König Malin A E, Lehtilä Kari, Wiklund Christer, Ehrlén Johan
Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden.
School of Natural Science, Technology and Environmental Studies, Södertörn University, Huddinge, Sweden.
PLoS One. 2014 Jun 19;9(6):e99333. doi: 10.1371/journal.pone.0099333. eCollection 2014.
Plants have two principal defense mechanisms to decrease fitness losses to herbivory: tolerance, the ability to compensate fitness after damage, and resistance, the ability to avoid damage. Variation in intensity of herbivory among populations should result in variation in plant defense levels if tolerance and resistance are associated with costs. Yet little is known about how levels of tolerance are related to resistance and attack intensity in the field, and about the costs of tolerance. In this study, we used information about tolerance and resistance against larval herbivory by the butterfly Anthocharis cardamines under controlled conditions together with information about damage in the field for a large set of populations of the perennial plant Cardamine pratensis. Plant tolerance was estimated in a common garden experiment where plants were subjected to a combination of larval herbivory and clipping. We found no evidence of that the proportion of damage that was caused by larval feeding vs. clipping influenced plant responses. Damage treatments had a negative effect on the three measured fitness components and also resulted in an earlier flowering in the year after the attack. Tolerance was related to attack intensity in the population of origin, i.e. plants from populations with higher attack intensity were more likely to flower in the year following damage. However, we found no evidence of a relationship between tolerance and resistance. These results indicate that herbivory drives the evolution for increased tolerance, and that changes in tolerance are not linked to changes in resistance. We suggest that the simultaneous study of tolerance, attack intensity in the field and resistance constitutes a powerful tool to understand how plant strategies to avoid negative effects of herbivore damage evolve.
耐受性，即受损后补偿适合度的能力；抗性，即避免受损的能力。如果耐受性和抗性与成本相关，那么不同种群间食草动物侵害强度的差异应该会导致植物防御水平的差异。然而，对于田间耐受性水平如何与抗性及侵害强度相关，以及耐受性的成本，我们知之甚少。在本研究中，我们利用了在受控条件下蝴蝶Anthocharis cardamines对幼虫食草的耐受性和抗性信息，以及一大组多年生植物碎米荠野外受损情况的信息。通过在一个共同花园实验中对植物进行幼虫食草和修剪的组合处理来估计植物的耐受性。我们没有发现幼虫取食造成的损害与修剪造成的损害比例会影响植物反应的证据。损害处理对三个测量的适合度成分有负面影响，并且还导致攻击后一年开花提前。耐受性与起源种群的攻击强度相关，即来自攻击强度较高种群的植物在受损后的年份更有可能开花。然而，我们没有发现耐受性与抗性之间存在关联的证据。这些结果表明，食草动物驱动了耐受性增加的进化，并且耐受性的变化与抗性的变化没有联系。我们建议，同时研究耐受性、田间攻击强度和抗性构成了一种强大的工具，有助于理解植物避免食草动物损害负面影响策略的进化方式。
