Temporal environmental variation and phenotypic plasticity: a mechanism underlying priority effects
Temporal environmental variation and phenotypic plasticity: a mechanism underlying priority effects
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时间环境变化和表型可塑性：优先效应的潜在机制
DOI：
10.1111/j.2007.0030-1299.15969.x
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发表时间：
2008
期刊：
影响因子：
3.4
通讯作者：
R. Relyea
中科院分区：
文献类型：
--
作者：
J. Hoverman;R. Relyea
了解历史在群落形成中的作用一直是群落生态学的重大挑战。在这里，我们探讨了表型可塑性及其相关的性状介导的间接相互作用作为优先效应背后的机制的作用。使用具有诱导防御的生物体作为模型系统，我们研究了最初包含不同捕食者环境的水生群落如何在个体和群落水平上受到第二个捕食者的殖民化的影响。蜗牛和蝌蚪被安置在四种不同的笼养捕食者环境中（没有捕食者、鱼、小龙虾或水蝽）。然后使用致命水蝽作为捕食者，将这四个群落与三种捕食者定殖处理（无定殖、早期定殖或晚期定殖）杂交。蜗牛通过捕食者特有的行为和形态防御来应对笼中捕食者环境。在定植治疗中，具有错误表型的蜗牛试图诱导表型变化以防御新的风险。然而，最初由不同捕食者环境诱导的蜗牛通常会遭受很高的捕食率。因此，捕食风险的时间变化不仅挑战蜗牛猎物试图通过调整其防御表型来跟踪这种随时间变化的环境变化，而且还引起蜗牛和定殖捕食者之间特征介导的相互作用。对于这些群落内的蝌蚪，几乎没有证据表明蜗牛的形态反应通过寄居水蝽而间接影响蝌蚪的捕食率。出乎意料的是，在三种笼养捕食者处理中，定殖水蝽对蝌蚪的捕食率普遍较高，这表明水蝽为了应对潜在的竞争性捕食者而提高了觅食活动。总之，我们证明了一种重要的优先效应，其中一种捕食者的最初出现可以促进稍后殖民的第二种捕食者（即TMII）的捕食，这表明表型可塑性可能是优先效应背后的重要驱动因素（即历史上与捕食者的接触）。
Understanding the role of history in the formation of communities has been a major challenge in community ecology. Here, we explore the role of phenotypic plasticity and its associated trait-mediated indirect interactions as a mechanism behind priority effects. Using organisms with inducible defenses as a model system, we examine how aquatic communities initially containing different predator environments are affected at the individual and community level by the colonization of a second predator. Snails and tadpoles were established in four different caged-predator environments (no predator, fish, crayfish or water bugs). These four communities were then crossed with three predator colonization treatments (no colonization, early colonization, or late colonization) using lethal water bugs as the predator. The snails responded to the caged predator environments with predator-specific behavioral and morphological defenses. In the colonization treatments, snails possessing the wrong phenotype attempted to induce phenotypic changes to defend themselves against the new risk. However, snails initially induced by a different predator environment often suffered high predation rates. Hence, temporal variation in predation risk not only challenged the snail prey to try to track this environmental variation through time by adjusting their defensive phenotypes, but also caused trait-mediated interactions between snails and the colonizing predator. For tadpoles within these communities, there was little evidence that the morphological responses of snails indirectly effected tadpole predation rates by colonizing water bugs. Unexpectedly, predation rates on tadpoles by colonizing water bugs were generally higher in the three caged-predator treatments, suggesting that water bugs elevated their foraging activity in response to potentially competing predators. In summary, we demonstrate an important priority effect in which the initial occurrence of one species of predator can facilitate predation by a second predator that colonizes at a later date (i.e. a TMII) suggesting that phenotypic plasticity can be an important driver behind priority effects (i.e. historical exposure to predators).