Habit Preferences and Fidelity in the Cotesia Flavipes Complex (Hymenoptera: Braconidae): Current Preferences and the Potential for Change Through Learning and Selection
Knowing the host range of a biological control agent is crucial to increasing the probability of controlling a target pest, and to decreasing the possibility of injuring non-target hosts. Here I suggest that testing habitat preference can help predict host ranges of insect parasitoids, and I present the results from tests of three congeneric braconid parasitoids in the Cotesia flavipes complex. These wasps parasitize stemboring larvae (Lepidoptera: Pyralidae & Noctuidae) in grasses and have been used as biological control agents in sugar cane and maize. I show that each of the parasitoids has distinct responses to different grass types and that some grasses are preferred to others. Furthermore, I show that, for these three parasitoids, non-target hosts in non-grass habitats are unlikely to be affected by these parasitoids, but that non-target hosts in grasslands of concern might be at risk. I then examine two potential routes for change in the plant preferences of these parasitoids; learning and evolutionary change. I show that the hostplant of their larval host is unlikely to change the plant preferences of the adult wasp. Moreover, through an artificial selection regimen, I show that these wasps are unlikely to shift plant preferences through natural selection. Given my results, I argue that laboratory testing can yield a useful, and accurate picture of parasitoid behavior prior to release, and that this picture is unlikely to change after the parasitoid is released.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign