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油松毛虫(Dendrolimus tabulaeformis Tsai et Liu)为我国华北地区的重要森林害虫。它在北京西山地区每年发生1—2代,以发生两代者为多数。产生世代分化的原因,是由于在第一代幼虫期出现滞育的缘故。在北京西山地区,油松毛虫的滞育出现于第一代四龄幼虫时,每年7月下旬前后,经过三次蜕皮的幼虫,假如体色变化不大,身体未见显著增长,取食量小,生长发育迟缓,即为滞育状态的幼虫,当年它不能完成第一代。反之,蜕皮后幼虫体色变为深黑,间有黄色斑点,色泽鲜艳,食量显著增加,生长发育迅速,即为正常幼虫,当年可以结茧化蛹而产生第二代。 根据我们连续几年的观察,如将第一年出现滞育的幼虫,进行个体饲育,至第二年其产生的后代,有的在第一
Dendrolimus tabulaeformis Tsai et Liu is an important forest pest in North China. It occurs 1-2 generations a year in Xishan district of Beijing, taking the occurrence of two generations to majority. The reason for generation differentiation is due to diapause in the first generation larvae. In the Xishan area of Beijing, diapause occurs on the fourth instar larvae of the first generation. After three larvae of molting around the end of July each year, no significant increase in body color and little food intake , Growth retardation, larvae that is diagonal state, when it can not complete the first generation. On the contrary, after molting larva body color turned dark black, between the yellow spots, bright color, food intake increased significantly, rapid growth and development, that is normal larvae, when the cocoon pupate can produce the second generation. According to our observations for several years, such as the first year of diapause larvae, individual breeding, to the second year of its generation of offspring, and some in the first