The evolution of eusociality.

Abstract

Eusociality is characterised by overlapping adult generations, cooperative brood care, and more or less nonreproductive workers or helpers. The most extreme cases of eusocially are species with highly specialised, permanently sterile castes of workers and soldiers. This review begins with an evaluation of the various hypotheses proposed to explain the evolution of eusociality in Hymenoptera and Isoptera. A comparative analysis of preconditions that are important for the evolution of insect eusociality follows. Finally, the occurrence of these preconditions is surveyed among vertebrates as a test of their generality. The crucial preconditions are shown to be similar in eusocial insects and eusocial-like vertebrates, eg naked mole-rat Heterocephalus glaber. No single trait can explain the evolution of eusociality: 2 conditions crucial for the evolution of eusociality are parental care (including the defence and feeding of offspring in a nest or other protected cavity), and low success of young adults or solitary pairs that attempt to reproduce.-from Author