Resident-disperser differences and genetic variability affect communities in microcosms

Dispersal is a key process mediating ecological and evolutionary dynamics. Its effects on the dynamics of spatially-structured systems, population genetics, or species range distribution can depend on phenotypic differences between dispersing and non-dispersing individuals. However, scaling up the importance of resident-disperser differences to communities and ecosystems has rarely been considered, in spite of intraspecific phenotypic variability being an important factor mediating community structure and productivity. Here, we used the ciliate Tetrahymena thermophila, in which phenotypic traits are known to differ between residents and dispersers, to test (i) whether these resident-disperser differences affect biomass and composition in competitive communities composed of four other Tetrahymena species, and (ii) whether these effects are genotype-dependent. We found that dispersers led to lower community biomass compared to residents. This effect was highly consistent across the twenty...

扩散是调控生态与进化动态的核心过程。其对空间结构化系统动态、种群遗传学或物种分布范围的影响，通常取决于扩散个体与非扩散个体间的表型差异。尽管种内表型变异是调控群落结构与生产力的关键因素，但目前极少有研究将定居者与扩散者间的差异的重要性拓展至群落与生态系统尺度。本研究以嗜热四膜虫（Tetrahymena thermophila）为实验材料——该物种的定居者与扩散者已被证实存在表型性状差异——开展两项检验：(i) 此类定居者-扩散者差异是否会影响由另外四种四膜虫物种构成的竞争性群落的生物量与群落组成；(ii) 此类效应是否具有基因型依赖性。研究发现，与定居者相比，扩散者会导致群落生物量降低。该效应在20个……