Poxn^ΔM22-B5/Poxn^ΔM22-B5 females display a loss of aversion to oviposit on polyamine-rich substrate (plain, sugar-free 1% agarose supplemented with either putrescine or cadaverine) versus non-supplemented substrate, in contrast to wild type flies, instead showing no preference for laying on either substrate, and additionally displaying a significant reduction in egg-laying during the first 3 hours of this assay as compared to wild type; however, these flies still show a preference for spending time on the polyamine-rich substrate, similar to wild type.

Poxn^ΔM22-B5 mutant male flies expressing Poxn^ΔXBs lack gustatory neurons in the labelum, legs and wing margins. The flies are generally healthy. Male flies exposed to other males that have been engineered to produce female pheromones (by expressing tra^Scer\UAS.cFa under the control of Scer\GAL4^OK72) do not show the increases in starvation resistance, triaylglyceride (TAG) amount and lifespan that are seen when they are exposed to wild type males.

Poxn^ΔM22-B5 mutant flies expressing Poxn^Full lack gustatory neurons in the labelum. As in wild type, males exposed to other males that produce the normal male pheromones exhibit increased starvation resistance, increased triacylglyceride (TAG) amounts and increased lifespan compared with males engineered to produce female pheromones.

In a two-choice assay, mutant flies develop a preference to glucose over plain agar after 18 hours of food deprivation, but fail to consume glucose mixed with phlorizin (a drug that blocks the transport of glucose from the intestinal lumen into the blood in mammals). The mutant flies are able to distinguish fructose mixed with phlorizin from plain agar in this assay.

Poxn^ΔM22-B5 mutant flies exhibit a lack of gustatory water reception.

Homozygous Poxn^ΔM22-B5 mutant females show reduced egg-laying preference when compared to wild-type.

Positional aversion to acetic acid is reduced in homozygous Poxn^ΔM22-B5 females.

In the dark in the presence of a virgin female, Poxn^ΔM22-B5/Poxn^ΔM22-B5 males rescued by simultaneously carrying both Poxn^ΔXBs and Poxn^ΔPBs scan for the female by spreading their wings and scanning in a zigzag course, as do wild-type males in this courtship assay.

Only half of Poxn^ΔM22-B5/Poxn^ΔM22-B5 males rescued by simultaneously carrying both Poxn^ΔXBs and Poxn^ΔPBs initiate courtship in the dark, but their latency does not differ significantly from that of wild type. After courtship initiation the mutant males court females with the same vigor as do wild-type males.

Poxn^ΔM22-B5/Poxn^ΔM22-B5 males rescued by simultaneously carrying both Poxn^ΔXBs and Poxn^ΔPBs court with the same intensity as wild-type males in daylight.

Poxn^ΔM22-B5/Poxn^ΔM22-B5 males rescued by simultaneously carrying both Poxn^ΔXBs and Poxn^ΔPBs show no preference for courtship initiation towards decapitated females or males in the dark, with only half of them initiating courtship. These males court decapitated females and males with indistinguishable high courtship vigor indexes.

Poxn^ΔM22-B5/Poxn^ΔM22-B5 males rescued by simultaneously carrying both Poxn^ΔXBs and Poxn^ΔPBs show a significantly higher courtship vigor index towards intact or dewinged males in the dark compared to control wild-type males facing intact males.

Poxn^ΔM22-B5/Poxn^ΔM22-B5 males rescued by simultaneously carrying both Poxn^ΔXBs and Poxn^ΔPBs are clearly able to distinguish between decapitated males and females in daylight in a courtship assay.

Poxn^ΔM22-B5/Poxn^ΔM22-B5 males rescued by simultaneously carrying both Poxn^ΔXBs and Poxn^ΔPBs show courtship chains when groups of mature, but sexually naive, males are placed together in a petri dish.

Poxn^ΔM22-B5/Df(2R)WMG flies lack chemosensory bristles. Homozygous flies show defects in all taste bristles on the wings, legs and labellum. All taste bristles on the anterior wing margin are transformed into mechanosensory bristles. The transformed dorsal bristles no longer form a second posterior row, but are interspersed with the anterior row of mechanosensory bristles, forming a single dorsal row. The transformed bristles are longer and thicker than wild-type mechanosensory bristles. The taste bristles on the leg are transformed into bracted mechanosensory bristles, most of which are indistinguishable in morphology from wild-type mechanosensory bristles, or are occasionally lost. On the tibia, some transformed bristles are longer and thicker than the surrounding mechanosensory bristles. On the labellum, the number of taste bristles is unchanged, but their shafts are longer than normal, have pointed tips like those of mechanosensory bristles and they are often bent or kinked. Under daylight conditions, 2/3 of Poxn^ΔM22-B5 males do not initiate courtship in single choice experiments within 15 minutes under standard conditions, while the remaining 1/3 court females very weakly, but do proceed through the entire courting sequence. Although these males do attempt to copulate by bending their abdomen, no copulation has been observed. Poxn^ΔM22-B5 males show no courtship behaviour under red light. Poxn^ΔM22-B5 males have no penis, although the penis apodeme and protractor muscle are still present. The posterior lobes are degenerate and the claspers have slightly abnormal bristle patterns. The testes are well developed with accessory glands, ejaculatory duct, sperm pump and motile sperm. Homozygous flies have defects in the wing hinge. Homozygous adults cannot fly properly, although males can extend and vibrate the wing during the initial steps of courting. The projection pattern of Poxn-expressing neurons in the brain is altered in Poxn^ΔM22-B5 flies.