Department of Entomology, Nanjing Agriculture University, Nanjing 210095, China.
J Insect Sci. 2011;11:81. doi: 10.1673/031.011.8101.
Few empirical studies have directly explored the association between Buchnera aphidicola (Enterobacteriales: Enterobacteriaceae), the primary endosymbiont of aphids, and the life history strategies of aphid parasitoids. A series of paired-choice experiments were conducted to explore the preference of the parasitoid Lysiphlebus ambiguus Halliday (Hymenoptera: Aphididae) for symbiotic and aposymbiotic Aphis fabae Scopoli (Hemiptera: Aphididae) and the suitability of these hosts for parasitoid development. When given a choice between symbiotic and aposymbiotic aphids of the same instar, the parasitoid significantly preferred symbiotic over aposymbiotic aphids only during the later instars (L(4) and adult). The suitability of aposymbiotic aphids for parasitoid development was equal to that of symbiotic aphids in terms of survivorship and sex ratio, but was significantly lower than that of symbiotic aphids for L(4) and adult instars in development rate and/or female adult size. When given a choice between similar-sized symbiotic L(2) and aposymbiotic L(4) aphids, the parasitoid preferred the former. No significant differences in preference or host suitability were demonstrated when the parasitoid was given a choice between different instars of aposymbiotic aphids. While parasitoid lifetime fecundity increased with aphid instar at the time of oviposition, there was no significant influence of previous development from symbiotic versus aposymbiotic aphids. These results suggest that while L. ambiguus can discriminate between symbiotic and aposymbiotic A. fabae during later instars and when the aphids are of a similar size, the primary endosymbiont is not needed for successful parasitoid development; and its absence only compromises parasitoid growth reared from later instar aposymbiotic host.
很少有实证研究直接探讨 Buchnera aphidicola（肠杆菌目：肠杆菌科），即蚜虫的主要内共生体，与蚜虫的生活史策略之间的关系。我们进行了一系列配对选择实验，以探究寄生蜂 Lysiphlebus ambiguus Halliday（膜翅目：蚜科）对共生和非共生的豆蚜 Aphis fabae Scopoli（半翅目：蚜科）的偏好，以及这些宿主对寄生蜂发育的适宜性。当给予同一龄期的共生和非共生蚜虫供选择时，寄生蜂仅在后期龄期（L(4)和成虫）显著偏爱共生蚜虫而非非共生蚜虫。从生存率和性别比例来看，非共生蚜虫对寄生蜂发育的适宜性与共生蚜虫相等，但在发育速度和/或雌性成虫大小方面，非共生蚜虫显著低于共生蚜虫。当给予相似大小的共生 L(2)和非共生 L(4)蚜虫供选择时，寄生蜂更喜欢前者。当给予非共生蚜虫不同龄期供选择时，寄生蜂既没有表现出偏好差异，也没有表现出宿主适宜性差异。尽管寄生蜂的一生总产卵量随蚜虫龄期的增加而增加，但以前由共生蚜虫或非共生蚜虫发育对其无显著影响。这些结果表明，虽然 L. ambiguus 可以在后期龄期和当蚜虫大小相同时区分共生和非共生的 A. fabae，但内共生体并不是成功寄生发育所必需的；而且它的缺失仅会影响从后期龄期非共生宿主中饲养的寄生蜂的生长。
