Data from: Intraspecific phenotypic variation among alewife populations drives parallel phenotypic shifts in bluegill

Evolutionary diversification within consumer species may generate selection on local ecological communities, affecting prey community structure. However, the extent to which this niche construction can propagate across food webs and shape trait variation in competing species is unknown. Here, we tested whether niche construction by different life-history variants of the planktivorous fish alewife (Alosa pseudoharengus) can drive phenotypic divergence and resource use in the competing species bluegill (Lepomis macrochirus). Using a combination of common garden experiments and a comparative field study, we found that bluegill from landlocked alewife lakes grew relatively better when fed small than large zooplankton, had gill rakers better adapted for feeding on small-bodied prey and selected smaller zooplankton compared with bluegill from lakes with anadromous or no alewife. Observed shifts in bluegill foraging traits in lakes with landlocked alewife parallel those in alewife, suggesting interspecific competition leading to parallel phenotypic changes rather than to divergence (which is commonly predicted). Our findings suggest that species may be locally adapted to prey communities structured by different life-history variants of a competing dominant species.

消费者物种内部的进化分化可对本地生态群落施加选择压力，进而改变猎物群落结构。然而，这种生态位构建（niche construction）能够在食物网中传播，并塑造竞争物种性状变异的程度仍未明确。本研究针对浮游食性鱼类美洲西鲱（alewife, *Alosa pseudoharengus*）的不同生活史变异型所介导的生态位构建，能否驱动竞争物种蓝鳃太阳鱼（bluegill, *Lepomis macrochirus*）的表型分化与资源利用策略展开了测试。本研究结合同质园实验（common garden experiment）与比较野外调查，发现相较于来自有溯河洄游型西鲱或无西鲱湖泊的蓝鳃太阳鱼，来自陆封型西鲱湖泊的蓝鳃太阳鱼在投喂小型浮游动物时的生长表现相对更优，其鳃耙结构更适配小型猎物的摄食需求，且偏好选择更小体型的浮游动物。在存在陆封型西鲱的湖泊中，蓝鳃太阳鱼的觅食性状变化与西鲱自身的性状变化高度趋同，这表明种间竞争引发的是平行表型改变，而非学界通常预测的性状分化。本研究结果显示，物种或可对由竞争优势物种的不同生活史变异型所塑造的猎物群落产生局部适应。