Effects of a Wild Wheat Genotype on Aphid-Parasitoid Interactions in the Geographic Center of Wheat Domestication

Domestication of wild plants to obtain agricultural cultivars is characterized by phenotypic changes that often affect herbivorous arthropods and their natural enemies. Selection for agronomically desirable traits often comes at the expense of plant defense, thus enhancing herbivore performance while hampering the activity of natural enemies. In the present study, we contrasted tri-trophic interactions on a wild and a cultivated wheat genotype, for the first time at the center of wheat domestication. Contrary to our hypothesis, a greenhouse experiment indicated that, at low aphid densities, the locally collected wild wheat genotype was more suitable for the bird cherry-oat aphid, Rhopalosiphum padi, than a domesticated wheat genotype. However, this was reversed at higher aphid densities; larger populations developed on the domesticated than on the wild plants in spite of a higher rate of parasitism by Aphidius colemani on the domesticated than the wild plants. Taken together, higher levels of biological control provided by the parasitoid may partially counteract high infestation of domesticated crops by the pestiferous aphids.