Variation in developmental rates is not linked to environmental unpredictability in annual killifishes

Comparative evidence suggests that adaptive plasticity may evolve as a response to predictable environmental variation. However, less attention has been placed on unpredictable environmental variation, which is considered to affect evolutionary trajectories by increasing phenotypic variation (or bet-hedging). Here, we examine the occurrence of bet-hedging in egg developmental rates in seven species of annual killifish that originate from a gradient of variation in precipitation rates, under three treatment incubation temperatures (21°C, 23°C, and 25°C). In the wild, these species survive regular and seasonal habitat desiccation, as dormant eggs buried in the soil. At the onset of the rainy season embryos must be sufficiently developed in order to hatch and complete their life-cycle. We found substantial differences among species in both the mean and variation of egg development rates, as well as species-specific plastic responses to incubation temperature. Yet, there was no clear relati...

比较研究证据表明，适应性可塑性（adaptive plasticity）可作为对可预测环境变化的响应而演化。然而，针对不可预测环境变化的相关研究关注度相对不足——这类变化被认为可通过增加表型变异（又称对冲策略，bet-hedging）来影响物种的演化轨迹。本研究以7种源自降水变化梯度的一年生鳉鱼为对象，设置21℃、23℃、25℃三种孵化温度处理，探究其卵发育速率的对冲策略（bet-hedging）存在情况。在自然环境中，这些物种以埋藏于土壤中的休眠卵形式，应对周期性的季节性生境干涸；雨季来临之际，胚胎必须发育至足够成熟才能孵化并完成整个生命周期。本研究发现，不同物种的卵发育速率均值与变异程度均存在显著差异，且各物种对孵化温度的可塑性响应具有物种特异性。然而，尚未发现明确的相关关系……