Data from: Antagonistic natural and sexual selection on wing shape in a scrambling damselfly

Wings are a key trait underlying the evolutionary success of birds, bats and insects. For over a century, researchers have studied the form and function of wings to understand the determinants of flight performance. However, to understand the evolution of flight, we must comprehend not only how morphology affects performance, but how morphology and performance affects fitness. Natural and sexual selection can either reinforce or oppose each other, but their role in flight evolution remains poorly understood. Here we show that wing shape is under antagonistic selection with regard to sexual and natural selection in a scrambling damselfly. In a field setting, natural selection (survival) favored individuals with long and slender forewings and short and broad hindwings. In contrast, sexual selection (mating success) favored individuals with short and broad forewings and narrow-based hindwings. Both types of selection favored individuals of intermediate size. These results suggest that individuals face a trade-off between flight energetics and maneuverability and demonstrate how natural and sexual selection can operate in similar directions for some wing traits, i.e. wing size, but antagonistically for others, i.e. wing shape. Furthermore, they highlight the need to study flight evolution within the context of species’ mating systems and mating behaviors.

翅翼是支撑鸟类、蝙蝠与昆虫演化成功的关键性状。一个多世纪以来，研究者们始终围绕翅翼的形态与功能展开研究，以期阐明飞行性能的决定因素。然而，若要解析飞行的演化历程，我们不仅需要明晰形态如何影响飞行性能，还需掌握形态与性能如何作用于个体适合度。自然选择与性选择既可以相互强化，也可能彼此拮抗，但二者在飞行演化中所扮演的角色至今仍未得到充分阐释。本研究显示，在一种竞争型豆娘中，翅形同时受到性选择与自然选择的拮抗作用。在野外环境中，自然选择（生存选择）更青睐前翅修长纤细、后翅短宽的个体；与之相反，性选择（交配成功率选择）则更偏好前翅短宽、后翅基部狭窄的个体。两类选择均对体型中等的个体更为有利。上述结果表明，个体在飞行能量效率与飞行机动性之间存在权衡关系；同时证实了自然选择与性选择可对部分翅部性状（如翅尺寸）产生同向作用，而对另一些性状（如翅形）则产生拮抗作用。此外，本研究结果凸显了在物种交配系统与交配行为的框架下开展飞行演化研究的必要性。