Data from: Naturally occurring variation in tadpole morphology and performance linked to predator regime

Divergent natural selection drives a considerable amount of the phenotypic and genetic variation observed in natural populations. For example, variation in the predator community can generate conflicting selection on behavioral, life-history, morphological, and performance traits. Differences in predator regime can subsequently increase phenotypic and genetic variations in the population and result in the evolution of reproductive barriers (ecological speciation) or phenotypic plasticity. We evaluated morphology and swimming performance in field collected Bronze Frog larvae (Lithobates clamitans) in ponds dominated by predatory fish and those dominated by invertebrate predators. Based on previous experimental findings, we hypothesized that tadpoles from fish-dominated ponds would have small bodies, long tails, and large tail muscles and that these features would facilitate fast-start speed. We also expected to see increased tail fin depth (i.e., the tail-lure morphology) in tadpoles from invertebrate-dominated ponds. Our results support our expectations with respect to morphology in affecting swimming performance of tadpoles in fish-dominated ponds. Furthermore, it is likely that divergent natural selection is playing a role in the diversification on morphology and locomotor performance in this system.

趋异自然选择（divergent natural selection）是自然种群中广泛观测到的大量表型与遗传变异的核心驱动因子。例如，捕食者群落的差异可对行为、生活史、形态及性能相关性状施加冲突性选择压力。捕食者群落格局的差异继而可提升种群内的表型与遗传变异，并可能导致生殖隔离（生态物种形成，ecological speciation）的演化或表型可塑性的产生。本研究针对以捕食性鱼类为主的池塘，以及以无脊椎动物捕食者为主的池塘中的野外采集青铜蛙（Lithobates clamitans）幼体，开展了形态学与游泳性能评估。基于既往实验研究结果，本研究提出如下假说：来自鱼类主导池塘的蝌蚪将拥有较小的躯体、更长的尾部与更发达的尾部肌肉，此类形态特征可提升其快速启动游泳速度。同时我们预期，来自无脊椎动物主导池塘的蝌蚪将拥有更高的尾鳍高度（即尾部诱饵形态，tail-lure morphology）。针对鱼类主导池塘中的蝌蚪，本研究结果证实了形态特征对其游泳性能的影响与我们的预期相符。此外，本研究体系中的形态与运动性能多样性，极有可能受到趋异自然选择的调控。