Immature stages of the bee fly Ligyra satyrus (F.) (Diptera: Bombyliidae): A hyperparasitoid of canegrubs (Coleoptera: Scarabaeidae)

ABSTRACT

We describe the third- and fourth-instar larva, pupa and biology of the hyperparasitoid bee fly Ligyra satyrus (Fabricius). The larval and pupal morphology of the bee fly is typical for members of the subfamily Anthracinae. The bee fly larvae are found inside cocoons of the scoliid Campsomeris tasmaniensis Saussure, an external parasite of canegrubs (Coleoptera: Scarabaeidae) in sugarcane fields at Ayr and Bundaberg, Queensland. Ligyra satyrus has been recorded attacking only C. tasmaniensis. Ligyra and its relatives are all parasites of predatory and parasitic, ground-nesting aculeate Hymenoptera such as Sphecidae, Pompilidae, Tiphiidae and Scoliidae. Larval morphology of the hyperparasite is similar to other ectoparasitic Bombyliidae and pupal morphology is compared to that of species in the same and related subfamilies. Rates of hyperparasitism at Gordonvale reported in the early 1900s are relatively high, but our results show that currently they are very low at Ayr and Bundaberg. These results suggest that the impact of the bee fly on natural control of the canegrubs by scoliids varies considerably.