Rate and capacity of acclimation of temperature tolerance in ectothermic animals

Organisms experience environments that change by different amounts and at
different rates throughout their lives. Phenotypic plasticity helps
organisms respond to such change because it can facilitate a ‘match’
between the phenotype of the individual and the phenotype that is optimal
in its present environment. Here we evaluate the ability of organisms to
match both the amplitude and tempo of environmental fluctuations by asking
whether a relationship exists between the capacity and rate of phenotypic
plasticity, and if so, in what direction? We re-analyze published data
from experiments documenting the temporal dynamics of acclimation in
thermal tolerance to temperature change. Across species of reptiles,
amphibians, fish, insects and crustaceans, we find that the rate and the
capacity with which thermal tolerance can respond plastically to
temperature change is negatively correlated. In other words, when plastic
adjustment of the phenotype is large, the rate at which that adjustment
can be realized is slow.. Our results indicate that if changes in the
environment occur rapidly and are large in magnitude, an example being the
extremes in weather brought about by climate change, it may be difficult
for organisms to evolve plasticity that is rapid enough and of sufficient
capacity to counteract them.

生物体在其生命周期内，所遭遇的环境变化幅度与速率均存在差异。表型可塑性（phenotypic plasticity）可帮助生物体应对此类环境变化，因其能够促使个体表型与当前环境下的最优表型达成匹配。本研究通过探究表型可塑性的容量与速率之间是否存在关联，若存在则明确其方向，以此评估生物体匹配环境波动幅度与速率的能力。我们重新分析了已发表的、记录温度变化诱导的热耐受性驯化（acclimation）时间动态的实验数据。针对爬行动物、两栖动物、鱼类、昆虫及甲壳动物多个物种类群，我们发现：生物体热耐受性对温度变化的塑性响应速率与容量呈负相关关系。换言之，当个体表型的塑性调整幅度较大时，该调整的实现速率往往较慢。我们的研究结果表明，若环境变化发生迅速且幅度显著——例如气候变化引发的极端天气事件——生物体或许难以演化出足够快速且容量充足的可塑性机制，以抵消此类环境变化带来的影响。