What is used to anesthetize the flies?

Flies are commonly anesthetized using carbon dioxide (CO2) or by placing them in a cold environment, such as a freezer or on ice. CO2 is preferred in many laboratory settings because it induces rapid anesthesia without causing harm to the flies. Additionally, some researchers may also use volatile anesthetics like ether, though this is less common. These methods allow for the handling and manipulation of flies during experiments.