The effect of laboratory colonization on parasitization rate and fitness of Spalangia cameroni (Hymenoptera: Pteromalidae), a pupal parasitoid of filth flies on livestock facilities

Filth flies, such as stable flies (Stomoxys calcitrans) and house flies (Musca domestica), are frequent pests in livestock operations.  These flies are mechanical vectors of disease and can cause pain and loss of physical condition to livestock. Conventional control of filth flies has relied on high amounts of various insecticides, however, filth fly pests are becoming increasingly resistant to many registered insecticides and overuse may result in environmental contamination. Biological control using pupal parasitoids (Hymenoptera:Pteromalidae) is an alternative to chemical insecticides and a sustainable option for filth fly control in livestock operations.  Though Pteromalid parasitoid sales are increasing for commercial insectaries, augmentative releases have been evaluated on cattle and poultry operations with inconsistent results.  Failures in parasitoid induced fly control may be due to deterioration in quality of parasitoids reared under laboratory conditions versus wild-type populations. Declines of control efficacy can be attributed to deterioration in laboratory reared insects. Physiological, behavioral and life history characteristics may be modified with the propagation of small cultures of insects in the lab.  The mass rearing of Pteromalids in the laboratory may reduce their fecundity and host searching ability when released in the field, not resulting in the desired pest control. The purpose of this project was to understand how prolonged rearing of Spalangia cameroni, a common parasitoid in Florida, influences fitness. Using established colonies of S. cameroni of various ages, host parasitism, fecundity and survival were measured.