Learning in the Generalist Tachinid Parasitoid Exorista Mella Walker (Diptera: Tachinidae)
Many parasitoids have been shown to learn visual and/or olfactory cues associated with hosts. In contrast to the Hymenoptera, learning in dipteran parasitoids is relatively unstudied. This study explores the ability of a polyphagous tachinid, Exorista mella, to learn to associate visual and olfactory cues with hosts. In an experiment involving colored host models, flies trained on models of one color were subsequently attracted more strongly to models of the color that they had not experienced. The unsuitability of these models as hosts suggested that the flies may have engaged in avoidance learning. Flies demonstrated the ability to learn to associate colored disks with hosts. A separate experiment demonstrated that flies responded to volatile plant compounds but failed to find evidence for odor learning. Learning of host-associated cues by E. mella may allow this generalist parasitoid to take advantage of locally abundant host populations and maintain host-searching efficiency in an environment.
Stireman, J. O.
(2002). Learning in the Generalist Tachinid Parasitoid Exorista Mella Walker (Diptera: Tachinidae). Journal of Insect Behavior, 15 (5), 689-706.