Food differentiation among coexistent species in the field is important strategy for copepods to acquire materials and maintain population stabilization. In situ diet analysis of co-occurring six copepod species in coral waters of the Sanya Bay was conducted using a PCR protocol based on 18S ribosomal gene. Various prey organisms were uncovered, including dinoflagellate, diatom, green algae and plant, protozoa and metazoan. All these spatially coexisting six species showed different dietary diversity, with the food niche breadth (B) ranging from 1.00 (Temora turbinate in morning) to 10.68 (Calanopia elliptica in night). While food overlap between all these copepods were low, with the average value of the diet niche overlap index being approximately 0.09. Even temporally co-existing species sampled from the same time point fed on different groups of prey items with the food overlap index of 0.04 to 0.07 in midday and night but 0 in morning. As the most important dominant copepod in the Sanya Bay, Subeucalanus subcrassus seems to be capable to regulate its feeding, by exhibiting a rhythm of herbivorous feeding in midday and carnivorous feeding in morning and night, to better coordinate with other competitors for utilization of food resources. For most copepods, none of the prey items belonged to the dominant phytoplankton in the ambient water, indicating that copepod can better their survival by widening the choice of potential food resources in food limited environment. The dietary separation observed here might be important strategy for copepod to maintain population stabilization and thriving in the Sanya coastal waters.

中文翻译：

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三亚湾食物受限的热带珊瑚礁中共生co足类之间的饮食分离

田间共存物种之间的食物差异化是co足类动物获取材料和维持种群稳定的重要策略。使用基于18S核糖体基因的PCR方案，对三亚湾珊瑚水域中共生的6种pe足类物种进行了原位饮食分析。发现了各种捕食生物，包括鞭毛藻，硅藻，绿藻和植物，原生动物和后生动物。所有这些在空间上共存的6种物种都具有不同的饮食多样性，其食物生态位宽度（B）范围从1.00（早上的鼻甲为Temora turbinate）到10.68（椭圆形Calanopia）在夜里）。虽然所有这些co足类之间的食物重叠都很低，但饮食生态位重叠指数的平均值约为0.09。甚至从同一时间点在时间上共存的物种都以不同组的猎物为食，其食物重叠指数在中午和晚上为0.04至0.07，而在早晨为0。作为三亚湾最重要的优势pe足，Subeucalanus subcrassus通过在中午表现出草食性进食的节奏，在早晨和晚上展现出肉食性进食的节奏，似乎能够调节其进食，从而更好地与其他竞争者协调利用食物资源。对于大多数co足类动物而言，没有任何猎物属于环境水中占主导地位的浮游植物，这表明co足类动物可以通过在食物有限的环境中扩大潜在食物资源的选择来更好地生存。这里观察到的饮食分离可能是co足类动物维持三亚沿海水域人口稳定和繁盛的重要策略。