Zooplankton organisms with short generation times, such as rotifers, are ideal models to study general ecological and evolutionary questions on the population level, because meaningful experiments can often be completed within a couple of weeks. Yet biological analysis of such populations is often extremely time consuming, owing to abundance estimation by counting, measuring body size, or determining the investment into sexual versus asexual reproduction. An automated system for sampling and analyzing experimental rotifer populations is described. It relies on image analysis of digital photographs taken from subsamples of the culture. The system works completely autonomously for up to several weeks and can sample up to 12 cultures at time intervals down to a few hours. It allows quantitative analysis of female population density at a precision equivalent to that of conventional methods (i.e., manual counts of samples fixed in Lugol solution), and it can also recognize males, which allows detecting temporal variation of sexual reproduction in such cultures. Another parameter that can be automatically measured with the image analysis system is female body size. This feature may be useful for studies of population productivity and/or in competition experiments with clones of different body size. In this article, I describe the basic setup of the system and tests on the efficiency of data collection, and show some example data sets on the population dynamics of different strains of the rotifer Brachionus calyciflorus.

中文翻译：

---

用于轮虫种群采样、计数和生物分析的自动化系统。


轮虫等世代时间短的浮游动物是研究种群水平上一般生态和进化问题的理想模型，因为有意义的实验通常可以在几周内完成。然而，由于通过计数、测量体型或确定有性繁殖与无性繁殖的投资来进行丰度估计，对这些种群的生物学分析通常非常耗时。描述了用于采样和分析实验轮虫种群的自动化系统。它依赖于对从培养物子样本中拍摄的数码照片进行图像分析。该系统完全自主工作长达数周，并且可以在短至几个小时的时间间隔内对多达 12 种培养物进行采样。它可以以与传统方法（即固定在卢戈溶液中的样品的手动计数）相当的精度对雌性种群密度进行定量分析，并且它还可以识别雄性，从而可以检测此类培养物中有性生殖的时间变化。图像分析系统可以自动测量的另一个参数是女性身体尺寸。此功能对于研究种群生产力和/或不同体型的克隆的竞争实验可能有用。在本文中，我描述了系统的基本设置和数据收集效率的测试，并展示了一些有关萼花轮虫不同品系种群动态的示例数据集。