Biology and immature stages of Helosciomyza subalpina (Diptera: Helosciomyzidae), an ant-killing fly from New Zealand

Abstract

Biological features of adults and immature stages of Helosciomyza subalpina Tonnoir & Malloch are discussed. Information on habitat, geographical distribution, larval behaviour and feeding habits, natural enemies, and phenology are presented. The species is found in marshy areas in the South Island and on the Chatham Islands. In the laboratory, newly hatched larvae feed on a variety of freshly killed insects, and apparently lap up liquids from the integument of live ant larvae. Older fly larvae feed on decaying as well as freshly killed insects, and are overt predators of ant larvae. In the field, fly larvae and puparia have been found in association with ant nests; many puparia have also been found well away from ant nests. The egg, three larval instars, and the puparium are described. The taxonomic position of the Helosciomyzidae is discussed in the light of these new data on biology and morphology.