Polyrhachis loweryi (Formicinae): A guest ant parasitizing Rhytidoponera sp (Ponerinae) in Queensland, Australia

摘要

At the type locality near Miles in Queensland, Australia a queenright colony of Polyrhachis loweryi was found (I dealate queen, 91 workers, males and brood) within a colony of Rhytidoponera sp. (near aciculata), whereas other colonies of this Rhytidoponera species contained only a few workers of P loweryi. For experiments and behavioural observations P loweryi and its hosts were kept in the laboratory for some time. The queenright P loweryi colony constructed closed nests out of soil and plant fibres, within the host nest, and only containing Polyrhachis specimens. P loweryi workers in part, remained amid the assembly of Rhytidoponera, from whom they obtained carbohydrate and protein food. In addition, Polyrhachis workers regularly left the host nest. They were able to collect liquid carbohydrate food and to distribute it among conspecific nest mates via trophallaxis. The care of the P loweryi brood was fully done by P loweryi itself. However, Rhytidoponera workers were observed carrying P loweryi brood in addition to their own brood. In artificially induced nest relocations, P loweryi was able to move to a new nest independently from its host ants, displaying the typical invitation behaviour, trail laying behaviour, and leader independent trail communication found in other members of the genus. Rhytidoponera sp., which in addition to inconspicuous trail marking, performs nest relocation via social carrying, rarely but regularly also carried P loweryi to the new nest. Whereas Rhytidoponera sp. workers were carried in the typical ponerine posture, P loweryi workers were carried by them in the formicine posture. We conclude that P loweryi is best described as a guest ant of Rhytidoponera sp.. The species seems to be less well integrated into the societies of its Rhytidoponera sp. host than the closely related P. lama, a social parasite of Diacamma sp. in Java.