Am Nat. 2020 Nov;196(5):609-619. doi: 10.1086/710708. Epub 2020 Sep 22.
AbstractEarly-life conditions may have long-lasting effects on life history. In color polymorphic species, morph-specific sensitivity to environmental conditions may lead to differential fitness. In tawny owls (), pheomelanin-based color polymorphism is expected to be maintained because the brown morph has higher adult fitness in warmer environments, while selection favors the gray morph under colder conditions. Here we investigate body mass at fledging and its consequences until adulthood in a population at the species' cold range margin. Using 40 years of data (1979-2017), we show that brown pairs, which mainly produce brown offspring consistent with a one-locus-two-alleles inheritance model, consistently raised heavier offspring than mixed (gray-brown) pairs and gray pairs. Offspring mass declined seasonally, except among offspring raised by brown pairs. Brown offspring could be heavier because of morph-specific parental care and/or offspring growth. Furthermore, mass at fledging is associated with fitness: the probability of local recruitment into the breeding population increased with higher mass at fledging, especially in mild winters and with favorable food conditions, although recruitment is not morph specific. Fledgling mass thus provides a fitness benefit in terms of recruitment probability that is modulated by environmental factors, which appear to level off any direct morph-specific recruitment benefits.
摘要 早期生活条件可能对生命史产生持久影响。在颜色多态物种中，形态特异性对环境条件的敏感性可能导致不同的适合度。在茶隼（）中，预计基于黑色素的颜色多态性将得以维持，因为棕色形态在温暖的环境中具有更高的成年适合度，而在寒冷的条件下，选择有利于灰色形态。在这里，我们研究了处于物种冷区边缘的一个种群在离巢时的体重及其成年后的后果。利用 40 年的数据（1979-2017 年），我们表明，主要产生与单基因座双等位基因遗传模型一致的棕色后代的棕色对，始终比混合（灰-棕色）对和灰色对养育出更重的后代。除了由棕色对养育的后代外，后代的体重随季节下降。棕色后代可能更重，因为形态特异性的亲代照顾和/或后代的生长。此外，离巢时的体重与适合度相关：在当地重新招募到繁殖种群的概率随着离巢时体重的增加而增加，特别是在温和的冬季和有利的食物条件下，尽管招募与形态无关。因此，在招募概率方面，离巢时的体重为繁殖提供了一种适合度优势，这种优势受到环境因素的调节，这些因素似乎抵消了任何直接的形态特异性招募优势。
