Laboratory of Protozoology, KLB07006, College of Life Science, South China Normal University, Guangzhou 510631, People's Republic of China.
Proc Biol Sci. 2013 Aug 7;280(1768):20131389. doi: 10.1098/rspb.2013.1389. Print 2013 Oct 7.
We propose that delayed predator-prey models may provide superficially acceptable predictions for spurious reasons. Through experimentation and modelling, we offer a new approach: using a model experimental predator-prey system (the ciliates Didinium and Paramecium), we determine the influence of past-prey abundance at a fixed delay (approx. one generation) on both functional and numerical responses (i.e. the influence of present : past-prey abundance on ingestion and growth, respectively). We reveal a nonlinear influence of past-prey abundance on both responses, with the two responding differently. Including these responses in a model indicated that delay in the numerical response drives population oscillations, supporting the accepted (but untested) notion that reproduction, not feeding, is highly dependent on the past. We next indicate how delays impact short- and long-term population dynamics. Critically, we show that although superficially the standard (parsimonious) approach to modelling can reasonably fit independently obtained time-series data, it does so by relying on biologically unrealistic parameter values. By contrast, including our fully parametrized delayed density dependence provides a better fit, offering insights into underlying mechanisms. We therefore present a new approach to explore time-series data and a revised framework for further theoretical studies.
我们提出，延迟的捕食者-猎物模型可能会因为表面上的原因而提供看似合理的预测。通过实验和建模，我们提供了一种新的方法：使用一个模型实验性的捕食者-猎物系统（纤毛虫迪迪虫和草履虫），我们确定了在固定延迟（大约一个世代）下过去猎物丰度对功能和数量响应（即当前：过去猎物丰度对摄食和生长的影响）的影响。我们揭示了过去猎物丰度对两种反应的非线性影响，两种反应的反应方式不同。在模型中包含这些反应表明，数量反应的延迟会导致种群振荡，这支持了一个被广泛接受（但未经检验）的观点，即繁殖而不是摄食高度依赖于过去。我们接下来指出延迟如何影响短期和长期的种群动态。至关重要的是，我们表明，尽管表面上看，对模型进行简化的标准方法可以合理地拟合独立获得的时间序列数据，但它是通过依赖于生物学上不合理的参数值来实现的。相比之下，包含我们完全参数化的延迟密度依赖性提供了更好的拟合，为潜在机制提供了深入的了解。因此，我们提出了一种新的方法来探索时间序列数据，并为进一步的理论研究提供了一个修订的框架。
