Environmental factors affecting the behavior of Coenosia attenuata Stein, a predator of Trialeurodes vaporariorum (Westwood) in tomato greenhouses

Adults of the predatory fly Coenosia attenuata Stein (Diptera: Muscidae) catch their prey while inflight. I investigated this activity over two seasons in a tomato greenhouse naturally infested with Trialeurodesvaporariorum (Westwood) (Hemiptera: Aleyrodidae). The flight of C. attenuata individu-als was affected by environmental factors and was increased in response to increases in temperature,the number of prey flights, and conspecific density. Predator and prey flights were distributedthroughout the day, but there was a regular daily trend, each with two partially overlapping activitypeaks. The possibility of predation was limited by differences in daily flight-activity times. Predatoryflights comprised a small percentage (ca. 6%) of the total flights, with a predation success rate of ca.61%. Overall, the predatory activity of C. attenuata depended on the selection of hunting sites withgood visibility to ensure a clear view before take-off and allow the capture of prey in flight. Similarnumbers of overall flights weremade by both sexes, but C. attenuata females performedmore preda-tion flights and territorial defense activities than males. The ecological role of C. attenuata and itslimited adaptability to greenhouses is discussed in light of its possible use in biological control ofwhiteflies.