Data from: Changing the habitat: the evolution of inter-correlated traits to escape from predators

Burst escape speed is an effective and widely used behaviour for evading predators, with burst escape speed relying on several different morphological features. However, we know little about how behavioural and underlying morphological attributes change in concert as a response to changes in selective predation regime. We studied inter-correlated trait differentiation of body shape and burst-swim-mediating morphology in response to a habitat shift related reduction in burst escape speed using larvae of the dragonfly genus Leucorrhinia. Species in this genus underwent a well-known habitat shift from predatory fish lakes (fish-lakes) to predatory fish free lakes dominated by large predatory dragonflies (dragonfly-lakes) accompanied by relaxed selection on escape burst speed. Results revealed that species from fish-lakes that possess faster burst speed have evolved a suite of functionally inter-correlated traits, expressing a wider abdomen, a higher abdominal muscles mass and a larger branchial chamber compared to species from dragonfly-lakes. In contrast, populations within species did not show significant differences in muscle mass and branchial chamber size between lakes types in three of the species. High multi-collinearity among variables suggests that traits have evolved in concert rather than independently when Leucorrhinia shifted from fish lakes to dragonfly lakes. Thus, relaxed selection on burst escape speed in dragonfly-lake species resulted in a correlated reduction of abdominal muscles and a smaller branchial chamber, likely to save production and/or maintenance costs. Our results highlight the importance of studying integrated behavioural and morphological traits to fully understand the evolution of complex phenotypes.爆发逃逸速度（burst escape speed）是一种高效且被广泛应用的避敌行为，其表达依赖于多种不同的形态特征。然而，目前学界对行为特征与潜在形态属性如何协同响应捕食选择压力格局的变化仍知之甚少。为探究栖息地转变引发的爆发逃逸速度降低所带来的行为与形态协同变化，本研究以蜻蜓属（Leucorrhinia）幼虫为实验材料，分析了体型与介导爆发游泳的形态特征之间的互相关联性状分化。该属物种经历了一次公认的栖息地转变：从掠食性鱼类湖泊（fish-lakes，简称鱼湖）转变为以大型掠食性蜻蜓为优势捕食者的无鱼湖泊（dragonfly-lakes，简称蜻蜓湖），此过程伴随爆发逃逸速度选择压力的松弛。研究结果显示，与蜻蜓湖物种相比，来自鱼湖且爆发逃逸速度更快的物种演化出了一系列功能上相互关联的性状：腹部更宽阔、腹部肌肉质量更高、鳃室（branchial chamber）更大。与之相对，在其中三个物种中，同一物种内的不同种群在两种湖泊生境下的肌肉质量与鳃室大小均未表现出显著差异。变量间存在高度多重共线性（multi-collinearity），这表明当蜻蜓属物种从鱼湖向蜻蜓湖转变时，其性状是协同演化而非独立演化的。因此，蜻蜓湖物种所经历的爆发逃逸速度选择压力松弛，导致其腹部肌肉与鳃室发生协同性缩减，这大概率是为了节省性状生产与/或维持成本。本研究结果凸显了整合行为与形态特征研究的重要性，这有助于全面理解复杂表型的演化机制。