Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA.
Am Nat. 2013 Sep;182(3):313-27. doi: 10.1086/671161. Epub 2013 Jul 15.
In many species, nongenetic phenotypic variation helps mitigate risk associated with an uncertain environment. In some cases, developmental cues can be used to match phenotype to environment-a strategy known as predictive plasticity. When environmental conditions are entirely unpredictable, generating random phenotypic diversity may improve the long-term success of a lineage-a strategy known as diversified bet hedging. When partially reliable information is available, a well-adapted developmental strategy may strike a balance between the two strategies. We use information theory to analyze a model of development in an uncertain environment, where cue reliability is affected by variation both within and between generations. We show that within-generation variation in cues decreases the reliability of cues without affecting their fitness value. This transpires because the optimal balance of predictive plasticity and diversified bet hedging is unchanged. However, within-generation variation in cues does change the developmental mechanisms used to create that balance: developmental sensitivity to such cues not only helps match phenotype to environment but also creates phenotypic diversity that may be useful for hedging bets against environmental change. Understanding the adaptive role of developmental sensitivity thus depends on a proper assessment of both the predictive power and the structure of variation in environmental cues.
在许多物种中，非遗传表型变异有助于减轻与不确定环境相关的风险。在某些情况下，可以利用发育线索将表型与环境相匹配——这种策略被称为预测性可塑性。当环境条件完全不可预测时，产生随机表型多样性可能会提高谱系的长期成功——这种策略被称为多样化的风险对冲。当有部分可靠信息可用时，一个适应性良好的发育策略可能会在这两种策略之间取得平衡。我们使用信息论来分析不确定环境中的发育模型，其中线索的可靠性受到代内和代际变异的影响。我们表明，线索的代内变异会降低线索的可靠性而不影响其适应值。这是因为预测性可塑性和多样化风险对冲之间的最佳平衡保持不变。然而，线索的代内变异确实改变了用于创造这种平衡的发育机制：对这些线索的发育敏感性不仅有助于将表型与环境相匹配，而且还创造了可能有助于对冲环境变化的表型多样性。因此，理解发育敏感性的适应作用取决于对环境线索的预测能力和变异结构的适当评估。
