Nesting biology of the stem-nesting wasp Psenulus interstitialis Cameron (Hymenoptera : Crabronidae : Pemphredoninae) on Magnetic Island, Queensland

Psenulus interstitialis constructed nests of up to 10 cells in bamboo inter nodes on Magnetic Island, Queensland. Prey represented five families of Auc henorryncha, primarily late-instar nymphs. Fully provisioned cells held 9-1 3 prey. Development required about 30 days, and the reared sex ratio was ma le biased at 2:1. There are probably several generations a year at this lat itude. The three species of chalcidoid parasitoids reared, Leucospis giraul ti Boucek, Eupelmophotismus pulcher (Girault) and Calosota sp., all attacke d late-larval or early pupal stages. Additional mortality was caused by a s pecies of Pyemotes mite and an unidentified fungus. This is the first biolo gical information for any Australian species of Psenulus.