Development of microsporidia-infected Muscidifurax raptor (Hymenoptera: Pteromalidae) at different temperatures

Muscididfurax raptor, a pupal parasitoid of house flies and other filth flies, is commonly infected with the microsporidium Nosema muscidifuracis. To determine the effects of infection on developmental time, uninfected and infected adult M. raptor were allowed to parasitize pupae of the house fly (Musca domestica) for 24 h. Exposed pupae of the two groups (infected and uninfected) were held at 15, 20, 25, 30, 32, and 34 °C with 75–80% relative humidity. Development of infected M. raptor was significantly longer at all temperatures than that of uninfected parasitoids, resulting in approximately 7% extensions of developmental times. Uninfected females completed development in 14.6, 19.6, and 30.4 days at 30, 25, and 20 °C, respectively, compared with 15.8, 20.7, and 32.3 days for infected females at these temperatures. The differences in developmental times provided narrow windows for isolating large proportions of uninfected M. raptor females for disease management programs. This window was greatest at 20 °C; 61% of the uninfected females emerged by day 30, at which time only 10% of the infected females had emerged.