Habitat Preferences of Three Congeneric Braconid Parasitoids: Implications for Host-Range Testing in Biological Control

Abstract

Abstract Cotesia flavipes, C. sesamiae, and C. chilonis are parasitoids of stemboring noctuids and pyralids of gramineous plants. We tested the response of these parasitoids to volatiles from a range of host and nonhost grasses and volatiles from nongrass, nonhost plants. We found that the three species were differentially attracted to grasses and that their preference patterns were consistent with host/host–plant records from the field. None of the three species was attracted to volatiles from nongrass plants. For two of the three parasitoids, grasses that were damaged by a host were more attractive than undamaged grasses and damaged, previously less-favored grasses became more attractive than undamaged, previously favored grasses. Damage by a host did not increase the attraction of nongrass plants to parasitoids. We suggest that, for certain parasitoids, testing preference for habitat plants could help to determine their ecological host range and therefore aid in matching parasitoids to target crops, as well as streamlining testing for impacts against nontarget species.