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题目材料：
Domesticated crops have long been observed to differ strongly from their wild progenitors in morpbological traits (form and struicture). The enlargement of specific plant structures is the most widely emphasized of all of the changes that arise from domestication. Striking examples of gigantism can be found by comparing crops such as tomato(Lvcopersicim esculent), maize (Zea moys), beans(Phaseolus vulgaris), artichokes(Cnara carhnculus var.scohmns), sunflower(Helianthes anmn),and squash(Cucurbita pepo)with their wild ancestors.The plant vigor hypothesis proposed by Price predicts that insect herbivores will tend tooviposit [lay eggs]on plant organs that grow faster and larger.Researchers found some support for this idea.For instance. in domesticated sunflowers, increased flower size from domestication is positively correlated with landing and egg-laying effort of female sunflower moths, Homoeosoma electellum, but increased seed size is negatively associated with parasitoid accessibility to H.electellum larvae. As a result, selection for gigantism may interfere with natural control and explain the observation that H. electellum is parasitized less frequently in sunflower agroecosystems than in natural sunflower ecosystems However, parasitoids have a slightly greater effect on the banded sunflowwer moth. Cochylis hospes, which has a life history sumilar to that of H.electellum.Therefore, the life history of natural enemies and herbivores may influence whether selection for gigaatism could result in enemy-free space for herbivores.
以上解析由 考满分老师提供。
