Parasitization of Larvae of Paropsis Atomaria Ol. (Coleoptera: Chrysomelidae) in the Australian Capital Territory.

Abstract

Parasites of the larvae of the eucalypt-defoliating chrysomelid Paropsis atomaria Ol. in the Australian Capital Territory, Australia, in 1975-77 included the hymenopteran primary parasite Eadya paropsidis Huddleston & Short, the hyperparasites Perilampus tasmanicus Cam. and Mesochorus sp., and the tachinids Anagonia anguliventris (Mall.) (Froggattimyia anguliventris), F. tillyardi Mall. and Paropsivora sp. For the December-January 1st-generation larvae of Paropsis atomaria in 1976-77, E. paropsidis achieved an average 49% parasitism, and the tachinids 19%; the two kinds of parasites occurred together in 18% of parasitised larvae. Planidia of Perilampus tasmanicus attacked an average of 68% of the tachinid larvae and 70% of the larvae of E. paropsidis. Mesochorus occurred only in tachinid larvae, with a mean parasitism of 35% over the season, but it was not found after early January; multiparasitism with P. tasmanicus was found in 24% of parasitised tachinids. The number of progeny of the primary parasites deposited in one chrysomelid larva rarely exceeded 5 for tachinids and 6 for E. paropsidis. This occurred whether the parasites were intra- or interspecifically competing. The exceptionally high reproductive capacity of P. tasmanicus was related to poor survival: up to 50 planidia were found inside a single chrysomelid larva, in a phoretic relationship awaiting primary parasite larvae.