Assessing adaptive phenotypic plasticity by means of conditional strategies from empirical data: the Latent Environmental Threshold Model

Conditional strategies are the most common form of discrete phenotypic plasticity. In a conditional strategy, the phenotype expressed by an organism is determined by the difference between an environmental cue and a threshold, both of which may vary among individuals. The Environmental Threshold model (ETM) has been proposed as a mean to understand the evolution of conditional strategies, but has been surprisingly seldom applied to empirical studies. A hindrance for the application of the ETM is that often, the proximate cue triggering the phenotypic expression and the individual threshold are not measurable, and can only be assessed using a related observable cue. We describe a new statistical model that can be applied in this common situation. The Latent Environmental Threshold Model (LETM) allows for a measurement error in the phenotypic expression of the individual environmental cue and a purely genetically determined threshold. We show that coupling our model with quantitative gene...

条件策略（conditional strategy）是离散表型可塑性（discrete phenotypic plasticity）最常见的表现形式。在条件策略下，生物体所表达的表型由环境线索与阈值之间的差值决定，且二者均可因个体差异而有所不同。环境阈值模型（Environmental Threshold Model, ETM）最初被提出用于阐释条件策略的演化过程，但令人意外的是，其在实证研究中的应用却极为罕见。阻碍该模型应用的一大核心障碍在于：触发表型表达的近因线索以及个体阈值通常无法直接被观测，仅能通过相关的可观测线索进行间接评估。为此，我们提出了一种可适配该常见研究场景的新型统计模型。潜在环境阈值模型（Latent Environmental Threshold Model, LETM）可允许个体环境线索的表型表达存在测量误差，且阈值由遗传因素完全决定。我们证实，将本模型与数量基因相关研究相结合……