烟蚜茧蜂种内寄主识别与内部竞争
Intraspecific host discrimination and intrinsic competition in parasitoid Aphidius gifuensis Ashmead (Hymenoptera: Braconidae: Aphidiinae)

为明确寄生桃蚜Myzus persicae（Sulzer）的单性内寄生蜂烟蚜茧蜂Aphidius gifuensis Ashmead的种内识别与内部竞争，研究测定不同寄主密度对烟蚜茧蜂雌蜂卵的分布影响，以及不同产卵时间间隔对自身和同种寄主识别、种内内部竞争的影响。结果显示，烟蚜茧蜂在寄主密度为30头以下时，过寄生率高于31.16%；而寄主密度为50头以上时，过寄生率低于6.64%。在24 h以上的产卵时间间隔下，烟蚜茧蜂的自身过寄生率高于37.04%，而同种过寄生率在22.45%~25.93%之间；而且龄期较高的幼虫在种内内部竞争中获胜的概率高于72.00%。表明烟蚜茧蜂在低寄主密度下倾向于过寄生，在高寄主密度下有避免过寄生的趋势；烟蚜茧蜂倾向于自身过寄生，而对同种过寄生表现出一种产卵限制；在烟蚜茧蜂的种内内部竞争中，龄期较高的幼虫一般具有优势。
To clarify the intraspecific host discrimination and intrinsic competition in parasitoid Aphidius gifuensis Ashmead parasitizing the green peach aphid, Myzus persicae (Sulzer), the influence of host density on egg distribution was determined, and the effects of different time intervals of oviposition on self- and conspecific discrimination and intraspecific intrinsic competition were also studied. The results demonstrated that at ≤30 host density, superparasitism percentages of A. gifuensis were more than 31.16%; at ≥50 host density, superparasitism percentages were less than 6.64%. At ≥24 h interval, selfsuperparasitism percentages of A. gifuensis were more than 37.04%, while conspecific superparasitism percentages were 22.45%-26.32%, and the winning probabilities of the older larvae were more than 72.00%. Therefore, A. gifuensis tended to superparasitize green peach aphids at low host density, whereas it had a tendency to avoid superparasitism at higher host density. A. gifuensis tended to superparasitize aphids previously parasitized by itself, while this parasitoid showed an oviposition restraint to conspecific superparasitism. In intraspecific intrinsic competitions, the older larvae of this parasitoid commonly had superiority.