Eip75BΔ51/Eip75BΔ51 mutant mushroom body neuron clones fail to fully innervate the adult gamma lobe during regrowth at metamorphosis, and also display a weak pruning defect, but there is no defect in initial extension of these neurons, as compared to wild type.
Almost all Eip75BA81/Eip75BΔ51 mutant second instar larvae fail to molt and develop to later stages. Feeding ecdysone to these second instar larvae rescues 50% of them to the pupal stage.
Eip75BΔ51 homozygotes remain as first instar larvae for over a week before dying without any detectable morphological abnormalities. Approximately 33% of Eip75B1/Eip75BΔ51 animals die as pharate adults, with normal adult pigmentation and fully developed appendages. The animals eclose and are severely uncoordinated, displaying difficulty in walking and an inability to fly. These animals die within a week following eclosion, but appear morphologically normal with the exception of black spots that cover about one quarter of the surface of the eye. Eip75BΔ1/Eip75BΔ51 animals are viable and fertile, with no detectable phenotypes. Subsets of first and second instar Eip75BA81/Eip75BΔ51 larvae never molt to the next instar, surviving for up to a week before dying. Those that molt do so up to 12 hr late, while some die at the molt. These animals often have malformed mouthhooks or two sets of mouthhooks. Among the remainder, significant lethality occurs in the 3rd instar, and pre-pupal stages, with the rest dying as pharate adults that, while failing to eclose, have no obvious morphological defects. Approximately 20% of Eip75BA81/Eip75BΔ51 second instar larvae fail to undergo the 2nd to 3rd instar molt but nevertheless pupariate, despite maintaining 2nd instar morphology as judged by mouthhooks and anterior spiracles. This pupariation takes place approximately 88 hours after the 1st to 2nd instar molt. About 20% of the L2 prepupae (n = 85) develop to the pupal stage as evidenced by head eversion and leg and wing extension. Eip75BA81/Eip75BΔ51 second instar larvae have a reduced ecdysteroid titer, and their molting defects can be rescued by treatment with ecdysteroids.