the Department of Biology, University of Rochester, RC Box 270211, Rochester, NY 14627. Richard Glor is now at the Biodiversity Institute and Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS.
J Hered. 2013 Nov-Dec;104(6):862-73. doi: 10.1093/jhered/est060. Epub 2013 Sep 27.
The diversity of sexual signals is astounding, and divergence in these traits is believed to be associated with the early stages of speciation. An increasing number of studies also suggest a role for natural selection in driving signal divergence for effective transmission in heterogeneous environments. Both speciation and adaptive divergence, however, are contingent on the sexual signal being heritable, yet this often remains assumed and untested. It is particularly critical that the heritability of carotenoid-based sexual signals is investigated because such traits may instead be phenotypically plastic indicators of an individual's quality that exhibit no or little heritable variation. We present the first study to investigate the relative contribution of genetic and environmental factors to the striking diversity of dewlap color and pattern in Anolis lizards. Using a breeding experiment with Anolis distichus populations exhibiting different dewlap phenotypes, we raise F1 offspring in a common garden experiment to assess whether dewlap color is inherited. We follow this with carotenoid supplementation to investigate the influence of dietary pigments to dewlap color variation. We find significant differences in several aspects of dewlap color and pattern to persist to the F1 generation (fathers: N = 19; F1 males: N = 50; P < 0.01) with no change in dewlap phenotype with carotenoid supplementation (N = 52; P > 0.05). These results strongly support that genetic differences underlie dewlap color variation, thereby satisfying a key requirement of natural selection. Our findings provide an important stepping-stone to understanding the evolution of an incredibly diverse signal important for sexual selection and species recognition.
性信号的多样性令人惊讶，这些特征的分歧被认为与物种形成的早期阶段有关。越来越多的研究还表明，自然选择在驱动信号分歧方面发挥了作用，以在异质环境中实现有效传播。然而，无论是物种形成还是适应性分歧，都取决于性信号的可遗传性，但这往往仍然是假设的，未经检验的。特别重要的是，要研究基于类胡萝卜素的性信号的遗传性，因为这些特征可能是个体质量的表型可塑性指标，没有或几乎没有可遗传的变化。我们提出了第一项研究，以调查遗传和环境因素对安乐蜥（Anolis lizards）颈垂颜色和图案惊人多样性的相对贡献。我们利用具有不同颈垂表型的安乐蜥种群进行繁殖实验，在共同的园林实验中饲养 F1 后代，以评估颈垂颜色是否可遗传。随后，我们进行类胡萝卜素补充实验，以研究饮食色素对颈垂颜色变化的影响。我们发现颈垂颜色和图案的几个方面在 F1 代中仍存在显著差异（父亲：N = 19；F1 雄性：N = 50；P < 0.01），而类胡萝卜素补充并没有改变颈垂表型（N = 52；P > 0.05）。这些结果强烈支持遗传差异是颈垂颜色变化的基础，从而满足了自然选择的一个关键要求。我们的发现为理解对性选择和物种识别至关重要的极其多样化信号的进化提供了重要的基石。
