Response to enemies in the invasive plant Lythrum salicaria is genetically determined.
Response to enemies in the invasive plant Lythrum salicaria is genetically determined.
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DOI：
10.1093/aob/mcs076
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发表时间：
2012-11
期刊：
影响因子：
4.2
通讯作者：
Srijana Joshi;K. Tielbörger
中科院分区：
文献类型：
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作者：
Srijana Joshi;K. Tielbörger
背景和目的天敌释放假说假设入侵植物在进入新的范围时失去了它们共同进化的天敌。本研究测试，所提出的进化增加竞争能力（EICA）假说，是否逃避敌人的结果，在防御能力下降的植物从入侵范围。EICA的两个简单的方面进行了研究：（1）如果入侵者已经失去了他们的敌人和他们的防御，他们应该更负面的影响，其完整的自然入侵前草食动物谱比他们的本地同种;和（2）的遗传基础的进化变化，在入侵范围内的敌人释放没有得到充分考虑。方法将来自其原产地（欧洲）和入侵范围（北美）的多个种群的千屈菜（紫色千屈菜）暴露于原产地自然种群中的所有地上食草动物。该实验是用从田间收集的种子中培育的植物以及去除了母体效应的这些种子的后代进行的。关键结果绝对和相对叶片损害是高于引进比本地植物。尽管具有较小的高度增长率，入侵植物达到了一个更大的最终尺寸比本地人无论损害，表明大的耐受性，而不是有效的防御。起源对草食动物的反应和生长的影响在第二代植物中更强，这表明通过释放敌人的入侵潜力具有遗传基础。结论研究结果支持两个预测的EICA假说-一个遗传决定的本地和入侵植物之间的差异，在植物活力和对敌人的反应-和点的重要性，控制母体的影响，包括整个频谱的本地范围的敌人的实验。
BACKGROUND AND AIMS The enemy release hypothesis assumes that invasive plants lose their co-evolved natural enemies during introduction into the new range. This study tested, as proposed by the evolution of increased competitive ability (EICA) hypothesis, whether escape from enemies results in a decrease in defence ability in plants from the invaded range. Two straightforward aspects of the EICA are examined: (1) if invasives have lost their enemies and their defence, they should be more negatively affected by their full natural pre-invasion herbivore spectrum than their native conspecifics; and (2) the genetic basis of evolutionary change in response to enemy release in the invasive range has not been taken sufficiently into account. METHODS Lythrum salicaria (purple loosestrife) from several populations in its native (Europe) and invasive range (North America) was exposed to all above-ground herbivores in replicated natural populations in the native range. The experiment was performed both with plants raised from field-collected seeds as well as with offspring of these where maternal effects were removed. KEY RESULTS Absolute and relative leaf damage was higher for introduced than for native plants. Despite having smaller height growth rate, invasive plants attained a much larger final size than natives irrespective of damage, indicating large tolerance rather than effective defence. Origin effects on response to herbivory and growth were stronger in second-generation plants, suggesting that invasive potential through enemy release has a genetic basis. CONCLUSIONS The findings support two predictions of the EICA hypothesis - a genetically determined difference between native and invasive plants in plant vigour and response to enemies - and point to the importance of experiments that control for maternal effects and include the entire spectrum of native range enemies.