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.

消费者物种内部的演化分化可对当地生态群落施加选择压力，进而影响猎物群落结构。目前尚不清楚这类生态位构建（niche construction）能够在多大程度上沿食物网扩散，并塑造竞争物种的性状变异。本研究旨在检验：滤食性鱼类西鲱（alewife, *Alosa pseudoharengus*）的不同生活史变异体所介导的生态位构建，是否能够驱动竞争物种蓝鳃太阳鱼（bluegill, *Lepomis macrochirus*）产生表型分化与资源利用模式的改变。我们结合同质园实验（common garden experiment）与比较野外调查发现：相较于来自分布有溯河洄游型（anadromous）西鲱或无西鲱的湖泊的蓝鳃太阳鱼，源自内陆型西鲱栖息湖泊的个体，在投喂小型浮游动物时的生长表现相对更优，其鳃耙（gill rakers）更适配小型猎物的捕食需求，且倾向于选择体型更小的浮游动物。在分布有内陆型西鲱的湖泊中，蓝鳃太阳鱼的觅食性状所发生的改变，与西鲱自身的性状变化呈现平行趋势，这表明种间竞争（interspecific competition）引发的是平行表型变化，而非学界通常预测的性状分化。本研究结果提示，物种或可对由竞争优势物种不同生活史变异体所塑造的猎物群落产生局部适应。