The post-embryonal development of arthropod species, including crustaceans and insects, is characterized by ecdysis or molting. This process defines growth stages and is controlled by a conserved neuroendocrine system. Each molting event is divided in several critical time points, such as pre-molt, molt and post-molt, and leaves the animals in a temporarily highly vulnerable state while their cuticle is re-hardening. The molting events occur in an immediate ecdysis sequence within a specific time window during the development. Each sub-stage takes only a short amount of time, which is generally in the order of minutes. To find these relatively short behavioral events, one needs to follow the entire post-embryonal development over several days. As the manual detection of the ecdysis sequence is time consuming and error prone, we designed a monitoring system to facilitate the continuous observation of the post-embryonal development of the fruit fly Drosophila melanogaster. Under constant environmental conditions we are able to observe the life cycle from the embryonic state to the adult, which takes about ten days in this species. Specific processing algorithms developed and implemented in Fiji and R allow us to determine unique behavioral events on an individual level - including egg hatching, ecdysis and pupation. In addition, we measured growth rates and activity patterns for individual larvae. Our newly created RPackage PEDtracker can predict critical developmental events and thus offers the possibility to perform automated screens that identify changes in various aspects of larval development. In conclusion, the PEDtracker system presented in this study represents the basis for automated real-time staging and analysis not only for the arthropod development.

中文翻译：

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PEDtracker：黑腹果蝇幼虫的自动分期方法

节肢动物物种（包括甲壳类和昆虫）的胚后发育以蜕皮或蜕皮为特征。这个过程定义了生长阶段，并由保守的神经内分泌系统控制。每次蜕皮事件都分为几个关键时间点，例如蜕皮前，蜕皮和蜕皮后，使动物的表皮重新变硬时处于暂时高度脆弱的状态。蜕皮事件在发育过程中的特定时间窗口内以立即蜕皮的顺序发生。每个子阶段只需要很短的时间，通常是几分钟。为了找到这些相对较短的行为事件，需要在几天内关注整个胚胎后的发展。由于手动检测蜕皮序列非常耗时且容易出错，果蝇。在恒定的环境条件下，我们能够观察到从胚胎状态到成年状态的生命周期，该生命周期大约需要十天。在Fiji和R中开发和实施的特定处理算法使我们能够确定个体水平上的独特行为事件-包括卵孵化，蜕皮和化脓。此外，我们测量了单个幼虫的生长速率和活动模式。我们新创建的RPackage PEDtracker可以预测关键的发育事件，因此提供了执行自动筛选以识别幼虫发育各个方面变化的可能性。总之，本研究中介绍的PEDtracker系统不仅为节肢动物的发育提供了自动化的实时分期和分析的基础。