34% of fru^AJ96u3/fru^w12 animals die at midpupal stages (P5-P13). 56% can emerge if dissected from the pupal case. 15.0% of fru^w12/fru^sat15 embryos have abnormal Fas2-positive fascicles and 16.3% have defects in the distribution and pattern of BP102-positive axons in the central nervous system. Axonal outgrowth of the dMP2 and vMP2 neurons can be delayed in these embryos, while in some cases the growth cone appears to initiate growth in an abnormal direction. 23.4% of fru^w12/Df(3R)fru^w24 embryos have abnormal Fas2-positive fascicles and 23.9% have defects in the distribution and pattern of BP102-positive axons in the central nervous system. 20.5% of fru^w12/fru^P14 embryos have abnormal Fas2-positive fascicles in the central nervous system. The developing medial Fas2-positive fascicle is indistinct in stage 13 embryos and the aCC neuron sometimes either joins the ascending pCC axon or grows posteriorly (instead of extending peripherally as occurs in wild-type embryos). 14.4% of fru^w12/fru^AJ96u3 embryos have abnormal Fas2-positive fascicles in the central nervous system. The average number of repo-positive glial cells is not different from wild type in fru^w12/fru^sat15 embryos, although the pattern of the repo-positive glial cells is slightly abnormal. The Fas2-positive and BP102-positive axon tracts in the central nervous system are defective in virtually all fru^w12/fru^sat15 embryos which are expressing fru^{MA.Scer\UAS.cSa}, fru^{MB.Scer\UAS.cSa} or fru^{MC.Scer\UAS.cSa} under the control of Scer\GAL4^sca-537.4.

1-2% fru^w12/fru^w27 adult escapers are seen. 2% fru^w12/fru^sat15 adult escapers are seen. Male-female courtship as measured by courtship index (CI) or wing extension index (WEI) is almost completely abolished in fru^w12/fru^4-40 or fru^w12/fru^w27 males. Male-female courtship as measured by wing extension index (WEI) is almost completely abolished in fru^0-1/fru^w12 males. fru¹/fru^w12 males show significantly more male-male courtship and less frequent male-female courtship than wild-type males. fru^w12/fru¹, fru^w12/fru^0-1, fru^w12/fru³ or fru^w12/fru⁴ males show substantial chaining. Heterozygous males generate a normal courtship song except that the width of the fast-Fournier transform is smaller than in wild-type males. fru^w12/fru^4-40 and fru^w12/fru^M5 males do not produce a courtship song even though they show a small amount of wing extension. fru¹/fru^w12 males have a courtship song with longer interpulse intervals, but essentially normal intrapulse frequencies, cycles per pulse and width of the fast-Fourier transform compared to control males. fru^w12/fru^w27 animals are able to emerge if dissected from the pupal case. These animals perform posteclosion behaviours such as wing and proboscis expansion but are unable to fully extend their wings, which project from the body at a 70-90^o angle. The tibial segment may be bent. Leg joint defects and duplicated bristles are seen. fru^w12/fru^P14 or fru^w12/fru^sat15 adults that have been dissected from the pupal case show minor external defects, such as uninflated wings, wings held at a 70-90^o angle to the body, leg joint defects and duplicated bristles. fru^w12/Df(3R)fru^w24 adults that have been dissected from the pupal case show minor external defects, such as leg joint defects and duplicated bristles. Abdominal motorneurons of fru^w12/fru^w27 animals produce fewer lateral terminal arborisations as they terminate on lateral muscles compared to wild type.

fru^w27/fru^w12 mutants are nearly lethal during late pupal stages.

Transheterozygotes with Df(3R)fru^w24 or fru^w27 are lethal, 2% fru^w12/fru^w27 transheterozygotes survive to adulthood. fru³/fru^w12, fru⁴/fru^w12 and fru⁴/Df(3R)Cha^M5 males barely court at all but show normal locomotor activity. Mutant combination shows some male-male chaining. Early and late steps of courtship are disrupted.