PREDATORY BEHAVIOR OF SCATOPHAGA-STERCORARIA UNDER LABORATORY CONDITIONS

Laboratory experiments tested the effectiveness of Scatophaga stercoraria (L.) as a predator of various insect species. Photophases, ages and gender of predators and effects of dung presence on predation rates were compared for either sex using counts of prey cadavers, behavioral observations and oviposition rates. Males consistently killed more prey than females, but longer photophases did not significantly increase daily predation rates. Nine to 10-day-old flies approaching sexual maturity achieved highest predation rates. Dung was found to affect predatory behaviour but not cumulative predation. Predatory behaviour of sexually mature males was more affected than female behaviour by the presence of dung, whereas sexually immatures flies showed no response to dung presence. Preconditioning of S. stercoraria adults using 3 prey species of different sizes did not affect the prey chosen in subsequent random choice experiments. Larger prey species such as Musca domestica (L.) or Delia antiqua (Meigen) were preferred to Drosophila sp. by both sexes of S. stercoraria. This species may be a useful predator for future integrated pest management techniques in vegetable crops or control of house flies in barns.