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.

物种的出现格局部分受其对生境条件的亲和性所塑造。对于有翅生物而言，与飞行相关的性状是其生态表现的核心决定因素。然而，由于两性生殖角色存在差异，我们推测二者的飞行能量预算会出现分化，进而导致两性间的选择响应各不相同。本研究以热带食果蝴蝶为模式类群，探究飞行形态、性二型（sexual dimorphism）与垂直分层之间的协同演化关系。我们对横跨3341公顷区域内的7个采样点中的94种亚马逊食果蝴蝶开展了采样分析。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）估算物种的层位偏好。研究发现，两性的翅胸比均存在显著的系统发育信号（phylogenetic signal）；体型更粗壮、飞行速度更快的物种偏好林冠层，而体型更纤细、飞行速度较慢的物种则偏好林下层。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。在物种种内，雄性个体的体型较雌性更为粗壮，且林下栖息物种的性二型特征更为明显。由于性状-生境关联与系统发育背景相互独立，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二型对飞行生物演化及生态适应的影响。