Flies were rendered germ-free (GF) following the protocol described in49 (link). GF flies were maintained on fly medium supplemented with antibiotics: kanamycin 50μg/mL (Sigma #K1377), ampicillin50μg/mL (Sigma #A0166), tetracyclin 10μg/mL (Sigma #T7660), erythromycin 5μg/mL (Sigma #E5389). Axenicity was confirmed by crushing the flies and plating the lysate on LB Agar (Carl Roth) and MRS Agar (Carl Roth) plates.