cpo^EG1/cpo² flies have behavioural abnormalities in phototaxis, geotaxis, flight and recovery from ether. The flies are sluggish and show defects in mating vigour. cpo^EG1/cpo² flies are more sensitive to seizures induced by a high frequency stimulus than wild-type flies; the mean seizure threshold is reduced compared to wild-type flies, to 13.3 +/- 4.8 V. The recovery period following seizure for cpo^EG1/cpo² flies is 98.6 +/- 15.0 seconds respectively, which is considerably longer than the recovery period of wild-type flies. The firing threshold of the giant fiber in cpo²/+ and cpo^EG1/cpo² flies is not significantly different from wild type. The giant fiber-tergotrochanteral muscle (GF-TTM) response is abnormal cpo^EG1/cpo² flies; the wild-type short latency response is replaced by a longer latency response that cannot follow even moderate frequencies of stimulation. The giant fiber-dorsal longitudinal muscle (GF-DLM) response in cpo^EG1/cpo² animals is normal in latency but impaired in following frequency.

Behavioural defects in the adult.

Behavioural defects in phototaxis, geotaxis, flight response and recovery from ether anaesthesia are seen in homozygotes and in transheterozygotes with either cpo^l1 or cpo^l2. Behavioural defects in phototaxis and recovery from ether anaesthesia are seen in transheterozygotes with cpo¹.