The effect of direct and indirect defenses in two wild brassicaceous plant species on a specialist herbivore and its gregarious endoparasitoid
The effect of direct and indirect defenses in two wild brassicaceous plant species on a specialist herbivore and its gregarious endoparasitoid
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DOI：
10.1111/j.1570-7458.2008.00681.x
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发表时间：
2008-07-01
影响因子：
1.9
通讯作者：
Harvey, Jeffrey A.
中科院分区：
文献类型：
--
作者：
Gols, Rieta;Witjes, Leontien M. A.;Harvey, Jeffrey A.
大多数关于植物对植食性昆虫防御的研究独立地研究了植物的直接防御和间接防御。然而，这些防御并不一定是相互排斥的。植物代谢产物可以通过食物链传播，也可以影响食草动物的天敌。当一个天敌被吸引到一个植物上时，就其自身的适应性而言，一个冲突可能会出现。此外，植物防御经常在人工选择可能导致对食草昆虫抗性降低的栽培植物物种中进行研究。在这项研究中，我们调查了两个密切相关的野生十字花科植物物种，黑芥L。和白芥Sinapis arvensis L.菜粉蝶Pieris brassicae L.（鳞翅目：粉蝶科），这是专门的十字花科植物物种，发育快，达到较高的蛹质量时，饲养在B。nigra比S.阿文西斯与此相反，Cotesia glomerata L.（膜翅目：Braconidae），这是一个群居的内寄生的P. brassicae的毛虫，发展同样良好的P. brassicae无论其寄主的食物植物饲养。寄生蜂幼虫的取食策略，即选择性地取食血淋巴和脂肪体，可能允许更广泛的主机大小范围，而不影响大小或发育时间的新兴寄生蜂。在飞行舱实验中，C. glomerata在取食布鲁塞尔芽的寄主上有产卵经验，对寄主受损的B表现出明显的偏好。nigra在宿主受损的S.野生植物顶空分析揭示了两种植物挥发性排放量的定量和定性差异。这种寄生蜂可能会使用一系列与宿主和宿主的食用植物相关的线索，以识别宿主可以食用的不同植物物种。这些结果表明，这种植物-寄主-寄生物复合体的直接和间接植物防御之间没有冲突。
Most studies on plant defenses against insect herbivores investigate direct and indirect plant defenses independently. However, these defenses are not necessarily mutually exclusive. Plant metabolites can be transmitted through the food chain and can also affect the herbivore's natural enemies. A conflict may arise when a natural enemy is attracted to a plant that is suboptimal in terms of its own fitness. In addition, plant defenses are often studied in cultivated plant species in which artificial selection may have resulted in reduced resistance against insect herbivores. In this study, we investigated both direct and indirect plant defenses in two closely related wild brassicaceous plant species, Brassica nigra L. and Sinapis arvensis L. The herbivore Pieris brassicae L. (Lepidoptera: Pieridae), which is specialized on brassicaceous plant species, developed faster and attained higher pupal mass when reared on B. nigra than on S. arvensis. In contrast, Cotesia glomerata L. (Hymenoptera: Braconidae), which is a gregarious endoparasitoid of P. brassicae caterpillars, developed equally well on P. brassicae irrespective of the food plant on which its host had been reared. The feeding strategy of the parasitoid larvae, that is, selectively feeding on hemolymph and fat body, is likely to allow for a much wider host-size range without affecting the size or development time of the emerging parasitoids. In flight chamber experiments, C. glomerata, which had an oviposition experience in a host that fed on Brussels sprout, exhibited significant preference for host-damaged B. nigra over host-damaged S. arvensis plants. Headspace analysis revealed quantitative and qualitative differences in volatile emissions between the two plant species. This parasitoid species may use a range of cues associated with the host and the host's food plant in order to recognize the different plant species on which the host can feed. These results show that there is no conflict between direct and indirect plant defenses for this plant-host-parasitoid complex.