Polyrhachis loweryi

This species parasitize Rhytidoponera colonies and can live within the nests of their host species.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Biology
Maschwitz et al. (2003) - At the type locality near Miles in Queensland, Australia a queenright colony of Polyrhachis loweryi was found (1 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. In both Polyrhachis species workers from queenright colonies perhaps emigrate with a few eggs or larvae in order to rear them in neighbouring host nests. The adaptive and predispositional reasons for the phyletic development of this parasitic relation remain unclear.

Kohout (2010) - A successful visit to the vicinity of Miles yielded numerous nests of Rhytidoponera spp. (aciculata- and convexa-groups). Following examination of ten nests of the aciculata-group sp. and five nests of the convexa-group sp., six colonies of P. loweryi were located within the nests of the former. However, on a subsequent visit to the same locality, several worker specimens of P. loweryi were also located within a nest of a Rhytidoponera species belonging to the convexa-group.

Castes
Kohout (2010) - Males and immature stages (eggs, larvae and pupae) originally deposited in the Forschungsinstitute Senckenberg, Frankfurt am Main, Germany (see Maschwitz et al., 2003) were accidently destroyed (Dorow, pers. comm.).

Nomenclature

 *  loweryi. Polyrhachis loweryi Kohout, 1990: 505 (w.) AUSTRALIA. Kohout, 2010: 200 (q.).

Queen
Kohout (2010) - Closely resembling worker and apart from sexual characters, including three ocelli, complete thoracic structure and wings, differing as follows: pronotal spines distinctly reduced to more-or-less triangular, acute teeth. Mesoscutum with anterior margin evenly rounded in dorsal view; in profile anterior face distinctly swollen, widely rounding onto flat dorsum; median line bifurcate dorsally; parapsides flat anteriorly, weakly raised posteriorly. Mesoscutellum in lateral view elevated above dorsal plane of mesosoma, relatively flat, rounding posteriorly into distinct metanotal groove. Propodeal spines short, obliquely elevated; petiolar spines similar to those in worker but distinctly shorter, their inner margins continued medially and posteriorly, forming rather blunt, V-shaped posterior margin of petiolar dorsum. Sculturation, pilosity and colour virtually identical to worker.