The Evolution and Ecology of Cooperative Breeding in Vertebrates

Cooperative breeding – in which some adults forgo independent breeding and remain as subordinates within a group helping to raise the offspring of others – occurs in between 3% and 10% of vertebrates. The structure of such systems varies greatly, from pairs with helpers-at-the-nest to communal breeders, andmayinclude young helpers or post-reproductive ‘grandparents’. That some individuals spend part, or all, of their lives helping others to reproduce contradicts the concept of ‘selfish’ natural selection and provides an intriguing evolutionary paradox. When and why such apparently altruistic behaviour occurs has, therefore, been the focus of much study. Although constraints and the benefits of group living, may persuade individuals to remain as subordinates, indirect ‘kin’ benefits or direct benefits (such as becoming a breeding helper) appear to favour the subsequent evolution of helping. Cooperative behaviour can have wide-ranging consequences, not only on the biology of the cooperative species, but also on those species it interacts with.