Feeding behaviour of the nauplii of the marine calanoid copepod Paracartia grani Sars: Functional response, prey size spectrum, and effects of the presence of alternative prey
Feeding behaviour of the nauplii of the marine calanoid copepod Paracartia grani Sars: Functional response, prey size spectrum, and effects of the presence of alternative prey
复制标题
海洋桡足类 Paracartia grani Sars 无节幼体的摄食行为：功能反应、猎物大小谱以及替代猎物存在的影响
作者：
Laura K Helenius;E. Saiz
通过室内摄食实验，研究了花椒类桡足类Paracartia grani Sars幼体期的功能反应和猎物尺寸谱。实验是在一系列不同大小和运动模式的微藻猎物上进行的。4.5 ~ 19.8 μm的猎物均存在显著的摄食反应，大多数猎物类型均存在Holling III型功能反应。以异鞭毛藻（Heterocapsa sp.）和硅藻（thalassisira weissflogii）为食时清除率最高（分别为0.61和0.70 mL / d-1），表明最佳食食比为0.09。另外还进行了其他实验，以研究替代猎物（Heterocapsa sp.或Gymnodinium litoralis）的存在对褐藻Isochrysis galbana的功能反应的影响。在双藻混合物中，galbana的清除率和摄食率在功能反应范围内显着降低，因为对较大的替代猎物有选择性。矛盾的是，相对较大的猎物在鹦鹉螺中引发了感知反应，但很可能这样的猎物不能完全被吃掉，可能会出现一定程度的草率进食。我们的研究结果进一步证明了复杂的猎物特异性摄食相互作用可能发生在几种可用猎物类型的自然组合中。
Laboratory feeding experiments were conducted to study the functional response and prey size spectrum of the young naupliar stages of the calanoid copepod Paracartia grani Sars. Experiments were conducted on a range of microalgal prey of varying sizes and motility patterns. Significant feeding was found in all prey of a size range of 4.5–19.8 μm, with Holling type III functional responses observed for most prey types. The highest clearance rates occurred when nauplii fed on the dinoflagellate Heterocapsa sp. and the diatom Thalassiosira weissflogii (respectively, 0.61 and 0.70 mL ind-1 d-1), suggesting an optimal prey:predator ratio of 0.09. Additional experiments were conducted to examine the effects of the presence of alternative prey (either Heterocapsa sp. or Gymnodinium litoralis) on the functional response to the haptophyte Isochrysis galbana. In the bialgal mixtures, clearance and ingestion rates of I. galbana along the range of the functional response were significantly reduced as a result of selectivity towards the larger, alternative prey. Paradoxically, relatively large prey trigger a perception response in the nauplii, but most likely such prey cannot be completely ingested and a certain degree of sloppy feeding may occur. Our results are further evidence of the complex prey-specific feeding interactions that are likely to occur in natural assemblages with several available prey types.