Early adult learning affects host preferences in the tephritid parasitoid Psyttalia concolor (Hymenoptera: Braconidae)

Parasitic wasps rely on a hierarchy of stimuli to locate their hosts. Olfactory cues from the natal host complex affect parasitoid preferences and can be learned by parasitoids during larval stages and the early adult stage. While the existence of pre-imaginal conditioning has been documented in several braconid aphid parasitoids, no evidence has yet been provided for parasitic wasps attacking Tephritidae. Psyttalia concolor (Hymenoptera: Braconidae) is a koinobiont larval–pupal endoparasitoid of tephritid flies. In this study, we evaluated the influence of larval and early adult experience on subsequent host seeking in P. concolor females. Parasitoids were reared using Ceratitis capitata or Bactrocera oleae larvae as hosts, and emerging wasp adults were tested for host preferences in two-choice bioassays. P. concolor females preferred to oviposit in, and had higher oviposition success rates on the natal host. When P. concolor females were excised from their host puparia, preventing them from chewing emergence holes, they lost their natal host preference, solidifying the evidence of early adult learning for host selection. This study adds to the growing body of basic knowledge on braconid host-location behavior. From an applied point of view, training procedures for early adult learning has potential for use in mass rearing of parasitoids employed in biological control programs against tephritid flies.