Institut de Systématique, Evolution et Biodiversité, UMR 7205 CNRS/MNHN/Sorbonne Université/EPHE, Museum National d'Histoire Naturelle, Paris, France.
Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
J Evol Biol. 2021 Feb;34(2):284-295. doi: 10.1111/jeb.13726. Epub 2020 Dec 5.
Species interactions such as mimicry can promote trait convergence but disentangling this effect from those of shared ecology, evolutionary history, and niche conservatism is often challenging. Here by focusing on wing colour pattern variation within and between three butterfly species living in sympatry in a large proportion of their range, we tested the effect of species interactions on trait diversification. These butterflies display a conspicuous iridescent blue coloration on the dorsal side of their wings and a cryptic brownish colour on the ventral side. Combined with an erratic and fast flight, these colour patterns increase the difficulty of capture by predators and contribute to the high escape abilities of these butterflies. We hypothesize that, beyond their direct contribution to predator escape, these wing patterns can be used as signals of escape abilities by predators, resulting in positive frequency-dependent selection favouring convergence in wing pattern in sympatry. To test this hypothesis, we quantified dorsal wing pattern variations of 723 butterflies from the three species sampled throughout their distribution, including sympatric and allopatric situations and compared the phenotypic distances between species, sex and localities. We detected a significant effect of localities on colour pattern, and higher inter-specific resemblance in sympatry as compared to allopatry, consistent with the hypothesis of local convergence of wing patterns. Our results provide support to the existence of escape mimicry in the wild and stress the importance of estimating trait variation within species to understand trait variation between species, and to a larger extent, trait diversification at the macro-evolutionary scale.
物种相互作用，如拟态，可以促进特征趋同，但要将这种作用与共享生态、进化历史和生态位保守性的作用区分开来，往往具有挑战性。在这里，我们通过关注三种生活在同域范围内大部分区域的蝴蝶物种的翅膀颜色图案变化，来检验物种相互作用对特征多样化的影响。这些蝴蝶的翅膀在背部有明显的虹彩蓝色，在腹部有隐蔽的棕色。结合不规则和快速的飞行，这些颜色图案增加了捕食者捕获的难度，提高了这些蝴蝶的高逃脱能力。我们假设，除了对捕食者逃脱的直接贡献外，这些翅膀图案还可以作为捕食者逃避能力的信号，导致在同域中翅膀图案的趋同出现正频率依赖性选择。为了验证这个假设，我们对来自三个物种的 723 只蝴蝶的翅膀图案进行了量化，这些蝴蝶在其分布范围内进行了采样，包括同域和异域情况，并比较了物种、性别和地点之间的表型距离。我们检测到地点对颜色图案有显著影响，同域的种间相似性高于异域，这与翅膀图案的局部趋同假说一致。我们的研究结果支持了野外逃逸拟态的存在，并强调了在理解种间特征变异和更广泛地在宏观进化尺度上理解特征多样化时，估计种内特征变异的重要性。
