Tools　that　allow　inducible　and　reversible　depletion　of　target　proteins　are　critical　for　biological　studies.　The　plant-derived　auxin-inducible　degradation　system　(AID)　enables　the　degradation　of　target　proteins　tagged　with　the　AID　motif.　This　system　has　been　recently　employed　in　mammalian　cells　as　well　as　in　Caenorhabditis　elegans　and　Drosophila.　To　test　the　utility　of　the　AID　approach　in　the　nervous　system,　we　used　circadian　locomotor　rhythms　as　a　model　and　applied　the　AID　method　to　temporally　and　spatially　degrade　PERIOD　(PER),　a　critical　pacemaker　protein　in　Drosophila.　We　found　that　the　period　locus　can　be　efficiently　tagged　with　the　AID　motif　by　CRISPR/Cas9-based　genome　editing　without　disrupting　PER　function.　Moreover,　we　demonstrated　that　the　AID　system　could　be　used　to　induce　rapid　and　efficient　protein　degradation　in　the　nervous　system　as　shown　by　effects　on　circadian　and　sleep　behaviors.　Furthermore,　the　protein　degradation　by　AID　was　rapidly　reversible　after　auxin　removal.　Together,　our　results　show　that　the　AID　system　provides　a　powerful　tool　for　behavior　studies　in　Drosophila.　©　2018　Federation　of　European　Biochemical　Societies