Lepidiota Kirby 1828

Sub family: Melolonthinae / Tribe: Melolonthini / Genus: Lepidiota

Large cylindrical beetles, body length 15-38mm. Body colouration black, brown, dark brown or reddish brown. Body surfaces commonly covered in white or yellowish scales, sometimes sparsely, sometimes wholly contained within punctations. Clypeus emarginate, commonly appearing bi-lobed. Anterior face shallow, and usually smooth and unpunctured medially. Antennae 10 segmented (rarely 9 segmented), with a 3-segmented lamellate club (though 2 Australian species with 5 lamellae). Antennal club not elongated, usually shorter than the length of first 7 segments. Metasternal process absent. Tarsal claws with a median tooth.

There are over a 150 known species of Lepidiota, with 55 present in Australia. Outside of Britton's 1978 revision of the Australian fauna, there have been no publications revising the group as a whole. Miller and Allsop (2000) provide a key for Australian species in sugarcane.

In Australia it has been placed within the tribe Melolonthini which share the following features:

Abdominal sternites at least partially fused, sutural lines present between sternites, even when fused. Meso and metatibia with 2 spurs placed below the tarsal articulation. Tarsal claws usually equal and toothed. Antennae 9 or 10 segmented (rarely 8), Antennal lamellae 3-7 segmented. Labrum located below clypeus, distinct. 5th Abdominal sternite and propygidium separated by a suture. Protibia with apical spurs.

An updated key to the Australian genera of Melolonthini is provided by Weir et.al. (2019).

Exotic Lepidiota can be most easily confused with Leucopholis, which are similar sized, and scale covered.

All species of Leucopholis possess scales over the entirety of the body, a mesometasternal process and a flattened prosternal process. The presence or absence of body scales is variable for Lepidiota, and the mesometasternal process, while absent in all Australian Lepidiota, appears to occasionally be present in species from South East Asia. Calcetas and Aldorada (2019) note the prosternal process for Leucopholis as flattened and glabrous, while in Lepidiota it is without a flattened area and setose, though this is not always a reliable feature. The labrum of Leucopholis is also noted as generally narrower than Lepidiota. Further work needs to be undertaken to provide clear separations between the genera.  

Diagnostic notes and image sets for 15 species of Australian Lepidiota are available on PaDIL: http://www.padil.gov.au/pests-and-diseases/search?queryText1=Lepidiota&queryType1=all

Lepidiota stigma is an exotic pest species absent from Australia and recorded from many Asian countries. The name, however, appears to be widely used historically without proper specimen examination and comparison, so care should be taken when viewing online records. Unlike Australian Lepidiota, it possesses a large, pointed mesometasternal process.

Larvae of Lepidiota are root feeders, with some species capable of significant economic damage to a number of crops including sugarcane, maize, coffee and cassava. Others species such as L. laevis are known to damage pastures. Larvae development can take 1-2 years. Adult beetles are active at night and can be attracted to lights.

Lepidiota are found across the Oriental region, from India, China, Thailand, Malaysia, the Phillipines, and southwards into Papua New Guinea and northern Australia.

Most Australian species are quite restricted in their known localities. The main exception is L. squamulata's broad distribution across the northern half of Australia.

Lepidiota carolinensis species page (Hawaiian Scarab Website): http://idtools.org/id/beetles/scarab/factsheet.php?name=15230

Britton, E.B. 1978. A revision of the Australian chafers (Coleoptera: Scarabaeidae: Melolonthinae) Vol. 2. Tribe Melolonthini. Australian Journal of Zoology, Supplementary Series 60, 1–150.

Kalshoven, L., Edmund, G., van der Laan, P.A. 1981. Pests of crops in Indonesia. Jakarta: Ichtiar Baru. 701pp.

Miller, L. & Allsopp, P. 2000. Identification of Australian Canegrubs (Coleoptera: Scarabaeidae: Melolonthini). Invertebrate Taxonomy Vol 14: 377-409.

Weir T.A., Lawrence J.F., Lemann C., Gunter N.L. 2019. 31. Scarabaeidae: Melolonthinae Leach, 1819. In: Australian Beetles. Volume 2. Archostemata, Myxophaga, Adephaga, Polyphaga (part) (eds A Ślipiński & JF Lawrence) pp. 516–530. CSIRO, Clayton, Australia.