Under control conditions, fru^F/fru^4-40 and fru^F/fru^4-40 transheterozygotes do not show significant changes in mitotic index in the female and male adult posterior midgut, as compared to controls.

fru^4-40/fru^P1.LexA adult males do not have the male-specific ventrolateral protocerebrum projection neuron 1; there is no effect on its absence from the female.

In fru^F/fru^4-40 males the post-embryonic Ilp7 neurons in the posterior adult ventral nerve cord are feminised; the normally female-specific ventral subset of 3-4 post-embryonic Ilp7 neurons is present adjacent to the usual embryonic Ilp7 neurons. The dorsal cluster of post-embryonic Ilp7 neurons seen in both males and females is retained but, as in females, no longer express serotonin.

In fru^M/fru^4-40 females the post-embryonic Ilp7 neurons in the posterior adult ventral nerve cord are partially masculinised; the ventral cluster of female-specific Ilp7 neurons are still present but, as in males, the shared dorsal cluster neurons express serotonin.

fru¹/fru^4-40 D. melanogaster males court conspecific D. melanogaster males. They also court D. simulans and D. yakuba males, but do not court D. virilis males.

fru^4-40/fru^sat15 males do not court target D. melanogaster females. They also do not court D. simulans, D. virilis or D. yakuba females.

In addition to courting conspecific D. melanogaster females, fru¹/fru^4-40 D. melanogaster males court D. simulans, D. virilis and D. yakuba females.

Midline crossing by foreleg gustatory receptor neuron (GRN) axons is nearly absent in fru^P1.LexA/fru^4-40 XY animals.

Flies transheterozygous for fru^ΔC and fru^4-40 exhibit approximately 21% fertility compared to wild-type. They do not experience reduced viability.

The normally male specific 'muscle of lawrence' is absent in fru^F/fru^4-40 males, but is ectopically present in fru^M/fru^4-40 or fru^Δtra/fru^4-40females. fru³/fru^4-40 and fru⁴/fru^4-40 males exhibit very little courtship behaviour towards females, while fru^F/fru^4-40 males fail to court females. Males of all of these genotypes show significant increases in courtship behaviour towards wild-type males and form all male mating chains among themselves. In contrast, fru^M/fru^4-40 and fru^Δtra/fru^4-40 males exhibit normal overall levels of courtship behaviour towards females (courtship index) and show a significant competitive advantage in competition with wild-type males to mate with a wild-type virgin female. This may be mainly due to a significant decrease in courtship latency seen in these males. These flies who not significant increases in courtship behaviour towards wild-type males compared to wild-type and do not form all male mating chains. fru^M/fru^4-40 or fru^Δtra/fru^4-40 females court wild-type females, with courtship indices over 40% in single-pair assays. They also form courtship chains with other females of their own genotype (chaining indices >40%). These females perform all steps in the male courtship ritual apart from copulation, which is anatomically impossible, and abdominal bending in attempt to copulate, which may be inhibited by the much larger abdomen of females. However, the proportion of time spent in different parts of the courtship ritual differs form control (fru^C/fru^4-40) males: they spend significantly more time tapping and less time licking, overall courting time is reduced but initiation of courtship is just as rapid. Unlike control females, these females also court males. Courtship of males by fru^M/fru^4-40 or fru^Δtra/fru^4-40 females is significantly enhanced if the males are tra^Scer\UAS.cFa; Scer\GAL4^oeC.

fru^sat15/fru^4-40 and fru^P14/fru^4-40 embryos have normal Fas2-positive and BP102-positive axon tracts in the central nervous system.

24% of fru^0-1/fru^4-40 males are fertile. Male-female courtship as measured by courtship index (CI) or wing extension index (WEI) is almost completely abolished in fru^w27/fru^4-40, fru^sat15/fru^4-40, fru^P14/fru^4-40, fru^w9/fru^4-40 or fru^w12/fru^4-40 males. Male-female courtship as measured by courtship index (CI) or wing extension index (WEI) as measured by WEI is almost completely abolished in fru³/fru^4-40 or fru⁴/fru^4-40 males. fru³/fru^4-40 and fru⁴/fru^4-40 males show significant male-male courtship as measured by CI. fru¹/fru^4-40 males show significantly more male-male courtship and less frequent male-female courtship than wild-type males. fru^4-40/fru¹, fru^4-40/fru^0-1, fru^4-40/fru³, fru^4-40/fru^w9, fru^4-40/fru^w27, fru^4-40/fru^sat15 or fru^4-40/fru⁴ males show substantial chaining. fru³/fru^4-40, fru⁴/fru^4-40, fru^w12/fru^4-40 and fru^w27/fru^4-40 males do not produce a courtship song even though they show a small amount of wing extension. fru¹/fru^4-40 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^AJ96u3/fru^4-40 is a non-enhancer of abnormal courtship behavior | female phenotype of retn^z2-428/retn⁰⁵⁰⁹⁶

fru^sat15/fru^4-40 is a non-enhancer of abnormal courtship behavior | female phenotype of retn^z2-428/retn⁰⁵⁰⁹⁶

fru^sat15/fru^4-40 is a non-suppressor of abnormal courtship behavior | female phenotype of retn^z2-428/retn⁰⁵⁰⁹⁶

fru^AJ96u3/fru^4-40 is a non-suppressor of abnormal courtship behavior | female phenotype of retn^z2-428/retn⁰⁵⁰⁹⁶