Morphology and phenology of the primitive ponerine army ant Onychomyrmex hedleyi (Hymenoptera: Formicidae: Ponerinae) in a highland rainforest of Australia

Abstract

Phenology and morphology of the ponerine nomadic ant Onychomyrmex hedleyi were studied in Raveshoe, North Queensland, Australia. The genus belongs to the primitive ponerine ant tribe Amblyoponini and has been considered to be important for evolutionary studies of army ant behaviour. Queens were wingless but significantly different from workers in head width-length allometry, exhibiting dichthadiiform conditions. Colonies were mostly monogynous and occasionally orphan, with the mean colony size 850.1 ± SD 340.9, which was among the smallest in army ants but the largest in amblyoponine ants. Overwintering forced the colonies to bivouac up to 12 cm deep underground and divided the brood into two groups. In the ovarioles of queens, the production of oocytes peaked in October and January, which corresponded to the oviposition seasons of the two brood groups.