Poláček Miroslav, Griggio Matteo, Mikšík Ivan, Bartíková Michaela, Eckenfellner Manfred, Hoi Herbert
Institute of Zoology Slovak Academy of Sciences Bratislava Slovakia; Department of Integrative Biology and Evolution Konrad Lorenz Institute of Ethology University of Veterinary Medicine, Vienna Vienna Austria.
Department of Integrative Biology and Evolution Konrad Lorenz Institute of Ethology University of Veterinary Medicine, Vienna Vienna Austria; Department of Biology University of Padova Padova Italy.
Ecol Evol. 2017 Jan 14;7(3):941-949. doi: 10.1002/ece3.2664. eCollection 2017 Feb.
Avian eggshell color seems to fulfill multiple functions, some of them being structural and others signaling. In this study, we tested whether or not eggshell coloration may play a role in sexual selection of Tree Sparrows (). According to the "Sexually selected eggshell coloration" hypothesis, eggshell coloration signals female, egg or chick quality and males adjust parental investment according to this signal. Eggs of this species are covered with brown spots and patches, and variation between clutches is high. We found that eggshell coloration correlates with both protoporphyrin and biliverdin, but protoporphyrin concentrations are ten times higher. Eggshell coloration reflects egg and offspring quality, but not female quality. Thus, eggshell coloration may signal female postmating investment in offspring rather than female quality. Furthermore, differential allocation in terms of maternal investment is supported by the fact that females lay more pigmented clutches when mated to males with bigger melanin-based ornaments relative to their own. Moreover, males invested proportionally more to chicks that hatched from more pigmented clutches. Our correlative results thus seem to support a role of sexual selection in the evolution of eggshell coloration in birds laying brown eggs, pigmented mainly by protoporphyrin.
鸟类蛋壳颜色似乎具有多种功能，其中一些是结构性的，另一些则具有信号作用。在本研究中，我们测试了蛋壳颜色是否可能在树麻雀（ ）的性选择中发挥作用。根据“性选择的蛋壳颜色”假说，蛋壳颜色可表明雌性、卵或雏鸟的质量，雄性会根据这一信号调整亲代投资。该物种的卵上布满褐色斑点和斑块，不同窝卵之间的差异很大。我们发现蛋壳颜色与原卟啉和胆绿素均相关，但原卟啉浓度要高十倍。蛋壳颜色反映了卵和后代的质量，但不能反映雌性的质量。因此，蛋壳颜色可能表明雌性在交配后对后代的投资，而非雌性的质量。此外，雌性与具有比自身更大的基于黑色素的饰羽的雄性交配时会产下颜色更深的窝卵，这一事实支持了亲代投资方面的差异分配。而且，雄性对从颜色更深的窝卵中孵出的雏鸟投入比例更高。因此，我们的相关性结果似乎支持了性选择在主要由原卟啉着色的褐色卵鸟类蛋壳颜色进化中所起的作用。
