Herbivores may mediate their vulnerability to parasitism by exploiting variability in plant characteristics. Changes to plant characteristics, for example through crop domestication, may alter patterns of parasitism and ultimately, parasitoid impact. The sunflower moth, Homoeosoma electellum, experiences lower parasitism rates when feeding on agricultural sunflowers than on wild sunflowers. To assess the presence of a structural refuge from parasitism, we studied the foraging activity of Dolichogenidea homoeosomae, the major parasitoid of the moth in California, in relation to the feeding behavior of the larvae. We found that larvae feeding among the seeds were less likely to be parasitized than those feeding on florets. Furthermore, a higher proportion of larvae fed within the seed layer on agricultural flowers, indicating that larvae are more able to exploit enemy-free space and therefore escape parasitism on agricultural sunflowers.
Species 1: Lepidoptera Pyralidae Homoeosoma electellum (sunflower moth)
Species 2: Hymenoptera Braconidae Dolichogenidea homoeosomae
Species 3: Asteridales Asteraceae Helianthus annuus (sunflower)
Keywords: enemy-free space, tritrophic interactions
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA