Dispersal of the filth fly parasitoid Spalangia cameroni (Hymenoptera: Pteromalidae) in a swine facility using fluorescent dust marking and sentinel pupal bags

Fluorescent dust marking and sentinel pupal bags were used in 1998 and 1999 to examine dispersal, spatial distribution, and duration of activity of mass-released Spalangia cameroni Perkins in a swine facility. In 1998, four releases were conducted in the period May-November and in 1999 a final release was completed in August. Males were observed in large numbers on window sites shortly after releases, whereas females seemed to remain in the environment. However, in one trial, and probably due to high air temperatures in the facility, a similar flight propensity toward the window sites was noted for the females. The distribution of parasitoids was clearly aggregated within a perimeter of 3 m from the release point. The duration of activity of marked S. cameroni, measured as the number of attacked sentinel pupal bags and parasitism, declined to a low level within 2 wk from the time of release. The results are discussed in relation to release strategies of S. cameroni in control of nuisance flies.