Nest architecture, worker reproduction, and polygyny in the ponerine ant Harpegnathos venator

Abstract

The Indian jumping ant Harpegnathos saltator is one of the most well-studied ant species; however, little is known about the biology and behavior of sister species in the genus. To understand the universality of the phenomena revealed in H. saltator, biological studies of closely related species are important. We investigated the nest architecture and colony reproductive structure of Harpegnathos venator at two sites in northern Thailand. Nests had chimney-like entrances with a funnel diameter of about 3 cm and consisted of two or three chambers, the floors of which were flat and smooth. The floors and walls inside the chambers were decorated with several small fragments of cocoons, which has been referred to as “wall-papering”. Most colonies included one or more mated dealate queens that laid eggs, whereas only a few mated workers reproduced in the queenright colonies. In our sampling, virgin dealate queens were found in several colonies, but there were very few queenless colonies that reproduced by mated workers. Additional colonies collected from three other sites in Thailand also had dealate queens. The H. venator colonies reproduced mainly by mated queens, although many mated workers were present. The nest architecture of H. venator was similar to that of H. saltator, but the colony reproductive structure was different: queen colonies of H. saltator are always monogynous, and queenless colonies that reproduce by gamergates are frequently found. Furthermore, virgin dealate queens are never found in H. saltator. Factors affecting these differences between the two congeneric species are discussed.