Cabon Lilian, Varma Mahendra, Winter Gabe, Ebeling Anne, Schielzeth Holger
Population Ecology Group, Institute of Biodiversity, Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Straße 159, 07743, Jena, Germany.
Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany.
BMC Ecol Evol. 2025 Sep 16;25(1):94. doi: 10.1186/s12862-025-02447-y.
Evolutionary fitness is determined by the match between an organism's phenotype and its local environment. When mismatched, individuals may disperse to more suitable habitats. For flightless insects, however, the range of dispersal is typically limited. Numerous flightless species have, therefore, evolved a dispersal dimorphism, that is, some individuals in otherwise short-winged populations develop long wings. Wing development may be genetically or environmentally determined, but these two drivers have rarely been analysed together.
We studied the inheritance and density-dependent plasticity in the dispersal dimorphism of the meadow grasshopper Pseudochorthippus parallelus. Using a full-sib half-sib breeding design, we found that the development of long wings strongly depends on rearing density, with tactile stimulation being the most likely proximate cause. Additionally, we found heritable variation in the development of long wings, both in the propensity to produce long wings and in response to density (genotype-by-environment interactions). While at high and low densities, the environmental effect dominates, genetic variation is most consequential at intermediate densities.
Our results have implications for the phenotype-environment match and ultimately the evolution of individualised niches. Induced dimorphisms represent a form of adaptive phenotypic plasticity by offering a much greater potential for active niche choice and both genetic and induced dispersal dimorphisms facilitate niche choice in allowing individuals to sample a greater range of environments. Our study shows that niche-related polymorphisms can evolve via selection on the sensitivity threshold.
进化适应性取决于生物体的表型与其当地环境之间的匹配度。当出现不匹配时，个体可能会扩散到更适宜的栖息地。然而，对于不会飞的昆虫来说，其扩散范围通常是有限的。因此，许多不会飞的物种进化出了扩散二态性，也就是说，在原本短翅的种群中，一些个体发育出了长翅。翅的发育可能由基因或环境决定，但这两种驱动因素很少被同时分析。
我们研究了草原蝗虫（Pseudochorthippus parallelus）扩散二态性的遗传和密度依赖性可塑性。通过全同胞半同胞育种设计，我们发现长翅的发育强烈依赖于饲养密度，触觉刺激最有可能是其直接原因。此外，我们发现长翅发育存在可遗传变异，包括产生长翅的倾向以及对密度的反应（基因型与环境的相互作用）。在高密度和低密度情况下，环境效应占主导，而在中等密度时，遗传变异最为重要。
我们的研究结果对表型与环境的匹配以及最终个性化生态位的进化具有启示意义。诱导二态性通过提供更大的主动生态位选择潜力，代表了一种适应性表型可塑性的形式，并且遗传和诱导的扩散二态性都有助于生态位选择，使个体能够接触更广泛的环境。我们的研究表明，与生态位相关的多态性可以通过对敏感性阈值的选择而进化。
