speck^lo homozygous adults exhibit low levels of activity while awake and increased recovery sleep the next day after overnight mechanical sleep deprivation.

Mutant third instar larvae are capable of synaptic homeostasis at the neuromuscular junction, as indicated by an increase in quantal content in the presence of the glutamate receptor antagonist philanthotoxin-433 (10μM).

Socially enriched Dat^lo/Df(2R)Px2 do not show a change in sleep when exposed to a period of social isolation, in contrast to control socially enriched flies which show a decrease in sleep requirement after exposure to social isolation.

Homozygous flies do not differ from wild-type flies in the percentage and distribution of rest and waking and show normal amounts and patterns of activity. However, after 12 hours of rest deprivation during the dark period, homozygous flies display a rest rebound that is greater than in rest-deprived control flies. Dat^lo/Df(2R)Px1 flies do not differ from Dat^lo homozygotes or wild-type flies in the percentage and circadian distribution of rest and waking. Dat^lo/Df(2R)Px1 flies show not only an increased rest rebound during the first 6 hours of recovery (after rest deprivation) relative to wild-type flies, but also a persistent rebound during the second 6 hours of recovery.

Dopamine acetyltransferase activity low and relative thermolabile. Dat⁺/Dat^lo activity level intermediate between those of the two homozygous genotypes.