Subfamily Rutelinae

<I>Anoplognathus boisduvalii </I>Boisduval, 1835

Anoplognathus boisduvalii Boisduval, 1835

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Subfamily Rutelinae

Compiler and date details

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

Introduction

The Rutelinae are a cosmopolitan subfamily of Scarabaeidae, comprising about 200 genera and 3,800 species. The tribal classification used in this Catalogue follows Carne (1958) and Machatschke (1972).

Burmeister (1844) gave the first comprehensive definition and subdivision of the Rutelinae. His system was used by Lacordaire (1856) in a generic treatment, and Gemminger & Harold (1869) also used this classification in the first world catalogue. Subsequent catalogues include Ohaus (1918) and Machatschke (1972, 1974). Ohaus (1934) reviewed the world Rutelini and provided keys to the subtribes and genera, redescribed genera, and listed included species. Machatschke (1957) monographed the tribe Anomalini and Machatschke (1965) reviewed the other four tribes, including the Anoplognathini.

Four of the six recognised tribes are present in Australia. The Adoretini, which is very diverse in the Oriental, Palaearctic and Afrotropical Regions, is represented in Australia by one species of Adoretus Castelnau. Similarly, the large cosmopolitan tribe Anomalini is poorly represented in Australia with only two species of Anomala Samouelle known. The Anoplognathini is present in Australia, New Guinea and the Neotropical Region. In Australia, the subtribe Anoplognathina is represented by seven genera. All are endemic except for one subspecies, Anoplognathus punctulatus insularis Ohaus, which is found in New Guinea. The two largest genera are Anoplognathus Leach, commonly known as Christmas beetles, with 36 species, and Paraschizognathus Ohaus which has 14 species. The subtribe Schizognathina comprises 13 genera, all of which are endemic to Australia.

In the Neotropical Region, the Anoplognathini includes three endemic subtribes and the fauna is approximately the same size as the Australian fauna. The Rutelini is a cosmopolitan tribe represented in Australia by two species of the basically Oriental genus Parastasia Westwood: P. montrouzieri Fairmaire and P. terraereginae Kuijten (Kuijten 1992).

The first described Australian ruteline was Melolontha aenea Fabricius, 1775. The Australian fauna comprises 23 genera and 112 species. Macleay (1864, 1871, 1873, 1887) was the first major Australian worker and described 14 new species. Blackburn (1888, 1890, 1892, 1900) described six new species and Lea (1914, 1917, 1919, 1920) described 20 new species. Ohaus (1898, 1901, 1904, 1912, 1913, 1935) described three new genera and 23 new species, and in his 1904 paper he revised the Anoplognathini.

Carne (1954, 1956, 1957, 1958, 1974, 1975, 1981, 1985) described three new genera and 29 species. He also revised the genus Anoplognathus, giving a key to the species (Carne 1957), reviewed the entire Australian fauna, listed all the known species, and provided keys to all taxa (Carne 1958). Allsopp (1988, 1989, 1990, 1992), Allsopp & Carne (1986a, 1986b) and Kuijten (1992) described a new genus and seven new species.

BIOLOGY
The biology of many species of Rutelinae is poorly known. Adults of genera such as Calloodes White, Repsimus Macleay, Anoplognathus Leach, Epichrysus White and Anoplostethus Brullé are all primarily diurnal and feed on the foliage of Eucalyptus species, Acacia species and other trees. Both sexes feed, mating takes place on the food plant and sexual dimorphism is minimal. Species of Anoplognathus often occur in numbers sufficiently large to cause severe defoliation of eucalypts and some species are regarded as pests (Carne et al. 1974). Species of Repsimus are plentiful along sandy river banks where they feed on eucalypts and Leptospermum species (Moore 1986). In contrast, Paraschizognathus species are nocturnal, exhibit marked sexual dimorphism and probably do not feed. Females of these species, which are sedentary in the soil and are rarely collected, are difficult to associate with males. The larvae generally occur in the soil, have three instars, and, at least in Anoplognathus and Repsimus, feed primarily on organic matter (Carne et al. 1974; Moore 1986). McQuillan (1985) described the larval stages of Anoplognathus suturalis Boisduval and Saulostomus villosus Waterhouse.

Diagnosis

Members of the Rutelinae are metallic beetles of stout build. They range in size from 7 mm for Mimadoretus flavomaculatus (Macleay) to over 30 mm for some species of Calloodes White and Anoplognathussa Leach. In the adult stage they can be distinguished from other subfamilies of Scarabaeidae by a combination of the following character states: tarsal claws unequal, and large and moveable; elytra leaving pygidium exposed and often with a membranous margin beneath; abdominal spiracles strongly diverging so that several lie on abdominal sternites and at least one pair exposed; head and pronotum without prominences. The larvae differ from other scarabaeid subfamilies by a combination of the following character states: apical antennal segment as wide as penultimate; galea and lacinia fused to form a mala; anal cleft transverse; sternum 9 without a raster of longitudinal rows of spines; mandible with ventral stridulating area; symmetrical labrum with deeply pigmented notch on right side of midline; legs large with hind coxa larger than width of clypeus; stridulatory teeth on dorsal edge of maxilla always with anteriorly directed points and head not strongly punctate (Lawrence & Britton 1991).