Observations on the hunting and mating behaviours of two species of scorpion flies (Bittacidae : Mecoptera)

Abstract

This paper describes the hunting and mating behaviour of two species of Harpobittacus which are endemic to Australia. The larvae of H. australis, and probably also those of H. nigriceps, are scavengers, whereas their adults are rapacious predators. Their prey include a wide variety of soft-bodied insects and spiders. In the field only the male was observed to hunt and capture its prey with its powerful raptorial hindlegs. After taking a short meal, the male curves its abdomen to evert two intertergal vesicles between segments 6 and 7 and segments 7 and 8. These vesicles contract and expand in a slow rhythmic motion and discharge a sex pheromone which attracts the female. As soon as copulation is established the male passes the prey to the female which feeds on it as a nuptial meal while mating is in progress. Both sexes mate several times daily throughout their entire lifetimes. The hunting and mating behaviour of the two species differ only in that the nuptial meal remains in the possession of the male H. australis, the same prey being used for several mating actions with different females. In H. nigriceps, the meal is in possession of the female which discards it just prior to the termination of copulation. In this species a fresh nuptial meal is provided by the male on each mating occasion. It is suggested that similar mating behaviour may occur in other genera of Bittacidae, notably in the worldwide genus Bittacus.