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Sex-biased parasitism of adult spring beetles, Heteronyx dimidiata and Heteronyx crinitus, by Tachinidae in Eucalyptus nitens plantations in Australia

journal contribution
posted on 2023-05-17, 19:46 authored by Walker, PW, Geoff AllenGeoff Allen
Parasitism of adult Heteronyx dimidiata (Erichson) and H. crinitus Blackburn (Scarabaeidae: Melolonthinae), that attack Eucalyptus nitens plantation seedlings in southern Australia, was recorded over 3 years. An undescribed genus of Blondeliini (Tachinidae: Exoristinae) was reared from both scarab species while a Palpostoma sp. (Tachiinae) was reared from H. crinitus. Flies were observed parasitising flying beetles by intercepting them mid-air. Eggs were laid externally on the exoskeleton, mainly on the dorsum of abdominal tergites. Male H. dimidiata were parasitised significantly more (40%) than female conspecifics (13%) and male or female H. crinitus (both 13%), which was attributed to their greater flight activity searching for mates. Superparasitism was common in both species, particularly in male H. dimidiata (56% of parasitised beetles, up to 22 eggs/beetle), despite evidence that only a single tachinid could complete development in a beetle. Early stages of parasitism in H. dimidiata females did not appear to affect ovarian development nor the ability of beetles to feed on young trees. However, we infer that the tachinids had a significant impact on Heteronyx spp. populations through a reduction in adult beetle longevity and fitness.

History

Publication title

Austral Entomology

Volume

53

Pagination

104-111

ISSN

2052-174X

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Wiley-Blackwell Publishing Asia

Place of publication

Australia

Rights statement

Copyright 2013 Australian Entomological Society

Repository Status

  • Restricted

Socio-economic Objectives

Control of pests, diseases and exotic species in terrestrial environments

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