Department of Zoology, Oregon State University, Corvallis, OR 97331, USA.
Evolution. 2010 Sep;64(9):2614-28. doi: 10.1111/j.1558-5646.2010.01027.x.
For many marine fish, intense larval mortality may provide considerable opportunity for selection, yet much less is known about the evolutionary potential of larval traits. We combined field demographic studies and manipulative experiments to estimate quantitative genetic parameters for both larval size and swimming performance for a natural population of a common coral-reef fish, the bicolor damselfish (Stegastes partitus). We also examined selection on larval size by synthesizing information from published estimates of selective mortality. We introduce a method that uses the Lande-Arnold framework for examining selection on quantitative traits to empirically reconstruct adaptive landscapes. This method allows the relationship between phenotypic value and fitness components to be described across a broad range of trait values. Our results suggested that despite strong viability selection for large larvae and moderate heritability (h(2) = 0.29), evolutionary responses of larvae would likely be balanced by reproductive selection favoring mothers that produce more, smaller offspring. Although long-term evolutionary responses of larval traits may be constrained by size-number trade-offs, our results suggest that phenotypic variation in larval size may be an ecologically important source of variability in population dynamics through effects on larval survival and recruitment to benthic populations.
对于许多海洋鱼类来说，强烈的幼鱼死亡率可能为选择提供了相当大的机会，但对于幼鱼特征的进化潜力却知之甚少。我们结合野外人口研究和操纵实验，估计了一种常见珊瑚礁鱼——双色雀鲷（Stegastes partitus）自然种群的幼鱼大小和游泳性能的数量遗传参数。我们还通过综合已发表的选择性死亡率估计值的信息，研究了幼鱼大小的选择。我们引入了一种方法，该方法使用 Lande-Arnold 框架来检验数量性状的选择，以经验性地重建适应性景观。该方法允许在广泛的性状值范围内描述表型值与适合度分量之间的关系。我们的研究结果表明，尽管大型幼虫的生存力选择很强，且遗传力适中（h(2) = 0.29），但生殖选择有利于生育更多、更小后代的母亲，这可能会平衡幼虫的进化反应。尽管幼鱼特征的长期进化反应可能受到大小-数量权衡的限制，但我们的研究结果表明，幼鱼大小的表型变异可能是通过对幼鱼存活率和底栖种群补充的影响，成为种群动态中具有生态重要性的可变性来源。
