Abstract
Predation risk is a major ecological factor selecting for group living. It is largely ignored, however, as an evolutionary driver of social complexity and cooperative breeding, which is attributed mainly to a combination of habitat saturation and enhanced relatedness levels. Social cichlids neither suffer from habitat saturation, nor are their groups composed primarily of relatives. This demands alternative ecological explanations for the evolution of advanced social organization. To address this question, we compared the ecology of eight populations of Neolamprologus pulcher, a cichlid fish arguably representing the pinnacle of social evolution in poikilothermic vertebrates. Results show that variation in social organization and behavior of these fish is primarily explained by predation risk and related ecological factors. Remarkably, ecology affects group structure more strongly than group size, with predation inversely affecting small and large group members. High predation and shelter limitation leads to groups containing few small but many large members, which is an effect enhanced at low population densities. Apparently, enhanced safety from predators by cooperative defense and shelter construction are the primary benefits of sociality. This finding suggests that predation risk can be fundamental for the transition toward complex social organization, which is generally undervalued.
Funder
Swiss National Science Foundation
Publisher
Proceedings of the National Academy of Sciences
Reference61 articles.
1. Barbosa P Castellanos I , eds (2005) Ecology of Predator-Prey Interactions (Oxford Univ Press, Oxford)
2. Caro T (2005) Antipredator Defenses in Birds and Mammals (Univ of Chicago Press, Chicago)
3. Krause J Ruxton GD (2002) Living in Groups (Oxford Univ Press, Oxford)
4. The Evolution of Social Behavior
5. Group Size and Predation Risk: A Field Analysis of Encounter and Dilution Effects
Cited by
106 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献