Social organization in experimentally assembled colonies of Ropalidia marginata: comparison of introduced and natal wasps

Abstract

In the primitively eusocial wasp, Ropalidia marginata worker behaviour cannot be explained satisfactorily by the haplodiploidy hypothesis due to the existence of polyandry, serial polygyny and movement of wasps between nests, which reduce intra-colony genetic relatedness to levels lower than the value expected between a solitary foundress and her offspring. We introduced wasps eclosing from one set of colonies into other colonies separated by a distance of 10 km or more, to examine the possibility of kin recognition and task specialization under conditions of low intracolony relatedness. Introduced wasps were readily accepted into unrelated foster colonies, where they performed most of the behaviours and tasks shown by the natal wasps. We found no evidence of kin recognition or task specialization among natal and introduced wasps. Introduced wasps sometimes became replacement queens in spite of the presence of natal wasps. Taken together with previous observations, these results lend support to the idea that factors other than genetic relatedness must play a prominent role in the evolution of worker behaviour in Ropalidia marginata.