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通过对新疆北部棉区二、三代棉铃虫各发育阶段的存亡数量及其致死因子的系统观察和研究 ,组建了新疆北部棉区二、三代棉铃虫自然种群生命表。新疆北部棉区二代棉铃虫消亡率为 9 7.5 % ,种群趋势指数 (I) =3.35 3。三代棉铃虫消亡率为 94.2 7% ,二、三代棉铃虫卵期和低龄幼虫 (1～ 3龄 )消亡率为 79.61%和 78.8%。 4～ 6龄消亡率分别为 18.71%和 14.5 9%。对照 Price(1975 )所概括植食性昆虫自然种群生命表的两种基本类型 ,新疆北部棉区二、三代棉铃虫均属 A型。新疆北部棉区棉铃虫消亡因子可归纳为捕食、寄生、自然损失、生理死亡、人工打顶五个因子 ,天敌捕食和寄生是主要消亡因子。各发育阶段消亡率差异总体较小 ,天敌捕食是卵期和低龄幼虫 (3龄以前 )消亡的主导因子 ,而天敌寄生则是 4～ 6龄幼虫消亡的主导因子
Through the systematic observation and research on the survival numbers and the lethal factors of the second and third generation cotton bollworms in the northern cotton area of Xinjiang, the second and third generation cotton bollworm natural population life tables were established in the northern cotton area of Xinjiang. The second generation cotton bollworn population in the northern part of Xinjiang had a mortality rate of 9 7.5% and its population trend index (I) was 3.35 3. Three generations of cotton bollworm demise rate of 94.2 7%, two and three generations of cotton bollworm oviparous and young larvae (1 ~ 3 age) the demise rate of 79.61% and 78.8%. The demise rates of 4 to 6 years old were 18.71% and 14.59% respectively. In contrast to the two basic types of natural population life tables of herbivorous insects summarized in Price (1975), cotton bollworms of the second and third generation in northern cotton area of Xinjiang are Type A. The extinction factors of cotton bollworm in northern cotton area of Xinjiang can be summarized as predation, parasitism, natural loss, physiological death and artificial topping five factors. Predation and parasitism of natural enemies are the main extinction factors. Differences in the rate of demise of each stage of development were generally small. Predation by natural enemies was the dominant factor in the disappearance of oviparous and young larvae (3rd instar), while the predation of 4 ~ 6 instar larvae