Long-term in vivo imaging of Drosophila larvae

The Drosophila larva has been used to investigate many processes in cell biology, including morphogenesis, physiology and responses to drugs and new therapeutic compounds. Despite its enormous potential as a model system, longer-term live imaging has been technically challenging because of a lack of efficient methods for immobilizing larvae for extended periods. We describe here a simple procedure for anesthetization and uninterrupted long-term in vivo imaging of the epidermis and other larval organs, including gut, imaginal discs, neurons, fat body, tracheae, muscles and hemocytes, for up to 8 h. We also include a procedure for probing cell properties by laser ablation. We provide a survey of the effects of different anesthetics, demonstrating that short exposure to diethyl ether is the most effective for long-term immobilization of larvae. This protocol does not require specific expertise beyond basic Drosophila genetics and husbandry, and confocal microscopy. It enables high-resolution studies of many systemic and subcellular processes in larvae.