Homozygous adults show an enhanced olfactory response to ethyl acetate compared to wild-type flies. The amplitude of the electroantennogram (EAG) of homozygous flies obtained in response to ethyl acetate shows no significant difference to that of wild-type flies. The voltage change of the EAG of homozygotes is retarded compared to that of wild-type flies, and there is a tendency for retarded recovery of the electrical response after odorant stimulation.