We determined numerical response, functional response, and prey selection by the predator Asplanchna girodi using 4 brachionid rotifer species, varying in size and lorica spines. We hypothesized that the consumption by the predators and thus population growth rates would be highest on prey with small spines compared with those with long spines. Data on the numerical response study showed that the population growth patterns of A. girodi were significantly influenced by prey species and density. With greater prey availability, the populations of the predator reached higher densities. At any given prey density, population densities of A. girodi were higher when feeding on Plationus patulus and Brachionus angularis than on B. rubens and B. havanaensis. The highest numbers of males were produced on diets of B. havanaensis and P. patulus. The rate of population increase ranged between 0.2 and 0.4 d⁻¹ and was highest when feeding on a diet of P. patulus. A. girodi showed type II functional response for all the tested prey species. Among the 4 prey taxa tested, A. girodi showed the highest preference for B. angularis, regardless of its density. By contrast, it avoided B. rubens and P. patulus completely. These observations corroborate our hypothesis and suggest that prey morphology is an important determinant in prey selection by nonvisual predators such as Asplanchna.

我们确定了食肉动物Asplanchna girodi的数值响应，功能响应以及对猎物的选择，其中使用了4种大小不等和轮虫刺的轮虫轮虫。我们假设，与长刺相比，小刺的捕食者的消费量因而人口增长率最高。数值响应研究的数据表明，吉罗迪拟南芥的种群增长模式受到猎物种类和密度的显着影响。随着猎物可用性的提高，捕食者的种群密度也随之提高。在任何给定的猎物密度，人口密度A. girodi在喂奶时较高Plationus patulus和臂角突比B. rubens和B. havanaensis好。男性的最高数字是对饮食产生B. havanaensis和P. patulus。种群增长速度在0.2到0.4 d ^-1之间，并且以斑纹对虾饮食为最高。Girodi拟南芥对所有被测猎物均表现出II型功能性反应。在测试的4猎物类群，A. girodi显示最高偏好B.角突，而不管其密度。与此相反，它避免了B.鲁本斯和P. patulus完全。这些观察结果证实了我们的假设，并暗示了猎物的形态是非视觉掠食者如Asplanchna选择猎物的重要决定因素。