Temperature influences the performance and effectiveness of field and laboratory strains of the ichneumonid parasitoid, Campoletis chlorideae

To understand the influence of temperature on host-parasitoid interactions as a consequence of climatic change, we studied development, survival, and fecundity of field and laboratory strains of the Helicoverpa armigera larval endoparasitoid, Campoletis chlorideae at five different temperatures under laboratory conditions. Post-embryonic development period and degree-days required for completing the life cycle by both the strains decreased by 2.5 and 1.5 folds at 27A degrees C compared to 18A degrees C. Post embryonic development period showed a negative (r = -0.99, P < 0.001) and the development rate a positive (r = 0.99, P < 0.001) association with an increase in temperature. However, no parasitoid larvae survived in H. armigera larvae reared at 12 and 35A degrees C after parasitization, suggesting that temperatures a parts per thousand yen35A degrees C as a result of global warming will be lethal for development and survival of immature stages of C. chlorideae. Adult longevity was negatively associated (r = -0.91 to -0.96, P < 0.001) with temperatures between 12 and 35A degrees C. The parasitoid adults stored at 12A degrees C survived for longer period and exhibited higher fecundity than those kept at 27A degrees C, but the efficiency of parasitism and adult emergence were quite low. Sex ratio of the progeny at 12A degrees C was highly male-biased than the insects kept at 27A degrees C. Laboratory strain of the parasitoid exhibited better survival, and the adults lived longer than the field strain at 18A degrees C than at 27A degrees C. Therefore, C. chlorideae adults stored at 18A degrees C could be used for parasitism, while the immature stages should be reared at 27A degrees C for mass production of the parasitoid for biological control of H. armigera.