The Biology of Cephalodesmius a Genus of Dung Beetles Which Synthesizes Dung from Plant Material Coleoptera Scarabaeidae Scarabaeinae

The complex and aberrant biology of the endemic, Australian dung beetle genus, Cephalodesmius, is described from a detailed study of C. armiger and supporting observations on the other 2 spp. of the genus, C. laticollis and C. quadridens. Permanently bonded pairs occupy fixed, subterranean nests in the rainforest floor during their year-long lifespan. Males forage outside the nest for leaves and other plant materials which are processed and cultured by the female into a malleable, dung-like material which is used to construct small brood balls containing larvae. During larval growth the parent beetles cooperate in progressive provisioning of the larval brood balls, a complexity unknown elsewhere in the dung beetles and probably unique in the Coleoptera. Audible stridulation is recorded for the 1st time in larval Scarabaeidae, and a new mechanism of sound production described in which the tip of the abdomen is rubbed against the underside of the head. Stridulation is interpreted as communication between larva and adult. The brood nests of Cephalodesmius are inhabited by a suite of 8 other insects and mites [Macrocheles tenuirostris, Hunteracarus womersleyi, Histiostoma sp., Caloglyphus sp., Sinella sp., Anotylus sp. nov., Oxytellus sp. and Leptocera myrmecophila] which enter into a variety of trophic and phoretic relationships with the beetles. The evolutionary significance of the behavior of Cephalodesmius is discussed.