Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.
Sci Rep. 2020 Dec 18;10(1):22322. doi: 10.1038/s41598-020-79165-6.
Late developmental stages of the marine copepods in the genus Calanus can spend extended periods in a dormant stage (diapause) that is preceded by the accumulation of large lipid stores. We assessed how lipid metabolism during development from the C4 stage to adult is altered in response to predation risk and varying food availability, to ultimately understand more of the metabolic processes during development in Calanus copepods. We used RNA sequencing to assess if perceived predation risk in combination with varied food availability affects expression of genes associated with lipid metabolism and diapause preparation in C. finmarchicus. The lipid metabolism response to predation risk differed depending on food availability, time and life stage. Predation risk caused upregulation of lipid catabolism with high food, and downregulation with low food. Under low food conditions, predation risk disrupted lipid accumulation. The copepods showed no clear signs of diapause preparation, supporting earlier observations of the importance of multiple environmental cues in inducing diapause in C. finmarchicus. This study demonstrates that lipid metabolism is a sensitive endpoint for the interacting environmental effects of predation pressure and food availability. As diapause may be controlled by lipid accumulation, our findings may contribute towards understanding processes that can ultimately influence diapause timing.
海洋桡足类中的 Calanus 属的后生动物发育后期可以进入休眠阶段（滞育），在此之前会积累大量的脂肪储备。我们评估了从 C4 阶段到成年的发育过程中，脂代谢如何响应捕食风险和不同的食物可利用性而发生改变，从而更深入地了解 Calanus 桡足类发育过程中的代谢过程。我们使用 RNA 测序来评估感知到的捕食风险与不同的食物可利用性是否会影响与脂代谢和滞育准备相关的基因在 C. finmarchicus 中的表达。脂代谢对捕食风险的反应因食物的可利用性、时间和生命阶段而异。在高食物条件下，捕食风险会导致脂分解代谢上调，而在低食物条件下则下调。在低食物条件下，捕食风险会破坏脂肪积累。桡足类动物没有明显的滞育准备迹象，这支持了早先观察到的在诱导 C. finmarchicus 滞育时多种环境线索的重要性。这项研究表明，脂代谢是捕食压力和食物可利用性相互作用的环境影响的一个敏感终点。由于滞育可能受脂肪积累的控制，我们的发现可能有助于理解最终可能影响滞育时间的过程。
