When beetle Aulacophora femoralis chinensis Weise fed on cucumber seedlings, it first chewed a circular trench on their leaves and then nibbled the leaf tissues iso-lated by the trench, but when it was fed with the de...When beetle Aulacophora femoralis chinensis Weise fed on cucumber seedlings, it first chewed a circular trench on their leaves and then nibbled the leaf tissues iso-lated by the trench, but when it was fed with the detached fresh cotyledons of cucumber, such an interesting trenching behavior did not occur, which indicated that the feeding be-havior of the beetle was obviously correlated with the chemical response of the cucumber to the herbivory. Within 60 min after feeding, the level of cucurbitacin C in fed coty-ledons of the cucumber seedling increased 10 fold or more. Cucurbitacin I was also detected 15 min after feeding, which reached 75 mg/g within 60 min. The high levels of cucurbi-tacins C and Ⅰ in fed cotyledons could be maintained for at least 24 h. A. femoralis chinensis was strongly stimulated to take food by cucurbitacin C at a concentration between 10 and 250 mg/g, and the feeding deterrent activity was observed at >250 mg/g, while the feeding deterrent threshold of A. femoralis chinensis to cucurbitacin I was 50 mg/g. The mix-ture of cucurbitacins C and Ⅰ had a much stronger feeding deterrent activity than single cucurbitacin I. The results suggested that cucumber could elicit chemical response to the beetle herbivory, its leaf being induced to produce more kinds of cucurbitacins and make them reach the levels of feeding deterrent activity on the beetle, while the trenching behavior of A. femoralis chinensis was its strategy to answer the chemical response of cucumber. The trenching behavior of the beetle not only stopped the cucurbitacins biosynthesis in cucumber leaf tissues, but also blocked the translocation of cucurbitacins to the feeding sites. The trenching behavior of the beetle and the chemical response of host cucumber were the mutual adaptive strategies for protecting the host plant and the beetle themselves.展开更多
文摘When beetle Aulacophora femoralis chinensis Weise fed on cucumber seedlings, it first chewed a circular trench on their leaves and then nibbled the leaf tissues iso-lated by the trench, but when it was fed with the detached fresh cotyledons of cucumber, such an interesting trenching behavior did not occur, which indicated that the feeding be-havior of the beetle was obviously correlated with the chemical response of the cucumber to the herbivory. Within 60 min after feeding, the level of cucurbitacin C in fed coty-ledons of the cucumber seedling increased 10 fold or more. Cucurbitacin I was also detected 15 min after feeding, which reached 75 mg/g within 60 min. The high levels of cucurbi-tacins C and Ⅰ in fed cotyledons could be maintained for at least 24 h. A. femoralis chinensis was strongly stimulated to take food by cucurbitacin C at a concentration between 10 and 250 mg/g, and the feeding deterrent activity was observed at >250 mg/g, while the feeding deterrent threshold of A. femoralis chinensis to cucurbitacin I was 50 mg/g. The mix-ture of cucurbitacins C and Ⅰ had a much stronger feeding deterrent activity than single cucurbitacin I. The results suggested that cucumber could elicit chemical response to the beetle herbivory, its leaf being induced to produce more kinds of cucurbitacins and make them reach the levels of feeding deterrent activity on the beetle, while the trenching behavior of A. femoralis chinensis was its strategy to answer the chemical response of cucumber. The trenching behavior of the beetle not only stopped the cucurbitacins biosynthesis in cucumber leaf tissues, but also blocked the translocation of cucurbitacins to the feeding sites. The trenching behavior of the beetle and the chemical response of host cucumber were the mutual adaptive strategies for protecting the host plant and the beetle themselves.
