Cespedes Ann, Penz Carla M, DeVries Philip J
Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, 70148, USA.
J Anim Ecol. 2015 May;84(3):808-816. doi: 10.1111/1365-2656.12325. Epub 2015 Jan 7.
Flight is a key innovation in the evolutionary success of insects and essential to dispersal, territoriality, courtship and oviposition. Wing shape influences flight performance and selection likely acts to maximize performance for conducting essential behaviours that in turn results in the evolution of wing shape. As wing shape also contributes to fitness, optimal shapes for particular flight behaviours can be assessed with aerodynamic predictions and placed in an ecomorphological context. Butterflies in the tribe Haeterini (Nymphalidae) are conspicuous members of understorey faunas in lowland Neotropical forests. Field observations indicate that the five genera in this clade differ in flight height and behaviour: four use gliding flight at the forest floor level, and one utilizes flapping flight above the forest floor. Nonetheless, the association of ground level gliding flight behaviour and wing shape has never been investigated in this or any other butterfly group. We used landmark-based geometric morphometrics to test whether wing shapes in Haeterini and their close relatives reflected observed flight behaviours. Four genera of Haeterini and some distantly related Satyrinae showed significant correspondence between wing shape and theoretical expectations in performance trade-offs that we attribute to selection for gliding in ground effect. Forewing shape differed between sexes for all taxa, and male wing shapes were aerodynamically more efficient for gliding flight than corresponding females. This suggests selection acts differentially on male and female wing shapes, reinforcing the idea that sex-specific flight behaviours contribute to the evolution of sexual dimorphism. Our study indicates that wing shapes in Haeterini butterflies evolved in response to habitat-specific flight behaviours, namely gliding in ground effect along the forest floor, resulting in ecomorphological partitions of taxa in morphospace. The convergent flight behaviour and wing morphology between tribes of Satyrinae suggest that the flight environment may offset phylogenetic constraints. Overall, this study provides a basis for exploring similar patterns of wing shape evolution in other taxa that glide in ground effect.
飞行是昆虫进化成功的一项关键创新,对于扩散、领地行为、求偶和产卵至关重要。翅膀形状会影响飞行性能,而自然选择可能会促使翅膀形状朝着能最大化执行基本行为的性能方向演化,进而导致翅膀形状的进化。由于翅膀形状也与适应性有关,因此可以通过空气动力学预测来评估特定飞行行为的最佳形状,并将其置于生态形态学背景中。Haeterini族(蛱蝶科)的蝴蝶是新热带低地森林林下动物群中引人注目的成员。野外观察表明,这个进化枝中的五个属在飞行高度和行为上存在差异:四个属在森林地面水平使用滑翔飞行,另一个属在森林地面上方使用扑翼飞行。然而,在这个或任何其他蝴蝶类群中,从未研究过地面水平滑翔飞行行为与翅膀形状之间的关联。我们使用基于地标点的几何形态测量学来测试Haeterini族及其近缘种的翅膀形状是否反映了观察到的飞行行为。Haeterini族的四个属和一些亲缘关系较远的眼蝶亚科在翅膀形状与我们归因于地面效应滑翔选择的性能权衡理论预期之间表现出显著的对应关系。所有分类单元的前翅形状在性别之间存在差异,并且雄性翅膀形状在滑翔飞行方面的空气动力学效率比相应的雌性更高。这表明自然选择对雄性和雌性翅膀形状的作用不同,强化了特定性别的飞行行为有助于性二态性进化的观点。我们的研究表明,Haeterini族蝴蝶的翅膀形状是为了适应特定栖息地的飞行行为而进化的,即沿着森林地面在地面效应中滑翔,从而在形态空间中形成了分类单元的生态形态分区。眼蝶亚科各部落之间趋同的飞行行为和翅膀形态表明,飞行环境可能会抵消系统发育限制。总体而言,本研究为探索其他在地面效应中滑翔的分类单元中类似的翅膀形状进化模式提供了基础。