Daily patterns of flight activity of blowflies (Calliphoridae : Diptera) in the Canberra district as indicated by trap catches

Abstract

Patterns of blowfly flight activity were studied in the Canberra district by clearing traps at 90-min intervals throughout sampling days. In hot weather there were pronounced morning and afternoon peaks in the trap catches of Calliphora stygia and C. augur, and there were morning and evening peaks in the male to female ratio. In the colder months the curves of the trap catches were unimodal. Microcalliphora varipes visited traps for a shorter period each day than the Calliphora species. Its flight activity patterns were also bimodal in the hottest months, sometimes with a pronounced evening peak. Chrysomya rufifacies, Phaenicia cuprina, and P. sericata also commenced to enter traps much later in the day than Calliphora species and the curves of the daily catches were essentially unimodal. There was wide variation in the air temperature at which first and last flies of any species were caught each day, or at which peaks and troughs occurred in catches. Temperature when activity ceased tended to be higher than when activity commenced on the same day. The possible influence of radiation intensity on flight activity is discussed.