【摘要】 美洲大蠊不同发育阶段过冷却点由低到高依次为:20日龄卵、高龄若虫、雌虫、雄虫、低龄若虫、10日龄卵、5日龄卵、1日龄卵;不同发育阶段冰点由低到高依次为:低龄若虫、20日龄卵、雄虫、雌虫、高龄若虫、10日龄卵、5日龄卵、1日龄卵.卵的过冷却点和冰点随其日龄的增加而降低.在0、2、5、8℃亚致死低温下,低高龄若虫、雌虫和雄虫的存活时间随温度的升高而延长,不同虫期存活时间为:低龄若虫>高龄若虫>雌虫>雄虫.综合分析结果显示,美洲大蠊不同发育阶段的耐寒力为:高日龄卵>低龄若虫>高龄若虫>雌虫>雄虫.可见,卵、若虫期可能是温带地区越冬虫态.更多还原

【Abstract】 The supercooling points and freezing points of different developmental stages of American cockroach Periplaneta americana(Linnaens) were measured in a laboratory population.The sequence of supercooling points from low to high was twenty day-old eggs,old nymphae,female adults,male adults,young nymphae,ten day-old eggs,five day-old eggs,one day-old eggs.The sequence of freezing points from low to high was young nymphae,twenty day-old eggs,male adults,female adults,old nymphae,ten day-old eggs,five day-old eggs,one day-old eggs.The supercooling points and freezing points of eggs reduced gradually with its growth.The mean survival time of the insects exposed in low sublethal temperatures of 0,2,5 and 8 ℃ became longer as temperature increased.The mean survival time was young nymphae>old nymphae>female adults>male adults.It was showed that cold hardiness of different developmental stages of P.americana was old eggs>young nymphae>old nymphae>female adults>male adults.The results implied that P.americana may overwinter in egg or nympha stage in temperate zone.更多还原