采用笼养方法研究了东亚飞蝗虫口密度和龄期对其由群居型向散居型转变的影响。结果表明,不同密度条件下饲养的蝗虫其由群居型转变成散居型的速度不一样。密度越高,转变的速度越慢;当密度过高时,即使由三龄期开始隔离也无法转变其生态型。将处于三龄期群居型蝗蝻在低密度下隔离,到四龄时为过渡型,到五龄和成虫时为群居型;而四龄期的群居型蝗蝻经隔离后,在五龄和成虫时仅偏向于群居型;五龄期的群居型蝗蝻经隔离后,在成虫时仍为群居型。所以,三龄期可能是东亚飞蝗由群居型向散居型转变的临界期。超过三龄,即使在低密度下也不易发生生态型转变。 The effects of pest population density and age of migratory locusts in East Asia on their change from social to diastrophism were studied using the method of caged cultivation. The results showed that the locusts fed under different densities had different rates of transformation from gregarious to diaspora. The higher the density, the slower the transition. When the density is too high, the ecotype can not be transformed even if it is isolated from the third instar. In the third instar gregarious locusts isolated at low density, to the fourth age as a transitional type, to the fifth instar and adult when the gregarious; and the fourth instar gregarious locusts isolated, at the fifth instar and adult Only biased towards the gregarious; the gregarious locusts of the fifth instar were still segregated when they were adults. Therefore, the third instar may be the critical period for the transformation of migratory locusts from social to diaspora. More than the third age, even in the low density is not prone to ecotype change.