Desperate larvae: influence of deferred costs and habitat requirements on habitat selection
Desperate larvae: influence of deferred costs and habitat requirements on habitat selection
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DOI：
10.3354/meps335143
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发表时间：
2007-01-01
影响因子：
2.5
通讯作者：
Marshall, Dustin J.
中科院分区：
文献类型：
--
作者：
Elkin, Che;Marshall, Dustin J.
随着海洋无脊椎动物幼虫的年龄增长，一些接受更广泛的定居线索。一个概念性的论点，绝望的幼虫假说，已被提出来解释这种行为的变化，并集中在这样的想法，幼虫应该接受不太喜欢的栖息地随着时间的推移，因为继续搜索的延迟成本太大。虽然这个模型解释了为什么一些物种随着年龄的增长而改变他们的偏好，但它很难解释其他物种没有。一般的理论考虑的问题往往集中在一个参数空间之外，这可能是典型的海洋幼虫。我们适应了一个更一般的扩散/搜索模型，专门为海洋幼虫和研究的影响，幼虫的能量摄入量，浮游动物的死亡率和栖息地的质量和丰富的利益，减少选择性在解决。我们发现，降低选择性在我们的大多数参数空间中具有自适应性优势。当浮游生物的死亡率很高时，幼虫会很快耗尽它们的资源（就像大多数卵养生物的情况一样），或者不同栖息地的质量几乎没有差异（就像通才一样）;因此，幼虫应该对定居点不那么挑剔。然而，我们的模型表明，减少选择性将不会适应幼虫可以喂养或潜在的栖息地的质量有很大的差异时。从文献中的初步迹象一般符合我们的模型的预测和发生的选择性降低可以预测的基础上生物体的栖息地特异性和能力，在兼性嗜酸性阶段的饲料。我们的模型预测，栖息地选择行为也应该在物种内有所不同。对于不进食的幼虫，较大的幼虫（即具有更多资源的幼虫）应该比较小的幼虫保持更长的选择性。对于喂养幼虫，当地的浮游生物的食物供应应强烈影响的利益，在没有解决线索延迟变态。
As marine invertebrate larvae age, some accept a wider variety of settlement cues. A conceptual argument, the desperate larva hypothesis, has been proposed to explain this change in behaviour, and focuses on the idea that larvae should accept less preferred habitats as time goes by because the deferred costs of continued searching are too great. Whilst this model has explained why some species change their preferences as they age, it struggles to account for other species that do not. General theoretical considerations of the issue have tended to focus on a parameter space outside that which is likely to be typical of marine larvae. We adapted a more general dispersal/search model specifically for marine larvae and examined the influence of larval energy intake, planktonic mortality and habitat quality and abundance on the benefits of decreased selectivity at settlement. We found that decreased selectivity carries an adaptive benefit across the majority of our parameter space. Whenever planktonic mortality is high, larvae deplete their resources quickly (as is the case for most lecithotrophs) or there is little difference in the quality of different habitats (as for generalists); therefore, larvae should become less choosy with regards to settlement. However, our model suggests that decreasing selectivity will not be adaptive when larvae can feed or when there are large differences in the quality of potential habitats. Initial indications from the literature generally conform to the predictions of our model and the occurrence of decreasing selectivity can be predicted based on an organism's habitat specificity and ability to feed during the facultative planktonic stage. Our model predicts that habitat selection behaviour should also vary within species. For non-feeding larvae, larger larvae (i.e. those with more resources) should remain selective for longer than smaller larvae. For feeding larvae, local food availability in the plankton should strongly affect the benefits of delaying metamorphosis in the absence of settlement cues.