Olivares Manuel, Tiselius Peter, Calbet Albert, Saiz Enric
INSTITUT DE CIéNCIES DEL MAR (ICM, CSIC), PG. MARíTIM DE LA BARCELONETA 37-49, E-08003 BARCELONA, SPAIN.
DEPARTMENT OF BIOLOGICAL AND ENVIRONMENTAL SCIENCES - KRISTINEBERG, UNIVERSITY OF GOTHENBURG, KRISTINEBERG 566, 45178 FISKEBÄCKSKIL, SWEDEN.
J Plankton Res. 2020 Nov 3;42(6):742-751. doi: 10.1093/plankt/fbaa051. eCollection 2020 Nov-Dec.
Predators can induce changes in the diel activity patterns of marine copepods. Besides vertical migration, diel feeding rhythms have been suggested as an antipredator phenotypic response. We conducted experiments to assess the non-lethal direct effects of the predator (northern krill) on the diel feeding patterns of the calanoid copepod . We also analysed the influence of seasonal photoperiod and prey availability on the intensity of copepod feeding rhythms. We did not detect any large effect of krill presence on the diel feeding behaviour of copepods, either in day-night differences or total daily ingestions. Seasonal photoperiod and prey availability, however, significantly affected the magnitude of copepod feeding cycles, with larger diel differences in shorter days and at lower prey concentrations. Therefore, the role of non-lethal direct effects of predators on the diel feeding activity of marine copepods remain debatable and might not be as relevant as in freshwater zooplankton.
捕食者能够引发海洋桡足类动物昼夜活动模式的变化。除垂直迁移外，昼夜摄食节律被认为是一种反捕食者的表型反应。我们开展了实验，以评估捕食者（北方磷虾）对哲水蚤昼夜摄食模式的非致命直接影响。我们还分析了季节性光周期和猎物可利用性对桡足类动物摄食节律强度的影响。无论是在昼夜差异还是每日总摄食量方面，我们均未检测到磷虾的存在对桡足类动物昼夜摄食行为有任何重大影响。然而，季节性光周期和猎物可利用性显著影响了桡足类动物摄食周期的幅度，在较短的白天和较低的猎物浓度下，昼夜差异更大。因此，捕食者对海洋桡足类动物昼夜摄食活动的非致命直接影响的作用仍存在争议，可能不像在淡水浮游动物中那样重要。
