Mikolajewski Dirk Johannes, Johansson Frank, Wohlfahrt Bianca, Stoks Robby
Laboratory for Aquatic Ecology, Katholieke Universiteit Leuven, Charles de Bériotstraat 32, B-3000 Leuven, Belgium.
Evolution. 2006 Jun;60(6):1306-10.
Antagonistic selection by different predators has been suggested to underlie variation in morphological antipredator traits among and within species. Direct empirical proof is equivocal, however, given the potential interrelationships of morphological and behavioral traits. Here, we tested whether spines in larvae of the dragonfly Leucorrhinia caudalis, which are selected for by fish predators, are selected against by invertebrate aeshnid predators. Using a manipulative approach by cutting spines instead of making comparisons among species or inducing spines, we were able to decouple the presence of spines from other potentially covarying morphological antipredator traits. Results showed survival selection for the loss of spines imposed by invertebrate predation. Moreover, spined and nonspined larval L. caudalis did not differ in the key antipredator behaviors, activity level, and escape burst swimming speed. The observed higher mortality of spined larvae can therefore be directly linked to selection by aeshnid predation against spines.
不同捕食者的拮抗选择被认为是物种间和物种内形态抗捕食性状变异的基础。然而，鉴于形态和行为性状之间的潜在相互关系，直接的实证证据并不明确。在这里，我们测试了蜻蜓Leucorrhinia caudalis幼虫的刺，这些刺是被鱼类捕食者选择的，是否会被无脊椎动物豆娘捕食者所排斥。通过采用切割刺的操作方法，而不是在物种间进行比较或诱导刺的产生，我们能够将刺的存在与其他潜在相关的形态抗捕食性状分离开来。结果表明，无脊椎动物捕食导致的刺的丧失存在生存选择。此外，有刺和无刺的Leucorrhinia caudalis幼虫在关键的抗捕食行为、活动水平和逃避爆发游泳速度方面没有差异。因此，观察到的有刺幼虫较高的死亡率可以直接与豆娘捕食对刺的选择联系起来。
