Dynamic models allowing for flexibility in complex life histories accurately predict timing of metamorphosis and antipredator strategies of prey
Dynamic models allowing for flexibility in complex life histories accurately predict timing of metamorphosis and antipredator strategies of prey
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DOI：
10.1111/j.1365-2435.2009.01598.x
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发表时间：
2009-12-01
影响因子：
5.2
通讯作者：
Ruxton, Graeme D.
中科院分区：
文献类型：
--
作者：
Higginson, Andrew D.;Ruxton, Graeme D.
1.具有复杂生活周期的动物幼虫阶段的抗捕食者防御系统的发展可能会受到建立和维持这种防御系统的相关费用的影响，因为它们影响成熟或变态的时间。各种理论处理方法表明，国防投资应该随着资源可获得性的增加而增加或减少，但最近的一个模型预测，在中等资源水平和捕食者密度时，防御投资应该最高。以前的国防投资和转型时机模型与经验数据不太吻合。在这里，我们开发了行为和形态防御投资的动态状态依赖模型，该模型使我们能够灵活地投资于防御而不是发展、变态的时间和变态时有机体的大小，这些在以前的理论中是不存在的。我们表明，这种灵活性的纳入导致了与以前使用的固定投资方法不同的预测，特别是当我们允许组织在最佳时间和状态发生蜕变时。在这些更灵活的条件下，我们预测形态防御应该对资源水平不敏感，而行为防御应该随着资源的增加而增加或减少，这取决于被捕食的风险和大体型变态时适合度的大小。我们的工作提供了一个正式的框架，在其中我们可能会在研究反捕食者防御系统的使用如何受到其成本的影响方面取得进展。我们的模型中的大多数预测都与经验结果很好地一致，并且可以根据潜在的生物学假设来理解。为什么更简单的模型无法与经验观察相匹配的原因是可以解释的，我们的预测不太匹配，有助于针对值得进一步研究的情况。
P>1. The development of antipredator defences in the larval stage of animals with complex life cycles is likely to be affected by costs associated with creating and maintaining such defences because of their impact on the timing of maturation or metamorphosis.2. Various theoretical treatments have suggested that investment in defence should both increase or decrease with increasing resource availability, but a recent model predicts investment in defences should be highest at intermediate resource level and predator density.3. Previous models of investment in defence and timing of metamorphosis provide a poor match to empirical data. Here we develop a dynamic state-dependent model of investment in behavioural and morphological defences that enables us to allow flexibility in investment in defences over development, the timing of metamorphosis and the size of the organism at metamorphosis that were absent from previous theory.4. We show that the inclusion of this flexibility results in different predictions to those of the fixed investment approach used previously, especially when we allow metamorphosis to occur at the optimal time and state for the organism.5. Under these more flexible conditions, we predict that morphological defences should be insensitive to resource level whilst behavioural defences should either increase or decrease with increasing resources depending on the predation risk and the magnitude of the fitness benefits of large size at metamorphosis.6. Our work provides a formal framework in which we might progress in the study of how the use of antipredator defences is affected by their costs. Most of the predictions of our model in are in good accord with empirical results, and can be understood in terms of the underlying biological assumptions. The reasons why simpler models failed to match empirical observations can be explained, and our predictions that are a poor match help to target the circumstances which warrant future study.