Mikolajewski D J, Scharnweber K, Jiang B, Leicht S, Mauersberger R, Johansson F
Institut für Biologie, Freie Universität Berlin, Berlin, Germany.
Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
J Evol Biol. 2016 Jul;29(7):1394-405. doi: 10.1111/jeb.12879. Epub 2016 Apr 25.
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 intercorrelated 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 intercorrelated traits, expressing a wider abdomen, a higher abdominal muscles mass and a larger branchial chamber compared with species from dragonfly lakes. In contrast, populations within species did not show significant differences in muscle mass and branchial chamber size between lake types in three of the species. High multicollinearity 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.
爆发式逃逸速度是一种有效且广泛应用于躲避捕食者的行为，爆发式逃逸速度依赖于几种不同的形态特征。然而，我们对行为和潜在的形态属性如何随着选择性捕食方式的变化而协同变化知之甚少。我们利用白纹蜻属的幼虫，研究了体型和爆发式游泳介导形态的相互关联特征分化，以应对与栖息地转变相关的爆发式逃逸速度降低的情况。该属的物种经历了一个众所周知的栖息地转变，从有捕食性鱼类的湖泊（鱼类湖泊）转变为以大型捕食性蜻蜓为主的无捕食性鱼类的湖泊（蜻蜓湖泊），同时对逃逸爆发速度的选择压力有所放松。结果表明，与来自蜻蜓湖泊的物种相比，来自鱼类湖泊且具有更快爆发速度的物种进化出了一系列功能上相互关联的特征，表现为腹部更宽、腹部肌肉质量更高以及鳃腔更大。相比之下，在三个物种中，物种内的种群在不同湖泊类型之间的肌肉质量和鳃腔大小没有显著差异。变量之间的高多重共线性表明，当白纹蜻从鱼类湖泊转变为蜻蜓湖泊时，这些特征是协同进化而非独立进化的。因此，蜻蜓湖泊物种对爆发式逃逸速度的选择压力放松导致腹部肌肉相关减少以及鳃腔变小，这可能是为了节省产生和/或维持成本。我们的结果强调了研究综合行为和形态特征对于全面理解复杂表型进化的重要性。
