group. Recently there has been great interest in the use of social networks and several studies have now suggested that central positions in networks can indeed have positive fitness benefits in a range of species (1,2,(116)(117)(118)(119). Indeed work in birds has also suggested that network centrality is related to specific behavioural syndromes or individual personalities (117) and such syndromes have been linked to HPA axis activity, and developmental conditions (120)(121)(122)(123)(124).…”

“…The ability to effectively interact with conspecifics is a vital skill, which we have only just begun to explore in terms of its impact on fitness (1,2). In humans, this ability is also highly valued and disorders known to reduce our ability *Author for correspondence (Karen.spencer@st-andrews.ac.uk).…”

Social dynamics, network structure, and information diffusion in fish shoals.

“…Sih et al (2009) listed four concepts embraced by SNA that are of particular importance to behavioral ecology: (i) individuals differ in their social experiences, (ii) indirect connections can be as important as direct ones, (iii) individuals differ in the extent of their influence within the social network, and (iv) the social network structure in one context can carry over to influence the network structure in other contexts. These four concepts offer a useful framework through which to appreciate the contributions SNA has made to our understanding of various topics in behavioral ecology, including: dominance hierarchies (Shizuka & McDonald, 2012;Dey et al, 2013), sexual selection (Oh & Badyaev, 2010), disease ecology (Cross et al, 2004;Godfrey et al, 2009;VanderWaal, Atwill, et al, 2014), and the influence of social structure on fitness (Royle et al, 2012;Wey & Blumstein, 2012). Here, we have chosen to focus on SNA as it relates to: (i) social learning and information diffusion, (ii) collective movement and decision-making, (iii) animal personalities, and (iv) cooperation.…”