Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, SE-106 91, Sweden.
Ecology. 2017 Jan;98(1):228-238. doi: 10.1002/ecy.1633.
Variation in selection among populations and years has important implications for evolutionary trajectories of populations. Yet, the agents of selection causing this variation have rarely been identified. Selection on the time of reproduction within a season in plants might differ both among populations and among years, and selection can be mediated by both mutualists and antagonists. We investigated if differences in the direction of phenotypic selection on flowering phenology among 20 populations of Gentiana pneumonanthe during 2 yr were related to the presence of the butterfly seed predator Phengaris alcon, and if butterfly incidence was associated with the abundance of the butterfly's second host, Myrmica ants. In plant populations without the butterfly, phenotypic selection favored earlier flowering. In populations where the butterfly was present, caterpillars preferentially attacked early-flowering individuals, shifting the direction of selection to favoring later flowering. Butterfly incidence in plant populations increased with ant abundance. Our results demonstrate that antagonistic interactions can shift the direction of selection on flowering phenology, and suggest that such shifts might be associated with differences in the community context.
种群和年份之间的选择变化对种群的进化轨迹有重要影响。然而，导致这种变化的选择因素很少被确定。植物在一个季节内繁殖时间的选择可能在不同种群和不同年份之间存在差异，并且选择可以由互利共生体和拮抗物介导。我们调查了在 2 年期间，20 个肺形草种群中开花物候的表型选择方向的差异是否与蝴蝶种子捕食者阿尔康凤蝶的存在有关，以及蝴蝶的发生率是否与蝴蝶的第二宿主拟黑多刺蚁的丰度有关。在没有蝴蝶的植物种群中，表型选择有利于更早的开花。在有蝴蝶存在的种群中，毛毛虫更倾向于攻击早开花的个体，从而改变了选择的方向，有利于晚开花。植物种群中蝴蝶的发生率随着蚂蚁数量的增加而增加。我们的研究结果表明，拮抗相互作用可以改变开花物候的选择方向，并表明这种转变可能与群落环境的差异有关。
