THE EVOLUTION OF DISPERSAL IN SPATIALLY AND TEMPORALLY VARYING ENVIRONMENTS
THE EVOLUTION OF DISPERSAL IN SPATIALLY AND TEMPORALLY VARYING ENVIRONMENTS
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DOI：
10.1086/285453
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发表时间：
1992-12-01
影响因子：
2.9
通讯作者：
HOLT, RD
中科院分区：
文献类型：
--
作者：
MCPEEK, MA;HOLT, RD
使用一个简单的两补丁模型，我们研究如何在空间和时间上的变化模式的承载能力影响自然选择的扩散。在每个补丁的人口规模分别调节，根据离散代逻辑方程，和个人分散从每个补丁的倾向，由他们的基因型。我们认为基因型，表达相同的分散倾向，在两个补丁和基因型，表达补丁特定的分散倾向。与以前的分析相反，我们的研究结果表明，在几乎所有的生境变异制度，包括空间变化和时间恒定的环境下，一定程度的扩散是有利的选择。此外，在不同的条件下，两种非常不同的多态性是有利的。当承载能力在空间上而不是时间上变化时，任何数量的基因型与斑块特异性扩散倾向的比例成反比的承载能力的比率可以共存。这一结果扩展了以前的分析表明，分散是有利的，在这样的环境中，如果个人可以改变分散的倾向，以响应环境的线索。相反，当承载能力在空间和时间上都不同，但在均值或方差不同，只有两种基因型（高扩散和无扩散基因型）的多态性是有利的，当唯一可能的基因型是表达相同的扩散倾向，在两个补丁。然而，这种二态性可以被入侵，并取代一个基因型与特定的组合的补丁特定的扩散倾向的比例也成反比的比例的平均人口规模。我们讨论了一些可检验的预测，该模型表明，预计在种群内和种群之间的扩散性状的表型和遗传变异的数量，以及在何种程度上影响扩散倾向的表型性状的表达应该是敏感的环境条件。该模型还提出了竞争物种在不同环境中共存的新机制。
Using a simple two-patch model, we examine how patterns of spatial and temporal variation in carrying capacities affect natural selection on dispersal. The size of the population in each patch is regulated separately, according to a discrete-generation logistic equation, and individuals disperse from each patch at propensities determined by their genotype. We consider genotypes that express the same dispersal propensities in both patches and genotypes that express patch-specific disperal propensities. Contrary to previous analyses, our results show that some level of dispersal is favored by selection under almost all regimes of habitat variability, including a spatially varying and temporally constant environment. Furthermore, two very different polymorphisms are favored under different conditions. When carrying capacities vary spatially but not temporally, any number of genotypes with patch-specific dispersal propensities in ratios inversely proportional to the ratio of the carrying capacities can coexist. This result extends previous analyses to show that dispersal is favored in such an environment if individuals can alter dispersal propensities in response to environmental cues. In contrast, when carrying capacities vary both spatially and temporally but differ in mean or variance, a polymorphism of only two genotypes (a high-dispersal and a no-dispersal genotype) is favored when the only genotypes possible are ones expressing the same dispersal propensity in both patches. However, this dimorphism can be invaded and replaced by one genotype with a particular combination of patch-specific dispersal propensities in a ratio also inversely proportional to the ratio of the average population sizes. We discuss a number of testable predictions this model suggests about the amounts of phenotypic and genetic variation in dispersal characters that are expected both within and between populations, and the degree to which the expression of phenotypic characters affecting dispersal propensity should be sensitive to environmental conditions. The model also suggests novel mechanisms for coexistence between competing species in varying environment.