Intra-Specific Mutualism and Kin-Association of Cofoundresses In Allodapine Bees (Hymenoptera Anthophoridae)

Although allodapines are thought to have achieved eusociality via the familial route, Exoneura bicolor Smith (Hymenoptera Anthophoridae) exhibits both high frequencies of nest cofounding and high levels of relatedness between cofoundresses. Both these traits may facilitate the evolution of non-reproductive castes without the need for high worker-brood relatedness hypothesized by the 3/4 relatedness hypothesis. I argue that kin association is favoured in purely mutualistic partnerships when not all individuals in a population are guaranteed partners. Furthermore, the allodapine trait of communal progressive rearing may lead to selection against partnerships with non-kin because of the opportunity for nestmate parasitism. Pronounced semisociality among brood produced in cofounded nests of E. bicolor provides strong evidence that mutualistic associations can facilitate the evolution of reproductive division of labour.