Biology of the Eucalypt gall-forming fly Fergusonia flavicornis Malloch (Diptera: Fergusoninidae) and its associated hymenopterans in South Australia, with a description of a new species of Bracon (Hymenoptera: Braconidae)

Abstract

Galls initiated by the association of Fergusonina flavicornis Malloch (Insecta: Diptera: Fergusoninidae) and Fergusobia sp. (Nematoda: Sphaerulariidae) on Eucalyptus camaldulensis Dehnh. at Goolwa, South Australia were monitored during a single, late summer generation for emergence of flies and associated Hymenoptera. The morphology of the galls is described for the first time. A total of 12 hymenopteran species was reared from galls, twice the number previously recorded from Fergusonina/Fergusobia galls. There was a strong positive correlation between emergence of flies, combined totals of flies and wasps and gall size. Bracon fergusoninus sp. nov., a probable primary parasitoid of F. flavicornis larvae, is described. Notes on the biology and taxonomy of each hymenopteran species are presented along with an illustrated key to their identification.