Effect of Sequential Learning Experiences on Searching Responses and Sex Ratio Allocations of the Gregarious Insect Parasitoid, Cotesia congregata (Say) (Hymenoptera: Braconidae)

We investigated the effects of sequential adult learning experiences (postemergence + ovipositional) with two host foodplants (tomato and/or tobacco) on searching responses, clutch size, and sex ratio allocations of Cotesia congregata, a gregarious endoparasitoid of Manduca sexta. Sequential experiences with one host foodplant resulted in a stronger searching response to the plant experienced and a higher proportionate allocation of females to hosts offered with this plant. Sequential experiences with both plants resulted in similar searching responses to the two plants and similar proportionate allocations of females, irrespective of the order in which plants were experienced. Ovipositional experience resulted in a stronger searching response to the plant experienced but effects on sex ratio allocations were not definitive. Clutch size was not modified by experience. Results demonstrate that parasitic wasps can learn multiple host-associated plant cues and suggest that sequential learning experiences serve to define the effective host foodplant range.