Department of Biology, Wake Forest University, Winston-Salem, NC, USA.
J Anim Ecol. 2018 Jul;87(4):1149-1159. doi: 10.1111/1365-2656.12824. Epub 2018 Apr 11.
Integrated visual displays that combine gesture with colour are nearly ubiquitous in the animal world, where they are shaped by sexual selection for their role in courtship and competition. However, few studies assess how multiple selection regimens operate on different components of these complex phenotypes on a macroevolutionary scale. Here, we study this issue by assessing how both sexual and ecological selection work together to influence visual display complexity in the birds of paradise. We first find that sexual dichromatism is highest in lekking species, which undergo more intense sexual selection by female choice, than non-lekking species. At the same time, species in which males directly compete with one another at communal display courts have more carotenoid-based ornaments and fewer melanin ornaments. Meanwhile, display habitat influences gestural complexity. Species that dance in the cluttered understorey have more complex dances than canopy-displaying species. Taken together, our results illustrate how distinct selection regimens each operate on individual elements comprising a complex display. This supports a modular model of display evolution, wherein the ultimate integrated display is the product of synergy between multiple factors that select for different types of phenotypic complexity.
综合视觉显示器，将手势与颜色结合，在动物世界中几乎无处不在，它们是通过性选择形成的，因为它们在求偶和竞争中发挥作用。然而，很少有研究评估多种选择方案如何在宏观进化尺度上对这些复杂表型的不同成分起作用。在这里，我们通过评估性选择和生态选择如何共同影响天堂鸟的视觉展示复杂性来研究这个问题。我们首先发现，性二色性在通过雌性选择经历更强烈性选择的领地性物种中最高，而不是非领地性物种。同时，在共同展示法庭上雄性之间直接竞争的物种具有更多基于类胡萝卜素的装饰物和更少的黑色素装饰物。同时，展示栖息地影响手势的复杂性。在杂乱的林下跳舞的物种比在树冠展示物种的舞蹈更复杂。总的来说，我们的结果说明了不同的选择方案如何分别作用于构成复杂展示的各个元素。这支持了展示进化的模块化模型，其中最终的综合展示是多种选择不同类型表型复杂性的因素之间协同作用的产物。
