Data from: Coevolution between flight morphology, vertical stratification and sexual dimorphism: what can we learn from tropical butterflies?

Occurrence patterns are partly shaped by affinity of species with habitat conditions. For winged organisms, flight-related attributes are vital for ecological performance. However, due to the different reproductive roles of each sex, we expect divergence in flight energy budget, and consequently different selection responses between sexes. We used tropical frugivorous butterflies as models to investigate coevolution between flight morphology, sex dimorphism and vertical stratification. We studied 94 species of Amazonian fruit-feeing butterflies sampled in seven sites across 3341 ha. We used wing-thorax ratio as a proxy for flight capacity and hierarchical Bayesian modeling to estimate stratum preference. We detected a strong phylogenetic signal in wing-thorax ratio in both sexes, and stouter fast-flying species preferred the canopy while slenderer slow-flying species preferred the understorey. However, this relationship was stronger in females than in males, suggesting that female phenotype associates more intimately with habitat conditions. Within species, males were stouter than females and sexual dimorphism was sharper in understorey species. Because trait-habitat relationships were independent from phylogeny, the matching between flight morphology and stratum preference is more likely to reflect adaptive radiation than shared ancestry. This study sheds light on the impact of flight and sexual dimorphism on the evolution and ecological adaptation of flying organisms.

物种的出现格局在一定程度上由其与生境条件的亲和性所塑造。对于具翅生物而言，与飞行相关的性状对其生态表现至关重要。然而，由于两性间繁殖角色存在差异，我们推测其飞行能量预算会出现分化，进而导致两性间的选择响应有所不同。本研究以热带食果蝴蝶（frugivorous butterflies）为模式类群，探究飞行形态、性别二态性（sexual dimorphism）与垂直分层（vertical stratification）之间的协同演化（coevolution）关系。我们对亚马逊流域3341公顷范围内7个采样点的94种食果蝴蝶进行了采样分析。以翅胸比（wing-thorax ratio）作为飞行能力的替代指标，并采用分层贝叶斯模型（hierarchical Bayesian modeling）估算其层位偏好。研究发现，两性的翅胸比均存在显著的系统发育信号（phylogenetic signal）；体型粗壮、飞行速度较快的物种偏好冠层（canopy），而体型纤细、飞行速度较慢的物种则偏好林下层（understorey）。不过，这一关联在雌性个体中表现得更为显著，表明雌性的表型与生境条件的关联更为紧密。在物种内部，雄性个体的体型较雌性更为粗壮，且林下层物种的性别二态性更为显著。由于性状与生境的关联不受系统发育背景的影响，飞行形态与层位偏好之间的匹配更可能反映适应性辐射（adaptive radiation），而非共同祖先的遗传特征。本研究揭示了飞行能力与性别二态性对具翅生物演化与生态适应的影响。