Ding Zixuan, Sun Xiaohong, Qiao Yiming, Liu Ying, Liu Jihua
Marine College, Shandong University, Weihai 264209, China.
Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China.
Animals (Basel). 2023 Oct 6;13(19):3116. doi: 10.3390/ani13193116.
The feeding relationship between copepods and phytoplankton has immense ecological significance. This study investigated the feeding behavior of copepods by studying the feeding selectivity of , a key small copepod species, using a high-speed camera. The feeding behavior of separately fed on three algae, , and , was studied at five different concentrations. The factors characterizing feeding behavior, including the beating frequency (BF), beating time (BT), and rejection behavior, were analyzed. The average BT and BF of fed on toxic algae were significantly lower than those of copepods fed on nontoxic algae, indicating that the toxic algae negatively affected their feeding behavior. There were no significant differences in feed rejection among the three algae during the short period of experimentation, indicating that the rejection behavior was insignificant in the early period (within 20 min) of feeding on toxic algae. The feeding behavior was inhibited when the concentration reached 250 cells/mL. The BT was initially affected at increasing concentrations followed by the BF, and and . reduced the BF at concentrations of 250 and 1000 cells/mL, respectively. Analysis of the average BFs revealed that was more significantly affected by containing diarrheal shellfish poison than by . containing paralytic shellfish poison. The BF of copepods fed on was significantly lower than that of copepods fed on . at 250-500 cells/mL but was not significantly different from that at 1000 cells/mL. This indicated that the inhibitory effect of on the feeding behavior was more significant at concentrations observed at the onset of red tide blooms (0.25-0.5 × 10 cells/mL), but insignificant at concentrations reaching those in advanced red tides (>10 cells/mL). This study demonstrates that toxic dinoflagellates alter the feeding behavior of copepods and describes the variations in their feeding response to different algal species and concentrations. The findings provide crucial insights for further studies on the feeding relationship between copepods and phytoplankton and on functional assessment of plankton ecosystems.
桡足类与浮游植物之间的摄食关系具有巨大的生态意义。本研究通过使用高速摄像机研究关键小型桡足类物种的摄食选择性，来调查桡足类的摄食行为。在五种不同浓度下，研究了单独以三种藻类，即[藻类名称1]、[藻类名称2]和[藻类名称3]为食的[桡足类物种名称]的摄食行为。分析了表征摄食行为的因素，包括跳动频率（BF）、跳动时间（BT）和拒食行为。以有毒藻类为食的[桡足类物种名称]的平均BT和BF显著低于以无毒藻类为食的桡足类，这表明有毒藻类对其摄食行为产生了负面影响。在短时间的实验中，三种藻类之间的拒食情况没有显著差异，这表明在摄食有毒藻类的早期阶段（20分钟内），拒食行为并不明显。当浓度达到250个细胞/毫升时，摄食行为受到抑制。随着浓度增加，BT首先受到影响，随后是BF，[具体物种1]和[具体物种2]分别在250和1000个细胞/毫升的浓度下降低了BF。对平均BF的分析表明，与含有麻痹性贝类毒素的[藻类名称]相比，[桡足类物种名称]受含有腹泻性贝类毒素的[藻类名称]的影响更大。在250 - 500个细胞/毫升时，以[藻类名称1]为食的桡足类的BF显著低于以[藻类名称2]为食的桡足类，但在1000个细胞/毫升时没有显著差异。这表明[藻类名称1]对摄食行为的抑制作用在赤潮爆发初期观察到的浓度（0.25 - 0.5×10个细胞/毫升）时更为显著，但在达到赤潮后期浓度（>10个细胞/毫升）时不显著。本研究表明有毒甲藻会改变桡足类的摄食行为，并描述了它们对不同藻类物种和浓度的摄食反应变化。这些发现为进一步研究桡足类与浮游植物之间的摄食关系以及浮游生物生态系统的功能评估提供了关键见解。
