Flies were raised on cornmeal-yeast-glucose-agar medium under a 12/12 h light/dark cycle (lights on at 06:00 hrs) at 25°C. Newly hatched to one day old flies were collected and transferred into a vial containing Kimwipe paper soaked with 100 mM glucose for one to two days as previously described (@book{Zhang B, Freema@book{Zhang B, Freeman MR_2010, title={Drosophila Neurobiology: A Laboratory Manual}, publisher={Cold Spring HarborLaboratory Press}, author={Zhang B, Freeman MR, Waddell S}, year={2010}}n MR_2010, title={Drosophila Neurobiology: A Laboratory Manual}, publisher={Cold Spring HarborLaboratory Press}, author={Zhang B, Freeman MR, Waddell S}, year={2010}}). Starved flies were kept in a vial containing Kimwipe paper soaked with Evian® water for 20 h before testing.