An Early Screening Tool for Exotic Scarab Pests to Australia
Scarabaeidae is the largest family within the monophyletic Scarabaeoidea superfamily. It encompasses over 1,600 genera and exceeds 27,000 species worldwide, with numerous species still awaiting description.
The larvae of Scarab beetles feed on decomposing plant material, dung or live plant parts. While most of the adult beetles are herbivorous, sap or nectar/pollen feeders, some do not feed at all. Within the phytophagous Scarabs (belonging to the subfamilies Cetoniinae, Dynastinae, Melolonthinae and Rutelinae), there are very significant agricultural and forestry pest species occasionally skeletonising trees and completely destroying crops.
The Australian native fauna is speciose, with a high level of endemism and many undescribed species. Apart from a small number of pest species, the biology of most native Australian Scarabs remains unknown.
Of the Scarab fauna within Australia, there are intentionally introduced species, particularly dung beetles, alongside unintentional incursions. There is a growing number of exotic Scarabs recognised as agricultural pests, damaging plants through defoliation by adults or from larvae causing significant economic loss through feeding on the roots of various plants.
Exotic Scarab pest species also have the potential to significantly impact on Australian native flora. Some of the more unusual pests, such as biotypes of the palm-destroying coconut rhinoceros beetle, Oryctes rhinoceros, may have major impacts on native and ornamental palms, along with coconut and date production.
The expansions of global trade pathways add to the risks of further exotic introductions of Scarab beetles and highlight the importance of biosecurity. The diversity of Australian agricultural productions, encompassing tropical regions across northern Australia, Mediterranean systems and cool climate areas, mean that the incursion and establishment of a broad range of exotic Scarab species is possible.
Successful eradication and prevention of exotic Scarab incursions, therefore, requires early detection and reliable identification. The lack of comprehensive revisions, outdated or foreign language references, and limited access to physical specimens, are common impediments to rapid and accurate diagnostics. Some available references are well written and up to date, but are restricted to particular geographic areas, and are of limited use in the Australian context. High quality diagnostic images for a range of taxa are a more recent phenomenon as printing and online hosting costs diminish, and internet access speeds increase.
The Lucid Key aims to assist diagnosticians and biosecurity related scientists in the front line identification of phytophagous (plant feeding) Scarab beetles from the subfamilies Cetoniinae, Dynastinae, Melolonthinae and Rutelinae. It encompasses a range of exotic pest species, some of which are highly invasive to new regions. The key also includes a number of commonly encountered native and introduced species in Australia.
Cameron Brumley, Department of Primary Industries and Regional Development Western Australia
Pia Scanlon, Department of Primary Industries and Regional Development Western Australia
Andras Szito, Department of Primary Industries and Regional Development Western Australia
Brumley, C., Scanlon, P., Szito, A. 2020. Scarab Pests to Australia. Lucidcentral.org, Identic Pty Ltd, Queensland, Australia.