FLEX: Flight Exercise Training Protocol for the Fruit Fly Drosophila.

Drosophila has recently become a popular model for studying obesity and related disorders. While it's relatively easy to induce metabolic disorders in Drosophila using specific diets, creating an exercise model for the flies is more challenging. Existing methods, such as the Power Tower and Treadwheel, utilize shaking or rotating vials to induce the flies to climb, leveraging their negative geotaxis response. However, continuous climbing for long periods is unnatural for the flies and can lead to exercise-related injuries and mortalities. This paper introduces a new exercise protocol that leverages the fly's natural ability to fly, offering a more natural, physiological, and injury-free exercise approach. The experiments show that a 5-day flight exercise regimen increases the fly's bioenergetic capacity and counteracts the adverse effects of a Western diet (WD), improving climbing behavior and reducing WD-associated mortality. This protocol enables the simultaneous training of a large number of flies to study the interaction between exercise and various factors, including diet, drugs, aging, and genetics. Together, this method can complement existing methods for studying the effects of exercise on fly physiology and behavior.