The degradation of chitin by chitinase was vital step in the life cycle of insects because insects undergo periodic ecdysis and metamorphosis 几丁质代谢随昆虫不同生长发育阶段而变化并保持相对的稳定，对昆虫的正常的生长发育是至关重要的。
2.
Transgenic bt cotton mainly affect high - instar larvae by retarding the growth and intering the proceeding of ecdysis , pupation , and eclosion . the growth retardation leads to the postponement of growth period duration ( the showed that growth period duration prolonged 17 days ) . feeding the larvae with the tissue of the transgenic bt cotton and the moths with the flower of transgenic bt cotton , the number of eggs and hatching rate decreased obverviously 转基因药防田中，天敌昆亚群落的个体数占整个昆虫群落总个体数的10 . 0 % ，其优势种为蜘蛛类、七星瓢虫( coceinellas叩te即uneitatalinnaeus ) 、龟纹瓢虫( prol ， laea少只ponjcagoeze ) 、大眼蝉长蜷( prqp . ylaeajaponicagoeze )和草岭(助rys叩asepre即unetatawesmael ) 。
