Social Organization in reactivated nests of three species ofXylocopa (Hymenoptera, Anthophoridae) in southeastern Brasil

Abstract

We have investigated the occurrence of cohabitation of several females in the same nest ofXylocopa suspecta, X. frontalis andX. grisescens which are the most common species in the region of Ribeirao Preto, S.P., Brazil. The study of social behaviour of these species involved, as a general procedure, the identification of each associated female in relation to its foraging and reproductive activity. It was observed that in each species the association of females started at the final phase of the biological cycle, when the reactivation of the nests began. Initially the association was observed to occur among mother and daughters. Subsequently only daughters remained in the nest and in the first phase of this association only one female (generally the eldest), was able to realize oviposition. Next, two ore more females were in the same condition, provisioning and ovipositing in only one cell. In the third phase the females had all the same condition, each one of them provisioning and ovipositing in their own cells. So, in the first and second phases the social behaviour corresponds to the semisocial and quasisocial levels, respectively. Nevertheless, this behaviour was transitory and the final pattern attained was communal.