Foraging parasitoids are sometimes confronted with variation among potential hosts, and must be able to quickly identify acceptable hosts to maximize foraging efficiency. The parasitoid Aphidius ervi (Hymenoptera: Braconidae) parasitizes both red and green color morphs of the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae). Although wasps have shown a preference for green aphids in past studies, they can successfully parasitize and develop in the red morph. We examined how experience impacts an ovipositing wasp's selection of either red or green aphids. We exposed female wasps to aphids of both colors simultaneously and observed each wasp for 20 minutes, classifying all encounters as host acceptance or rejection. We used bootstrap statistical techniques to assess whether a wasp attacking a particular color morph was more likely to attack an aphid of the same color in subsequent encounters than predicted by chance. We found that the initial color morph in any series of encounters influences A. ervi's subsequent encounters, suggesting that wasps may use prior experience to modify their foraging behavior. Behavioral plasticity and a propensity for associative learning may possibly help explain patterns of parasitism between red and green aphids in field observations.
Species 1: Hymenoptera Aphidiidae Aphidius ervi
Species 2: Homoptera Aphididae Acyrthosiphon pisum (pea aphid)
Keywords: foraging behavior, parasitoid
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