ac itation ▁mechanism ▁( without ▁removal ▁of ▁first ▁male ▁s perm ) ▁which ▁takes ▁effect ▁before ▁fert il ization ▁occurs . ▁The ▁delay ▁in ▁effect iveness ▁of ▁the ▁in cap ac itation ▁mechanism ▁is ▁believed ▁to ▁be ▁a ▁protect ive ▁mechanism ▁that ▁prevents ▁a ▁male ▁fly ▁from ▁in cap ac it ating ▁his ▁own ▁s perm ▁should ▁he ▁mate ▁with ▁the ▁same ▁female ▁fly ▁repet it ively . ▁S ens ory ▁neur ons ▁in ▁the ▁u ter us ▁of ▁female ▁D . ▁mel an og aster ▁respond ▁to ▁a ▁male ▁protein , ▁sex ▁pe pt ide , ▁which ▁is ▁found ▁in ▁sem en . ▁This ▁protein ▁makes ▁the ▁female ▁rel uct ant ▁to ▁cop ulate ▁for ▁about ▁ 1 0 ▁days ▁after ▁ins em ination . ▁The ▁signal ▁path way ▁leading ▁to ▁this ▁change ▁in ▁behavior ▁has ▁been ▁determined . ▁The ▁signal ▁is ▁sent ▁to ▁a ▁brain ▁region ▁that ▁is ▁a ▁hom olog ▁of ▁the ▁hypoth al am us ▁and ▁the ▁hypoth al am us ▁then ▁controls ▁sexual ▁behavior ▁and ▁desire . ▁Gon ad otrop ic ▁h orm ones ▁in ▁D ros oph ila ▁maintain ▁home ost asis ▁and ▁govern ▁re product ive ▁output ▁via ▁a ▁cy clic ▁inter rel ations hip , ▁not ▁unlike ▁the ▁m amm al ian ▁est r ous ▁cycle . ▁Sex ▁pe pt ide ▁pert ur bs ▁this ▁home ost asis ▁and ▁dram atically ▁sh ifts ▁the ▁end ocr ine ▁state ▁of ▁the ▁female ▁by ▁inc iting ▁ju ven ile ▁h orm one ▁synth esis ▁in ▁the ▁cor