Data from: Evaluation of alternative prey-, predator-, and ratio-dependent functional response models in a zooplankton microcosm

There is strenuous debate among ecologists regarding the inclusion of predator density into the originally prey- dependent functional response. We provided comprehensive empirical comparisons of alternative functional response models for the predatory ostracod Heterocypris incongruens (Ramdohr, 1808) and the rotifer Brachionus calyciflorus (Pallas, 1766) as its prey in small freshwater microcosms. Prey killed was measured at factorial combinations of four predator densities and five prey densities, and was recorded at 3 min intervals over 60 min experiments. To support the potential effect of predator interference on per capita kill rate, we recorded ostracod activity and aggression. Kill rate increased following a saturating function with increasing prey density and decreased with increasing predator density. Model evaluation using an information–theoretic approach indicated that the Arditi–Ginzburg type II ratio-dependent model performed best, followed by the Arditi–Akcakaya and Beddington–DeAngelis type II predator-dependent models, suggesting that predator interference was important in predicting kill rates. Interference among predators increased and their activity decreased with increasing predator density, providing confirmation that interference was responsible for the predator-dependent effect. By combining a microcosm experiment and behavioral observations, our results suggest that predator interference at realistic population densities influences ostracod kill rates and this form of interference was best accommodated by predator-dependent models.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~The ‘well’ is the arena in which the predator-prey microcosm experiments we conducted. The total volume of water held in the well (well_vol) was 2.75 ml.Date: Date the trial was completedWell ID: Row and Column of PlateThe dates and wells could be combined to create a unique trial ID in most cases.P.well: Number of ostracods per wellP: Ostracod density, individuals/mlN.well: Number of rotifers per wellN: Rotifer density, individuals/mlkilled: Number of Rotifers killed during observationI would count the number of rotifers consistently throughout the hour trial period. The interval between counting was about 3 mins. Thus, there is a minimum time that this depletion could have occurred (min.time) or a maximum time (max.time) based on the time since I last checked the well (multiple wells during an hour had predator and prey combinations, so I was checking a multiple in a given hour). When the time seems high that does not mean that the wells were not checked, it means that depletion didn’t occur until that interval. An average time was used for the paper, to calculate the kill per min, per predator.生态学家们围绕是否应将捕食者密度纳入最初基于猎物的功能响应模型，存在激烈的学术争论。本研究针对小型淡水微宇宙（freshwater microcosms）中的捕食性介形类异饰尾介（Heterocypris incongruens, Ramdohr, 1808）及其猎物萼花臂尾轮虫（Brachionus calyciflorus, Pallas, 1766），对多种备选功能响应模型开展了全面的实证比较。实验设置了4个捕食者密度与5个猎物密度的因子组合，记录了被捕食的猎物数量，整个60分钟的实验过程中以3分钟为间隔进行数据采集。为验证捕食者干扰对单位捕食率的潜在影响，本研究同步记录了介形类的活动与攻击行为。单位捕食率随猎物密度升高呈饱和函数增长，而随捕食者密度升高而下降。采用信息论方法开展模型评估后发现，Arditi–Ginzburg II型比率依赖模型表现最优，其次为Arditi–Akcakaya与Beddington–DeAngelis II型捕食者依赖模型，这表明捕食者干扰对捕食率的预测具有重要意义。捕食者间的干扰程度随捕食者密度升高而增强，而其活动水平则随之下降，这证实了捕食者干扰正是产生捕食者依赖效应的原因。结合微宇宙实验与行为观测的结果表明，在真实种群密度下的捕食者干扰会影响异饰尾介的捕食率，而这类干扰效应可通过捕食者依赖模型得到最佳拟合。 本研究开展的捕食者-猎物微宇宙实验均在孔板孔（well）中进行，单个孔板孔的总装液量（well_vol）为2.75毫升。 试验日期：完成试验的具体日期 孔编号（Well ID）：培养板的行与列编号 多数情况下，可结合试验日期与孔编号生成唯一的试验ID。 单孔介形类数量（P.well）：每个孔中的介形类个体数 介形类密度（P）：单位毫升个体数 单孔轮虫数量（N.well）：每个孔中的轮虫个体数 轮虫密度（N）：单位毫升个体数 被捕食轮虫数（killed）：观测时段内被捕食的轮虫总数 本研究在整个1小时试验周期内持续计数轮虫数量，计数间隔约为3分钟。基于上一次检查孔板孔的时间，可推算猎物消耗发生的最早时间（min.time）与最晚时间（max.time）——由于1小时内需处理多个包含捕食者-猎物组合的孔板孔，单次试验中需依次检查多个孔位。若间隔时间较长，并不代表未对该孔进行检查，仅表示猎物消耗直至该间隔时段才发生。本研究在论文中采用平均间隔时间来计算每只捕食者每分钟的捕食量。