The addition of L-DOPA to food ingested by ple² heterozygotes significantly improves food intake.

Flies expressing ple^FS.Scer\UAS in a ple² background exhibit reduced walking speed compared to wild-type. Similarly, they cover a shorter distance in a 15 minute period. These flies also respond poorly to mechanical shock (that induces climbing in wild-type flies).

Flies expressing ple^FS.Scer\UAS in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) are overall less active and possibly sleep more frequently than controls. In addition, sleeping ple^FS.Scer\UAS; ple² flies respond less frequently to mild and moderate mechanical stimuli, whereas response to strong stimuli is comparable to controls.

Flies expressing ple^FS.Scer\UAS in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) show no response to 3-iodotyrosine (whereas controls exhibit decreased activity). In contrast, caffeine is found to decrease resting periods in these flies.

Flies expressing ple^FS.Scer\UAS in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) do not show any avoidance to shock-associated odors indicating impaired adversive olfactory learning. Interestingly, these flies show an inverse tendency to choose the shock-associated odor during testing. This effect is significant 2 hours after training.

Treatment of flies expressing ple^FS.Scer\UAS in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) with the DA precursor L-DOPA significantly improves their negative geotaxis behavior and olfactory learning.

Flies expressing ple^FS.Scer\UAS in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) show no significant response to sucrose. The proboscis extension reflex appears normal in these mutants however, indicating that sugar perception and reflex appetitive reactions are preserved. Quantification of food intake suggests that these flies eat one-third as much as controls, demonstrating that they are markedly hypophagic. The addition of L-DOPA significantly improves this phenotype.

Flies expressing ple^FS.Scer\UAS in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) appear to show a lack of phototaxis despite displaying normal electroretinograms and optomotor responses.

Flies expressing ple^Scer\UAS.cFa or ple^FS.Scer\UAS in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) display slightly less accurate visual orientation than wild-type. Similarly, using the detour paradigm, both ple^Scer\UAS.cFa; ple² and ple^FS.Scer\UAS; ple² flies demonstrate a roughly wild-type spatial orientation memory.

ple² flies expressing either ple^Scer\UAS.cFa or ple^FS.Scer\UAS under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL exhibit normal adult life expectancy.

Flies expressing ple^Scer\UAS.cFa in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) demonstrate associative memory similar to wild-type, indicating normal olfactory learning.

Flies expressing ple^Scer\UAS.cFa in a ple² background (under the control of both Scer\GAL4^ple.PF and Scer\GAL4^Ddc.PL) demonstrate partial rescue of ple² phototactic behavior.

Heterozygous embryos have ectopically migrating tracheal branches and tracheal cells. The dorsal trunk is often convoluted.

Heterozygotes have normal locomotor activity at 25^oC.

ple^+t8 rescues mutant embryos to viable adults. Some adults die attempting to free themselves from the pupal case, the greatest lethality occurs during the pharate adult stage. Adults that do eclose are paler than their ple⁺ siblings and they appear weaker in their movements with a tendency to drown in the food medium. Rescued larvae are normal in their response to both light and NaCl.