van Baaren J, Le Lann C, Pichenot J, Pierre J S, Krespi L, Outreman Y
UMR 1099 INRA-Agrocampus Ouest-Université Rennes I, Avenue du Général Leclerc, 35042 Rennes cedex, France.
Bull Entomol Res. 2009 Jun;99(3):299-306. doi: 10.1017/S0007485308006342. Epub 2008 Dec 9.
Three related Aphidius parasitoid species share the same host, the grain aphid Sitobion avenae. Among this parasitoid community, Aphidius rhopalosiphi is the most abundant species in the field. Both the interspecific host discrimination of A. rhopalosiphi towards hosts parasitized by the two other species (i.e. A. avenae and A. ervi) and the interspecific host discrimination of the two other species towards hosts parasitized by A. rhopalosiphi were studied here. Results showed that females of A. rhopalosiphi and A. avenae both discriminated between unparasitized hosts and hosts parasitized by the other species. This discrimination occurred only after ovipositor insertion, suggesting the perception of an internal marker of parasitism. Likewise, females of A. rhopalosiphi and A. ervi were able to discriminate between unparasitized hosts and hosts parasitized by the other species. However, in this combination of species, recognition of parasitized hosts occurred before ovipositor insertion, through an antennal perception, suggesting the presence an external cue indicating parasitism. Hence, interspecific host discrimination in the three Aphidius species is based on internal or external cues, which are used either alone or together. Our results showed that the cues used for interspecific host discrimination depend on the specific identity of the interaction. These differences seemed strongly linked to the way the different species respond to defensive behaviours of their aphid hosts. Results are discussed in the context of optimal foraging and possible consequences for community structure.
三种相关的蚜茧蜂寄生蜂物种共享同一个宿主——麦长管蚜。在这个寄生蜂群落中，燕麦蚜茧蜂是田间数量最多的物种。本文研究了燕麦蚜茧蜂对被其他两种物种（即燕麦蚜茧蜂和豌豆蚜茧蜂）寄生的宿主的种间宿主识别，以及其他两种物种对被燕麦蚜茧蜂寄生的宿主的种间宿主识别。结果表明，燕麦蚜茧蜂和麦蚜茧蜂的雌蜂都能区分未被寄生的宿主和被其他物种寄生的宿主。这种识别仅在产卵器插入后才会发生，这表明存在对寄生内部标记的感知。同样，燕麦蚜茧蜂和豌豆蚜茧蜂的雌蜂也能够区分未被寄生的宿主和被其他物种寄生的宿主。然而，在这种物种组合中，通过触角感知，在产卵器插入之前就能识别被寄生的宿主，这表明存在一种表明寄生的外部线索。因此，三种蚜茧蜂物种的种间宿主识别基于内部或外部线索，这些线索可以单独使用或一起使用。我们的结果表明，用于种间宿主识别的线索取决于相互作用的具体物种。这些差异似乎与不同物种对其蚜虫宿主防御行为的反应方式密切相关。本文在最优觅食的背景下讨论了这些结果以及对群落结构可能产生的影响。
