Data from: Heterospecific courtship, minority effects and niche separation between cryptic butterfly species.

Species interacting in varied ecological conditions often evolve in different directions in different local populations. The butterflies of the cryptic Leptidea complex are sympatrically distributed in different combinations across their Eurasian range. Interestingly, the same species is a habitat generalist in some regions and a habitat specialist in others, where a sibling species has the habitat generalist role. Previous studies suggest that this geographically variable niche divergence is generated by local processes in different contact zones. By varying the absolute and relative densities of Leptidea sinapis and Leptidea juvernica in large outdoor cages, we show that female mating success is unaffected by conspecific density, but strongly negatively affected by the density of the other species. Whereas 80% of the females mated when a conspecific couple was alone in a cage, less than 10% mated when the single couple shared the cage with five pairs of the other species. The heterospecific courtships can thus affect the population fitness, and for the species in the local minority, the suitability of a habitat is likely to depend on the presence or absence of the locally interacting species. If the local relative abundance of the different species depends on the colonization order, priority effects might determine the ecological roles of interacting species in this system.在多样生态条件下发生相互作用的物种种群，往往会在不同局域种群中朝不同演化方向发展。隐存莱普蝶（Leptidea）复合种群的蝶类，在其欧亚分布区内以多种组合形式实现同域分布。有趣的是，同一莱普蝶物种种群在部分区域为生境广适种，而在另一区域则成为生境特化种，此时其近缘姊妹种便充当了生境广适种的角色。既往研究表明，这种具有地理异质性的生态位分化，源于不同物种接触带内的局域演化过程。本研究通过在大型室外笼舍中调控辛氏莱普蝶（Leptidea sinapis）与朱尔维纳莱普蝶（Leptidea juvernica）的绝对密度与相对比例，发现雌性个体的交配成功率不受同种密度影响，但会显著受到异种密度的负面制约。当单对同种个体单独置于笼舍中时，有80%的雌性个体成功交配；而当单对同种个体与5对异种个体共处于同一笼舍时，成功交配的雌性个体占比不足10%。由此可见，异种求偶行为会影响种群适合度；而对于局域种群中占比偏少的物种而言，其生境适宜性大概率取决于当地相互作用物种的存在与否。若不同物种种群的局域相对丰度取决于定殖先后顺序，则优先效应可能决定该系统中相互作用物种的生态功能角色。