Rodríguez-Barreras Ruber, Godoy-Vitorino Filipa, Præbel Kim, Wangensteen Owen S
Department of Biology, University of Puerto Rico at Bayamón, Zona Industrial Minillas, 170, PR-174, Bayamón, 00959-1919, Puerto Rico.
Department of Microbiology and Medical Zoology, University of Puerto Rico School of Medicine, Paseo Dr. José Celso Barbosa, San Juan, 00936, Puerto Rico.
Reg Stud Mar Sci. 2020 Nov;40. doi: 10.1016/j.rsma.2020.101537. Epub 2020 Nov 10.
Detailed information of trophic interactions among consumer-resources in food webs is usually limited due to the lack of accurate identification of eaten food resources. The use of DNA-metabarcoding has been proven useful for molecular identification of the numerous taxa present in stomach contents. Here, we characterize the diet and trophic behavior of four sea urchin species inhabiting shallow waters of Puerto Rico using this molecular technique. We extracted, sequenced, and analyzed DNA from the gut content of a total of 60 individuals collected at three sites at the northeastern coast of Puerto Rico. Our results demonstrated that seaweeds were the dominant food source for the four sea urchin species at all three sites, but also small protists, fungi and metazoans were important components of sea urchin's diet. Interspecific differences in diet were also found among sites. PERMANOVA analysis detected significant differences among species (Pseudo-F = 1.755, p < 0.001), and among sites (Pseudo-F = 2.52, p < 0.001). A SIMPER analysis showed that in all cases the main taxa causing differences between species and sites were macroalgae (Rhodophyta, Chlorophyta and Ochrophyta) with some contribution of small eukaryotes (Apicomplexa and Bacillariophyta). This diet characterization in sea urchins revealed a generalist omnivore behavior, but with a clear dominance of algae as a main dietary component. Thus, we found a potential inter-specific competition due to niche overlapping, which seems to be more common than initially thought.
由于缺乏对所食食物资源的准确鉴定，食物网中消费者与资源之间营养相互作用的详细信息通常有限。DNA代谢条形码技术已被证明可用于分子鉴定胃内容物中存在的众多分类群。在此，我们使用这种分子技术对栖息在波多黎各浅水区的四种海胆的饮食和营养行为进行了表征。我们从波多黎各东北海岸三个地点采集的总共60个个体的肠道内容物中提取、测序并分析了DNA。我们的结果表明，在所有三个地点，海藻都是这四种海胆的主要食物来源，但小型原生生物、真菌和后生动物也是海胆饮食的重要组成部分。在不同地点之间也发现了种间饮食差异。PERMANOVA分析检测到物种之间存在显著差异（伪F = 1.755，p < 0.001），地点之间也存在显著差异（伪F = 2.52，p < 0.001）。SIMPER分析表明，在所有情况下，导致物种和地点之间差异的主要分类群是大型藻类（红藻门、绿藻门和褐藻门），小型真核生物（顶复门和硅藻门）也有一定贡献。这种对海胆饮食的表征揭示了一种广食性杂食行为，但藻类作为主要饮食成分明显占主导地位。因此，我们发现由于生态位重叠存在潜在的种间竞争，这种情况似乎比最初认为的更为常见。
