Abstract Light is one of the most important structuring factors for life in aquactic biology. For zooplankton grazers, including copepods, light offers a behavioral dilemma that is potentially present at both small and large scales. We investigated the grazing rate, clearance rate, fecal pellet production rate, egg production rate, percertage of egg hatching and survival percentage of the freshwater copepod Thermocyclops deceipiens under different light intensities (0 lx, 500 lx, 1500 lx) over periods of 15 days. For the grazing experiment the fresh water microalgae Chlorella vulgaris was used at concentrations 2–6 × 106 cells/mL−1. The grazing rates of the copepod decreased at higher light intensities when compared to other treatments. Maximum grazing rate and the clearance rate occurred in the treatment with 500 lx (70,490 cells copepod−1 h−1, 0.23 mL copepod−1 h−1). Egg production rate and hatching rate percentage (17.4 eggs female−1 day−1, 99 ± 0.98%) were also higher at the algae fed with 500 lx light intensity. Copepods survived well and continuously produced fecal pellets on a 500 lx light intensity diet of Chlorella vulgaris. The results suggest that low light intensity influenced the grazing rate, fecundity and survival of copepod T.decipiens.

中文翻译：

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淡水桡足类 Thermocyclops decipiens (Kiefer, 1929) 在不同光照强度下对普通小球藻的放牧率

摘要 光是水生生物中最重要的生命结构因素之一。对于浮游动物食草动物，包括桡足类动物，光提供了一种行为困境，可能在小规模和大尺度上都存在。我们调查了淡水桡足类 Thermocyclops deceipiens 在 15 天的不同光照强度（0 lx、500 lx、1500 lx）下的放牧率、清除率、粪便颗粒产生率、产蛋率、卵孵化率和存活率. 对于放牧实验，淡水微藻普通小球藻以 2–6 × 106 个细胞/mL-1 的浓度使用。与其他处理相比，桡足类的放牧率在较高的光照强度下下降。最大放牧率和清除率发生在 500 lx（70,490 个桡足类细胞-1 h-1, 0. 23 mL 桡足类-1 h-1）。在以 500 lx 光强度喂养的藻类中，产蛋率和孵化率百分比（17.4 个雌性-1 天-1，99 ± 0.98%）也更高。桡足类在普通小球藻的 500 lx 光照强度下存活良好并持续产生粪便颗粒。结果表明，低光照强度影响桡足类T.decipiens的放牧率、繁殖力和存活率。