Functional response models describe the relationship between prey density and per capita prey consumption rate by a predator. Type II functional responses, in which density‐dependent predation occurs via a decelerating feeding rate, seem to prevail in nature and are commonly described by Holling’s disk equation. In the derivation of the disk equation, Holling did not include digestion time. Although some authors have later extended the interpretation of handling time by also including digestion time, this violates the key assumption of the disk equation that the processes of searching for and handling prey are mutually exclusive. The steady‐state satiation (SSS) equation is a functional response model that discriminates between handling and digestion time. The application of the SSS equation is underutilized so far in the ecological literature, probably due to its complexity. In this study, we first tested the viability of the SSS equation. Second, we investigated the mechanistic basis of the SSS equation, comparing the model’s predictions with directly observed data. For this purpose, we used predator–prey systems of different taxa, that is, the ladybird beetle Hippodamia variegata preying on the aphid Aphis fabae, the lacewing Chrysoperla agilis preying on the aphid Myzus persicae, and the predatory mite Iphiseius degenerans preying on the thrips Frankliniella occidentalis. Our results show that the SSS equation is viable and can realistically describe type II functional response. In all predator–prey systems we tested, the model fitted the data reasonably well and provided realistic estimation of its parameters.

中文翻译：

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用功能响应概念对捕食动物进食行为的机理理解

功能反应模型描述了捕食者的猎物密度与人均猎物消耗率之间的关系。II型功能性反应似乎是占主导地位的，通常通过Holling的圆盘方程来描述，其中速度依赖性的掠食通过依赖于密度的捕食而发生。在磁盘方程式的推导中，Holling不包括消化时间。尽管后来一些作者通过包括消解时间扩展了处理时间的解释，但这违反了磁盘方程式的关键假设，即搜索和处理猎物的过程是互斥的。稳态饱和度（SSS）方程是一个功能响应模型，可区分处理时间和消化时间。到目前为止，SSS方程的应用在生态文献中并未得到充分利用，可能是由于其复杂性。在这项研究中，我们首先测试了SSS方程的可行性。其次，我们研究了SSS方程的机理基础，将模型的预测与直接观察到的数据进行了比较。为此，我们使用了不同分类单元的捕食者－被捕者系统，即瓢虫Hippodamia瓢虫捕食蚜虫蚜，该蛉Chrysoperla AGILIS上捕食蚜虫桃蚜和捕食螨Iphiseius degenerans捕食蓟马蓟马。我们的结果表明，SSS方程是可行的，可以现实地描述II型功能响应。在我们测试的所有捕食者－猎物系统中，模型都很好地拟合了数据，并提供了其参数的实际估计。