GEOGRAPHIC-VARIATION IN HOST SELECTION BEHAVIOR AND REPRODUCTIVE SUCCESS IN THE STEMBORER PARASITOID COTESIA-FLAVIPES (HYMENOPTERA, BRACONIDAE)

Local parasitoid populations may be adapted to their sympatric major p lant host complex. Parasitoid strains may thus differ in their propens ity to search for a particular micro-habitat or host or they may diffe r in their physiological compatibility with particular plant or host s pecies. Cotesia flavipes Cameron, a larval parasitoid used worldwide i n biological control against tropical stemborers, has a wide host rang e in diverse habitats. The existence of plant and/or host specific str ains in C. flavipes has been postulated. To provide insight into the e xistence of strains in C. flavipes, we compared the plant/host complex selection behaviour, and physiological compatibility with different s temborers, of six different geographic strains of C. flavipes that dif fered in the plant/host complex they were obtained from. The results o f the host selection experiments indicate that there is no intraspecif ic variation in host selection behaviour among C. flavipes strains. Ho wever, our comparative experiments show variation in reproductive succ ess among strains. The most significant result was that the strain wit h the longest period of co-existence with the new host Diatraea saccha ralis Fabricius had the highest reproductive success on this host spec ies. We argue that the reported existence of C. flavipes strains is ba sed not on differences in host selection behaviour, but on differences in physiological compatibility between local parasitoid and host popu lation.