Center for Ecological ResearchKyoto University2-509-3 Hirano, Otsu, Shiga 520-2113, Japan; The Hakubi Center for Advanced ResearchKyoto UniversityYoshida Ushinomiya, Sakyo-ku, Kyoto 606-8501, Japan.
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam Kruislaan 320, 1098SM Amsterdam, The Netherlands.
R Soc Open Sci. 2015 Dec 2;2(12):150524. doi: 10.1098/rsos.150524. eCollection 2015 Dec.
When deciding where to oviposit, herbivorous insects consider: (i) the plant's value as a food source, (ii) the risks of competing with con- and heterospecific herbivores, and (iii) the risks of parasitism and predation on the host plant. The presence of con- and/or heterospecific competitors would further affect the oviposition preference, because the preceding herbivores induce direct/indirect defences in plants against forthcoming herbivores, and thereby alter oviposition decisions. In previous studies, the abovementioned factors have not been studied in an integrative manner. We performed here a case study of this by assessing the oviposition preferences of a small white butterfly, Pieris rapae, for plants occupied by combinations of conspecific larvae, heterospecific larvae (Plutella xylostella), specialist parasitoids of Pi. rapae (Cotesia glomerata) and generalist predators (ants). We previously reported that the females showed equal preference for Pl. xylostella-infested and uninfested plants. Here, we showed that Pi. rapae females preferred uninfested plants to conspecific-infested ones, and Pl. xylostella-infested plants to Pi. rapae-infested ones. We discuss these oviposition preferences of Pi. rapae females in the framework of costs and benefits of interspecific herbivore associations from the above point of view.
当决定在哪里产卵时，食草昆虫会考虑：（i）植物作为食物来源的价值，（ii）与同-和异-种食草动物竞争的风险，以及（iii）寄生和捕食宿主植物的风险。同-种和/或异-种竞争者的存在将进一步影响产卵偏好，因为前面的食草动物会诱导植物对即将到来的食草动物产生直接/间接防御，从而改变产卵决策。在以前的研究中，上述因素没有以综合的方式进行研究。我们通过评估小菜粉蝶（Pieris rapae）对被同-种幼虫、异-种幼虫（小菜蛾（Plutella xylostella））、小菜粉蝶的专性寄生蜂（Cotesia glomerata）和一般捕食者（蚂蚁）占据的植物的产卵偏好，对这种情况进行了案例研究。我们之前报告说，雌性对 Pl. xylostella 感染和未感染的植物表现出同等的偏好。在这里，我们表明，Pi. rapae 雌性更喜欢未感染的植物而不是同-种感染的植物，更喜欢 Pl. xylostella 感染的植物而不是 Pi. rapae 感染的植物。我们从上述角度讨论了 Pi. rapae 雌性的这些产卵偏好与种间食草动物关系的成本和收益。
