COLONY STRUCTURE OF A BAMBOO-DWELLING TETRAPONERA SP (HYMENOPTERA, FORMICIDAE, PSEUDOMYRMECINAE) FROM MALAYSIA

The colony structure of the bamboo-inhabiting SE-Asian pseudomyrmecine ant Tetraponera sp. PSW-80 near attenuata F. Smith was investigated at the Ulu Gombak Field Studies Centre, Selangor, West-Malaysia. Based on the dissection of 54 stem internodes from 12 different culms of the large bamboo Gigantochloa scortechinii Gamble and on the mapping of three colonies, the following demographic characteristics emerge. The colonies are monogynous but highly polydomous (at least up to 36 internodes and up to 9 stems occupied) and very populous for a pseudomyrmecine not involved in an ant-plant mutualism. One completely censused colony had 6953 adult workers and 2079 alates (adults plus pupae). The single queen suppresses gyne development in her own ''nest'' and. to a lesser extent, in other ''nests'' within the same stem. The overall numerical sex ratio was 0.96:1 (females:males), the investment sex ratio, 2.93:1, i.e., almost exactly the 3:1 ratio expected for a monogynous outbred hymenopteran in which the colony queen also produces all the male offspring. Brood is distributed to all other nest chambers from the queenright chamber. The symbiotic pseudococcids (Kermicus wroughtoni Newstead) are present in all inhabited internodes, with small early instar individuals prevailing numerically by far over the larger stages. The richt well secluded honeydew supply within the internode and the efficient architectural protection provided by the internode wall (access usually only through a 2 x 3 mm-hole) allow T sp. PSW-80 to reach an unusually large colony size without being an aggressive and protective plant mutualist like other members of its subfamily with similar demographic features.