Evolution of increased intraspecific competitive ability following introduction: the importance of relatedness among genotypes.

1.A long‐standing explanation for invasion success is that invasive plants could evolve to be more competitive following introduction. This evolution of increased competitive ability (EICA) hypothesis, however, has seldom been tested with regard to intraspecific competition. Given that plants can display different responses to related and unrelated conspecifics, the evolution of intraspecific competitive ability might be specific to genotypes of different relatedness. 2.Here, we grew five native (South American) and five introduced (North American) genotypes of the clonal herbaceous invasive plant Alternanthera philoxeroides alone, with aboveground competition from kin (the same genotype) or from one of two types of strangers (another genotype from the same range or another genotype from the other range). 3.When grown alone, introduced and native genotypes produced similar total biomass and storage‐root biomass. However, in response to intraspecific competition, introduced genotyp...1. 关于入侵植物成功定殖扩散的长期经典假说指出，入侵植物在被引入到新的分布区后，可演化出更强的竞争能力。然而，这一**增加竞争能力演化（Evolution of Increased Competitive Ability，EICA）**假说，此前极少有研究针对种内竞争场景开展验证。鉴于植物对亲缘与非亲缘同种个体的响应模式存在显著差异，种内竞争能力的演化可能仅对特定亲缘关系的基因型具有特异性。 2. 本研究以克隆草本入侵植物**空心莲子草（Alternanthera philoxeroides）**为实验材料，分别种植了5个本地（南美）基因型与5个引入（北美）基因型，设置了四种处理：无竞争（单独种植）、来自亲属（同一基因型）的地上竞争、来自两类非亲属的地上竞争——一类为同分布区的其他基因型，另一类为另一分布区的其他基因型。 3. 单独种植条件下，引入种群与本地种群的基因型具有相近的总生物量与储藏根生物量。然而，在应对种内竞争时，引入基因型……