Copepods are important grazers on toxic phytoplankton and serve as vectors for algal toxins up the marine food web. Success of phytoplankton depends among other factors on protection against grazers like copepods, and same way copepod survival and population resilience relies on their ability to escape predators. Little is, however, known about the effect of toxins on the escape response of copepods. In this study we experimentally tested the hypothesis that the neurotoxin domoic acid (DA) produced by the diatom Pseudo-nitzschia affects escape responses of planktonic copepods. We found that the arctic copepods Calanus hyperboreus and C. glacialis reduced their escape response after feeding on a DA-producing diatom. The two species were not affected the same way; C. hyperboreus was affected after shorter exposure and less intake of DA. The negative effect on escape response was not related to the amount of DA accumulated in the copepods. Our results suggest that further research on the effects of DA on copepod behavior and DA toxicity mechanisms is required to evaluate the anti-grazing function of DA.

pe足类是有毒浮游植物的重要放牧者，并作为海洋食物网上藻类毒素的媒介。浮游植物的成功除其他因素外，还取决于对诸如co足类等掠食者的保护，而pe足类动物的生存和种群适应力的相同方式也取决于其逃避捕食者的能力。然而，关于毒素对co足类动物逃避反应的影响知之甚少。在这项研究中，我们通过实验验证了以下假设：硅藻假奈茨菌产生的神经毒素多摩酸（DA）影响浮游co足类的逃逸反应。我们发现北极co足类Calanus hyperboreus和C. glacialis摄食产生DA的硅藻后，它们的逃逸反应降低。这两个物种没有以相同的方式受到影响。短暴露时间和少摄取DA后，高硼酸梭菌受到了影响。对逃避反应的负面影响与the足类动物体内积累的DA量无关。我们的结果表明，需要进一步研究DA对co足类行为和DA毒性机制的影响，以评估DA的抗放牧功能。