Starvation procedure
Newly hatched to one day old flies were collected and transferred to fresh food vials. The following day, between 16:00 and 19:00 hrs, 20 to 30 flies of mixed were transferred into starvation vials (68 ml, Greiner bio-one, Frickenhausen, Germany) by a fly aspirator. The starvation vial contained a cotton pad moistened with 2.5 to 3 ml of Evian® water. If not otherwise indicated, starvation was performed at 25°C and 60% relative humidity and lasted for 20 h.