摘要
在室内,以小菜蛾3龄幼虫为寄主,对过寄生后,小菜蛾重要内寄生蜂——半闭弯尾姬蜂的种内竞争进行了研究.当2头雌蜂同时寄生(10 min内)同1头小菜蛾,几乎同时孵化的姬蜂幼虫间总是先发现对手的1龄幼虫抢先利用角质化上颚将其他竞争者攻击致死.当2次寄生时间间隔为24,48,72,96 h时,多以先寄生的姬蜂幼虫在发育上占据优势,它通过物理攻击将后产的初孵幼虫杀死,或直接攻击蜂卵致使包囊、黑化的发生,并可通过生理抑制完全阻碍后产蜂卵的发育.当2次寄生间隔时间长达120 h,后孵化的姬蜂1龄幼虫可通过上颚将先寄生的已发育为末龄的无上颚的姬蜂幼虫致伤或杀死.研究结果表明,当种内竞争发生时,半闭弯尾姬蜂可通过物理攻击和生理抑制2种途径将同类竞争者排除.竞争结果与雌蜂2次寄生的时间间隔有关.
Intraspecific competition of larvae in superparasitism was investigated in Diadegma semiclausum Hellén（Hymenoptera： Ichneumonidae）,a solitary endoparasitoid of Plutella xylostella（L.）（Lepidoptera： Plutellidae） larvae under laboratory conditions,by exposing the third-instar host larvae to female wasps. Lethal symmetrical competition by physical combats with mandibles occurred between first-instar larvae just after hatching when two eggs were laid almost simultaneously into the same host larvae within 10 mins.In asymmetrical competition,a host larva was parasitized by two female wasps in succession at intervals of 24,48,72,and 96 h,and older larvae usually have an advantage over younger ones.They tended to win against younger ones through physical attacks leading to encapsulation and melanization formation of newly hatched first-instar larvae or eggs,even through physiological suppression to prevent from the development of the second laid eggs.However,during competition between first-and amandibulate last instar larvae oviposited at an interval of 120 h,the first instar larvae sometimes killed older ones by physical attacks using the mandibles.The results suggest that D.semiclausum generally make use of physical combat and physiological suppression to eliminate competitors in intraspecific competition.The outcome of competition principally depended on the time interval between two ovipositions by conspecific females.
出处
《河南农业大学学报》
CAS
CSCD
北大核心
2010年第4期432-437,共6页
Journal of Henan Agricultural University
基金
国家自然科学基金项目(30471168)
关键词
种内竞争
过寄生
半闭弯尾姬蜂
小菜蛾
intraspecific competition
superparasitism
Diadegma semiclausum
Plutella xylostella
