Across latitudinal clines, the juvenile developmental rates of ectotherms often covary with the length of the growing season, due to life-history trade-offs imposed by the time-constrained environments. However, as the start of the growing season often varies substantially across years, adaptive parental effects on juvenile developmental rates may mediate the costs of a delayed season. By employing a meta-analysis, we tested whether larval developmental rates across a latitudinal cline of the common frog (Rana temporaria) are affected by fluctuating onsets of breeding, across years. We predicted that larval developmental rate will be inversely related to the onset of breeding, and that northern populations will be more prone to shorten their developmental rate in response to late breeding, as the costs of delayed metamorphosis should be highest in areas with a shorter growing season. We found that the larval period of both northern and southern populations responded to parental environmental conditions to a similar degree in absolute terms, but in different directions. In northern populations, a late season start correlated with decreased development time, suggesting that the evolution of parental effects aids population persistence in time-constrained environments. In southern populations, late season start correlated with increased development time, which could potentially be explained as a predator avoidance strategy. Our findings suggest that local ecological variables can induce adaptive parental effects, but responses are complex, and likely trade-off with other ecological factors.

中文翻译：

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亲代效应影响普通青蛙种群的生活史特征和环境谱系的共变异。

在不同纬度地区，由于受时间限制的环境所强加的生活史权衡，变温动物的幼年发育速率通常随生长季节的长度而变化。然而，由于生长季节的开始时间往往在不同年份有很大差异，亲本对幼体发育速度的适应性影响可能会调节生长季节延迟的成本。通过荟萃分析，我们测试了普通青蛙（Rana temporaria）在纬度上的幼虫发育率是否受到多年来繁殖开始波动的影响。我们预测，幼虫发育速度将与繁殖开始时间成反比，并且北方种群更容易因繁殖后期而缩短其发育速度，因为在生长较短的地区，延迟变态的成本应该最高。季节。我们发现，北部和南部种群的幼虫期对亲代环境条件的反应绝对程度相似，但方向不同。在北方种群中，季节开始较晚与发育时间缩短相关，这表明亲本效应的演变有助于种群在时间有限的环境中的持久存在。在南方种群中，季节开始较晚与发育时间增加相关，这可能可以解释为躲避捕食者的策略。我们的研究结果表明，当地生态变量可以引起适应性亲代效应，但反应很复杂，并且可能与其他生态因素进行权衡。