General morphology of the mutant larvae and adults is normal. Most homozygotes are able to survive to adulthood if competition with heterozygous siblings is eliminated. However, competition from heterozygous siblings results in the death of homozygous animals (85-100% lethality) before adulthood. Homozygous larvae have a severely compromised ability to roll over from an inverted position; the time required to right themselves is significantly longer than control larvae. Homozygous adults cannot fly, although they walk normally and energetically on a level surface. The jump response is intact and robust, but attempts at flight result in the flies flipping themselves onto their backs, where continued efforts to fly are shown by the adults flapping their wings at high speeds (this only results in the flies spinning frantically in circles). Adults that become inverted are rarely able to right themselves, despite what appears to be an intense effort to roll over. Only 12-36% of adults are able to roll over after 60 seconds, in contrast to wild-type which roll over immediately, almost always in less than one second. No alterations in brain morphology (including the superior lateral protocerebrum and regions associated with the mushroom bodies) are seen in mutant adults.