van Tienderen Peter H
Netherlands Institute of Ecology, P.O. Box 40, 6666 ZG, Heteren, The Netherlands.
Evolution. 1997 Oct;51(5):1372-1380. doi: 10.1111/j.1558-5646.1997.tb01460.x.
The evolution of phenotypic plasticity is studied in a model with two reproductively isolated "species" in a coarse-grained environment, consisting of two types of habitats. A quantitative genetic model for selection was constructed, in which habitats differ in the optimal value for a focal trait, and with random dispersal among habitats. The main interest was to study the effects of different selection regimes. Three cases were investigated: (1) without any limits to plasticity; (2) without genetic variation for plasticity; and (3) with a fitness cost for phenotypically plastic reactions. In almost all cases a generalist strategy to exploit both habitats emerged. Without any limits to plasticity, optimal adaptive reactions evolved. Without any genetic variation for plasticity, a compromise strategy with an intermediate, fixed phenotype evolved, whereas in the presence of costs a plastic compromise between the demands of the habitats and the costs associated with plasticity was found. Specialization and phenotypic differentiation was only found when selection within habitats was severe and optimal phenotypes for different habitats were widely different. Under soft selection (local regulation of population numbers in each habitat) the specialists coexisted; under hard selection (global regulation of population numbers) one specialist outcompeted the other. The prevalent evolutionary outcome of compromises rather than specialization implies that costs or constraints are not necessarily detectable as local adaptation in transplantation or translocation experiments.
在一个由两种类型栖息地组成的粗粒度环境中，利用一个具有两个生殖隔离“物种”的模型研究表型可塑性的进化。构建了一个用于选择的数量遗传模型，其中栖息地在一个焦点性状的最优值上存在差异，并且个体在栖息地之间随机扩散。主要兴趣在于研究不同选择机制的影响。研究了三种情况：（1）可塑性无任何限制；（2）可塑性无遗传变异；（3）表型可塑性反应存在适合度代价。几乎在所有情况下，都会出现利用两种栖息地的通才策略。可塑性无任何限制时，会进化出最优的适应性反应。可塑性无任何遗传变异时，会进化出一种具有中间固定表型的折衷策略，而在存在代价的情况下，会发现栖息地需求与可塑性相关代价之间的可塑性折衷。只有当栖息地内的选择强烈且不同栖息地的最优表型差异很大时，才会出现特化和表型分化。在软选择（每个栖息地种群数量的局部调节）下，特化物种共存；在硬选择（种群数量的全局调节）下，一个特化物种胜过另一个。折衷而非特化成为普遍的进化结果，这意味着在移植或转移实验中，代价或限制不一定能作为局部适应性被检测到。
