Eusociality and Cooperation

Abstract

The evolution of eusociality, here defined as the emergence of societies with reproductive division of labour and cooperative brood care, was first seen as a challenge to Darwin's theory of evolution by natural selection. Why should individuals permanently forgo direct reproduction to help other individuals to reproduce? Kin selection, the indirect transmission of genes through relatives, is the key process explaining the evolution of permanently nonreproductive helpers. However, in some taxa helpers delay reproduction until a breeding opportunity becomes available. Overall, eusociality evolved when ecological conditions promote stable associations of related individuals that benefit from jointly exploiting and defending common resources. High levels of cooperation and robust mechanisms of division of labour are found in many animal societies. However, conflicts among individuals are still frequent when group members that are not genetically identical compete over reproduction or resource allocation. Evolution of Reproductive Altruism and Eusociality Social life provides such advantages that it has led to a tremendous ecological success of social animals, particularly social insects. Social insects are found in almost every

The relationship between egg size and helper number in cooperative breeders: a meta-analysis across species

“…Studies providing a quantitative measure of the link between maternal investment and group size in eusocial species are rare. Moreover, we did not specifically search for these as our focus was on instances where maternal investment could vary both pre- and post-natally: in eusocial species, mothers tend not to provide any offspring care beyond egg production when helpers are present and almost all post-natal care is performed by helpers ( Keller & Chapuisat, 2010 ). We also did not include species where offspring care is shared only among reproductively active females (e.g., Grinsted, Breuker & Bilde, 2014 ), as it is difficult to determine how individual mothers differ in their investment.…”

Population genomics of eusocial insects: the costs of a vertebrate‐like effective population size

“…One of the most fascinating life‐history strategies observed in insects is eusociality, an organization characterized by caste differentiation, division of labour and cooperative brood care, which evolved many times independently in Hymenoptera (wasps, bees, ants), and once in Dictyoptera (termites, Keller & Chapuisat, ). Social insect genomics has been developing at a fast rate in recent years (Fischman et al ., ; Gadau et al ., ).…”

Peer Review #1 of "The relationship between egg size and helper number in cooperative breeders: a meta-analysis across species (v0.1)"

“…Studies providing a quantitative measure of the link between maternal investment and group size in eusocial species are rare. Moreover, we did not specifically search for these as our focus was on instances where maternal investment could vary both pre-and post-natally: in eusocial species, mothers tend not to provide any offspring care beyond egg production when helpers are present and almost all post-natal care is performed exclusively by helpers (Keller and Chapuisat, 2010). We also did not include species where offspring care is shared only among reproductively active females (e.g., Grinsted, Breuker & Bilder, 2014), as it is difficult to determine how individual mothers differ in their investment.…”