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Polyrhachis is an extremely interesting genus!

In recent times we have studied two species belonging to the P. viehmeyeri-group in subgenus Myrmhopla, both obligatory social parasites resp. guest ants of host species belonging to a different subfamily, the Ponerinae.

1)Maschwitz, U., W.H.O. Dorow, A. Buschinger & G. Kalytta (2000): Social parasitism involving ants of different subfamilies: Polyrhachis lama (Formicinae) an obligatory inquiline of Diacamma sp. (Ponerinae) in Java. Insectes soc. 47, 27-35.

2) Maschwitz, U., C. Go, W.H.O. Dorow, A. Buschinger, & R.H. Kohout :Polyrhachis loweryi (Formicinae) : A guest ant parasitizing Rhytidoponera sp. (Ponerinae) in Queensland, Australia. Insectes soc., in press.

In both instances we now believe that the parasitic Polyrhachis species are monogynous but polydomous, a colony always inhabiting and exploiting several neighboring host species nests. We found a dealate Polyrhachis queen only rarely, together with a small number of Polyrhachis workers, in a host nest. However, about five to seven times more host nests comprise a few parasite workers each, and a parasite brood from which parasite workers, males and gynes are reared. We have evidence that Polyrhachis lama workers with young brood from a queenright mother nest move into neighboring Diacamma nests where they rear this brood with food taken from the host workers. Absolutely surprising is the fact that both the Diacamma and the Rhytidoponera hosts exhibit practically no aggressiveness towards their "guests". Sometimes they even carry the parasites' pupae, or lead the adults e.g. to a new nest site.
There are some more reports on Polyrhachis species having been found somehow "together" with other ant species. Perhaps quite a number of Polyrhachis species have parasitic relations with unrelated host species (in contrast to the classical inquilines, temporary parasites and slavemakers which all are, according to "Emery's rule, close relatives of their respective host species groups).

A. Buschinger