Abstract Although consumers may use selective feeding to cope with suboptimal resource quality, little work has examined the mechanisms that underlie selective feeding, the efficiency of this behavior or its influence on consumer growth rate. Furthermore, a consumer’s exposure to suboptimal resources may also influence the consumer’s behavior and life history, including growth rate. Here, we studied how the availability of P-rich and P-poor phytoplankton influences the growth and behavior of copepod nauplii. We observed that copepod nauplii preferentially feed on P-rich prey. We also found that even relatively short exposure to P-rich phytoplankton yielded higher nauplii growth rates, whereas the presence of P-poor phytoplankton in a mixture impaired growth. Overall, we observed that swimming speed decreased with increasing phytoplankton P-content, which is a behavioral adjustment that may improve utilization of heterogeneously distributed high-quality food in the field. Based on our results, we propose that the optimal prey C: P ratio for copepod nauplii is very narrow, and that deviations from this optimum have severe negative consequences for growth.

中文翻译：

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时间和比例问题：富磷浮游植物的可用性影响桡足类无节幼体的生长和行为

摘要 尽管消费者可能会使用选择性喂养来应对次优的资源质量，但很少有工作研究过选择性喂养的机制、这种行为的效率或其对消费者增长率的影响。此外，消费者接触次优资源也可能影响消费者的行为和生活史，包括增长率。在这里，我们研究了富磷和贫磷浮游植物的可用性如何影响桡足类无节幼体的生长和行为。我们观察到桡足类无节幼体优先以富含磷的猎物为食。我们还发现，即使相对较短的暴露于富含磷的浮游植物也会产生更高的无节幼体生长率，而在混合物中存在贫磷的浮游植物会损害生长。总体而言，我们观察到游泳速度随着浮游植物 P 含量的增加而降低，这是一种行为调整，可以提高该领域异质分布的优质食品的利用率。根据我们的结果，我们建议桡足类无节幼体的最佳猎物 C:P 比率非常窄，并且偏离该最佳值会对生长产生严重的负面影响。