Family PASSALIDAE

<I>Mastachilus quaestionis</I> (Kuwert, 1891)

Mastachilus quaestionis (Kuwert, 1891)

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Family PASSALIDAE

Compiler and date details

1 December 2002 - Gerasimos Cassis & Tom A. Weir; updated by Andrew A. Calder, CSIRO Entomology, Canberra, Australia

Introduction

The Passalidae are a cosmopolitan family of Scarabaeoidea, comprising about 27 genera and 500 species. They occur mostly in tropical and subtropical regions (Lawrence 1982). Hincks & Dibb (1958) listed seven subfamilies, but recent work by Reyes-Castillo (1970) reduced this to two subfamilies, the Aulacocyclinae and the Passalinae. The classification followed in this catalogue is that of Reyes-Castillo (1970).

Percheron (1835) and Kaup (1871) were the first to monograph the world fauna. Gravely (1914, 1918) revised the world fauna, provided the first modern treatment, discussed the classification, morphology, distribution, and provided new synonymies and checklists. Masters (1886) catalogued the Australian fauna, Kuwert (1891, 1898) described 18 species for Australia and Dibb (1938) reviewed the Australian fauna although he added no new species. Hincks & Dibb (1935) catalogued the world fauna and provided a supplement in 1958.

The Australian fauna comprises nine genera and 35 species; the largest number of species are assigned to Aulacocyclus Kaup, and the rest of the fauna to the Passalinae. Other large genera include Mastachilus Kaup and Pharochilus Kaup, and most of the Australian species are found in the north and the east of the continent.

BIOLOGY
This group has specialised biology and exhibits sub-social behaviour. Passalids tend to form colonies in rotten logs and the adults protect the young. The larvae feed on wood pulp prepared by adults and there is communication between larvae and adults by stridulation (Matthews 1984). In the adults, stridulation is achieved by friction between the wings and upper surface of the abdomen. The larvae produce a high pitched sound by scraping the reduced hind leg over a file on the midcoxa (Lawrence & Britton 1991).

Diagnosis

The adults of this family are usually black, large in size (20–60 mm) and somewhat flattened, with the head prognathous and sometimes armed with a short horn. The antennae are characteristically curved and there is a narrow pedicel between the prothorax and the elytra. The scutellum is not visible and the elytral striae are conspicuous (Lawrence & Britton 1991). The larvae are distinguished by the mandibles without a ventral process, the antennae are two segmented, and the body shape is less curved than other scarabaeoid larvae. The hind legs are greatly reduced and unsegmented (Ritcher 1966).