菜粉蝶与其寄主植物金莲花

观察了用金莲花(TropaeolummajusL.)饲养的菜粉蝶PierisrapaeL.的发育情况,表明金莲花能使菜粉蝶完成世代发育,是其理想的寄主植物。国外有研究表明:将金莲花上取食的幼虫人为地转移到十字花科或其它寄主植物上,幼虫可正常取食,并最后发育为成虫;反之,将十字花科植物上取食的2龄至5龄的幼虫转移到金莲花上,则拒食外迁,最后全都饿死。然而,若将小麦胚芽人工饲料上饲养的幼虫转移到金莲花上,则幼虫正常取食。这是由于菜粉蝶幼虫在十字花科植物上取食的1龄阶段发展了对金莲花植株内所含的取食抑制化合物的敏感性,而在小麦胚芽人工饲料上取食的幼虫因一直接触取食抑制化合物而不对金莲花所含的取食抑制化合物产生敏感性之故。化学提取和昆虫行为实验证明,在金莲花中所含的取食抑制化合物的主要成分是绿原酸。

Cabbage white butterfly and its host plant nasturtium

Cabbage white butterfly Pieris rapae L. is an important pest insect of vegetables in the Cruciferae family, but is also found on garden nasturtium Tropaelum rnajus L which is in a different family. It was reported that larvaereared on nasturtium readily accepted cabbage as a host plant in each of the subsequent instars, and developed into normal adults, but when the second to fifth instar larvae were transferred from cabbage to nasturtium, they refused to feed and starved to death. On the other hand, larvae reared on a wheat germ diet accepted nasturtium as a host plant. Chemical analysis and behavioral tests demonstrated that there were strong feeding deterrents in nasturtium fohage, and chlorogenic acid was the most prominent active compound. Larvae apparently developed sensitivity to the deterrent as a result of feeding on the cabbage during its first instar, whereas continuous exposure to the deterrent causes habituation or suppression of sensitivity development.