Population Maintenance of Lucilia-Cuprina (Wiedemann) in the Arid Zone

Abstract

For 3 years numbers and species of blowflies breeding in carcasses and on live merino sheep were studied at the University of New South Wales Arid Zone Research Station at Fowlers Gap, to determine which species initiated blowfly strike on sheep and how Lucilia cuprina (Wiedemann) maintained its population throughout the year; particularly whether it could complete its life cycle on carcasses. Larvae taken from struck sheep showed L. cuprina to be the dominant species in >87% of strikes. Native calliphorids, Calliphora nociva Hardy, Calliphora augur (Fabr.), and Calliphora stygia (Fabr.) were present in about 7% of strikes sampled, usually in association with L. cuprina. In a regularly inspected small mob (c. 70) of sheep, incidence of covert strike was higher than incidence of overt strike, supporting the view that a grazier's estimate of flystrike in the flock would almost always be an underestimate. On carcasses, the secondary strike native blowfly, Chrysomys rufijacies (Macquart), was produced in very large numbers. Some native primary strike Calliphora spp. were produced from some carcasses in the colder months, but no L. cuprina was produced from either small or large carcasses (sheep, kangaroos, rabbits) at any time. However, larvae of L. cuprina were recovered from live sheep at all times of the year, indicating that L. cuprina is an obligate parasite of live sheep in the arid zone.