Simultaneous measurement of sleep and feeding in individual Drosophila

Drosophila is widely used for the dissection of genetic and neuronal mechanisms of behavior. Recently, flies have emerged as a model for investigating the regulation of feeding and sleep. Although typically studied in isolation, increasing evidence points to a fundamental connection between these behaviors. Thus, a system for measuring sleep and feeding simultaneously in a single integrated system is important for interpreting behavioral shifts of either state. Here, we describe the construction and use of the Activity Recording Capillary Feeder or CAFE (ARC), a machine-vision (automated image tracking)-based system for the integrated measurement of sleep and feeding in individual Drosophila. Flies feed on liquid food from a microcapillary, and consumption is measured by tracking the liquid meniscus over time. Sleep measurements are obtained from positional tracking of individual animals, and arousal threshold can be determined by vibrational stimulus response. Using this system, a single computer and experimenter can track diverse behaviors from up to 60 individual flies in a single integrated system. The ARC is efficiently assembled with minimal training, and each experiment can be run for up to ∼7 d, with a total setup and breakdown time of ∼2 h.