Impact of host suitability on some biological and behavioral traits of the tachinid Compsilura concinnata

To better understand the biology of Compsilura concinnata (Meigen) as a potential biological control agent, it is necessary to determine suitability for potential hosts. In this study, laboratory tests were performed to investigate the acceptance and suitability of two key insect pests, e.g. Pieris rapae (L.) and Spodoptera litura (Fabricius) as host species for C. concinnata . In the first experiment, no significant difference was found for larval and pupal development duration, male and female puparium weight, female longevity period, sex ratio, adult yield, and fecundity of C. concinnata between P. rapae and S. litura. However, the parasitism rate and the host larval mortality were significantly higher for S. litura (58.37% and 65.82%, respectively) than for P. rapae (54.21% and 62.26%, respectively), but the values were very close between the two pests. In the second experiment, it was found that the ability of the parasitoid to locate between the hosts was insignificant. Nevertheless, the mean time to deposit two C. concinnata larvae was significantly longer for S. litura than P. rapae (third experiment). Overall, this finding indicates that C. concinnata could effectively contribute to lowering the population size of P. rapae and S. litura. Further studies must be done to apply C. concinnata successfully against these two host species in field and semi-field conditions.