Flexible defense strategies: Competition modifies investment in behavioral vs. morphological defenses
Flexible defense strategies: Competition modifies investment in behavioral vs. morphological defenses
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DOI：
10.1890/06-1703.1
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发表时间：
2007-07-01
期刊：
影响因子：
4.8
通讯作者：
Laurila, Anssi
中科院分区：
文献类型：
--
作者：
Teplitsky, Celine;Laurila, Anssi
竞争预计会影响诱导防御的表达，但由于成本的行为和形态antipredator防御不同沿着资源梯度，其对防御的影响可能取决于所考虑的性状。我们测试了预测从不同的防御模型在蝌蚪的常见青蛙蛙temporaria，表现出两种类型的防御。在一个室外实验中，我们暴露的蝌蚪非致命的捕食者（Aeshna幼虫）和梯度的种内竞争。形态反应没有遵循任何预期的模式，因为投资在国防不受资源水平。相反，在没有捕食者的情况下，尾部深度减少。行为防御遵循状态依赖模型。总体而言，蝌蚪的防御策略揭示了一个转变，从形态和行为的防御在低蝌蚪密度的形态防御只有在高密度。这种差异可能反映了防御的不同效率。躲藏是一种有效的防御手段，但在资源稀缺的情况下是不可持续的。随着密度的增加，形态反应变得更加重要，以补偿行为冒险的增加。我们的研究结果表明，竞争可以强烈影响诱导防御的反应规范，并强调整合生态参数的重要性，影响表型可塑性的成本效益平衡。
Competition is predicted to affect the expression of inducible defenses, but because costs of behavioral and morphological antipredator defenses differ along resource gradients, its effects on defenses may depend on the traits considered. We tested the predictions from different defense models in tadpoles of the common frog Rana temporaria, which exhibit both types of defenses. In an outdoor experiment, we exposed the tadpoles to nonlethal predators (Aeshna dragonfly larvae) and to a gradient of intraspecific competition. Morphological responses did not follow any of the expected patterns, since investment in defense was not affected by resource level. Instead, tail depth decreased in the absence of predators. Behavioral defenses followed a state-dependent model. Overall, the defense strategy of the tadpoles revealed a shift from morphological and behavioral defenses at low tadpole density to morphological defense only at high density. This difference probably reflects the different efficiency of the defenses. Hiding is an effective means of defense, but it is unsustainable when resources are scarce. Morphological responses become more important with increasing density to compensate for the increase in behavioral risk-taking. Our results indicate that competition can strongly affect reaction norms of inducible defenses and highlight the importance of integrating ecological parameters that affect the cost-benefit balance of phenotypic plasticity.