Palatability to a generalist herbivore, defence and growth of invasive and native Senecio species: testing the evolution of increased competitive ability hypothesis
Palatability to a generalist herbivore, defence and growth of invasive and native Senecio species: testing the evolution of increased competitive ability hypothesis
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DOI：
10.1007/s00442-008-1182-z
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发表时间：
2009-02-01
期刊：
影响因子：
2.7
通讯作者：
Sans, F. X.
中科院分区：
文献类型：
--
作者：
Cano, Lidia;Escarre, J.;Sans, F. X.
本文检验了引入植物可能成为成功入侵者的预测，因为它们在新范围内经历了生长和防御方面的进化变化[竞争能力增强假说（EICA）的进化]。为蜗牛 Helix aspersa 提供种间和种内二元喂养选择。选择是：（1）源自引入范围（欧洲）种群的入侵性千里光（Senecio inaequidens）和千里光（Senecio pterophorus）植物，以及源自欧洲种群的三种本地物种（千里光（Senecio jacobea）、千里光（Senecio vulgaris）和千里光（Senecio malacitanus））植物； (2) 来自引入范围内的种群（欧洲）和本地范围内的种群（南非）的入侵性 S. inaequidens 和 S. pterophorus 植物。我们没有发现对本地或外来千里光物种的明显偏好模式。然而，我们发现欧洲入侵的 S. inaequidens 和 S. pterophorus 种群的适口性不如南非本土种群。此外，与 EICA 假说的预测相反，两个物种的入侵基因型也显示出更高的吡咯里西啶生物碱总浓度，并且就 S. inaequidens 而言，我们还发现比本地基因型有更高的生长。我们的结果是针对 EICA 假设的完善进行讨论的，该假设考虑了专业食草动物和通才食草动物之间以及定性防御和定量防御之间的差异。我们得出的结论是，S. inaequidens 和 S. pterophorus 的入侵种群不如本地种群适口，这表明可能会发生与建立相关的遗传分化，并通过在引入范围内选择防御最好的基因型来促进植物入侵的成功。
This paper tests the prediction that introduced plants may become successful invaders because they experience evolutionary changes in growth and defence in their new range [evolution of increased competitive ability hypothesis (EICA)]. Interspecific and intraspecific binary feeding choices were offered to the snail Helix aspersa. The choices were between: (1) plants of the invasive Senecio inaequidens and Senecio pterophorus derived from populations in the introduced range (Europe) and plants of three indigenous species (Senecio jacobea, Senecio vulgaris and Senecio malacitanus) from populations in Europe; (2) plants of the invasive S. inaequidens and S. pterophorus from populations in the introduced range (Europe) and from populations in the native range (South Africa). We did not find a clear pattern of preference for indigenous or alien species of Senecio. However, we found that European invasive populations of S. inaequidens and S. pterophorus were less palatable than South African native populations. Moreover, in contrast to the predictions of the EICA hypothesis, the invasive genotypes of both species also showed a higher total concentration of pyrrolizidine alkaloids, and in the case of S. inaequidens we also found higher growth than in native genotypes. Our results are discussed with respect to the refinement of the EICA hypothesis that takes into account the difference between specialist and generalist herbivores and between qualitative and quantitative defences. We conclude that invasive populations of S. inaequidens and S. pterophorus are less palatable than native populations, suggesting that genetic differentiation associated with founding may occur and contribute to the plants' invasion success by selecting the best-defended genotypes in the introduced range.