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.

Item Type:	Refereed Article
Keywords:	Blondeliini, Melolonthinae, Palpostoma, Scarabaeidae, tachinid
Research Division:	Agricultural, Veterinary and Food Sciences
Research Group:	Forestry sciences
Research Field:	Forest health and pathology
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Control of pests, diseases and exotic species in terrestrial environments
UTAS Author:	Walker, PW (Dr Paul Walker)
UTAS Author:	Allen, GR (Associate Professor Geoff Allen)
ID Code:	86666
Year Published:	2014
Web of Science® Times Cited:	2
Deposited By:	Tasmanian Institute of Agriculture
Deposited On:	2013-10-09
Last Modified:	2017-11-09
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