Poxn⁷⁰ adults exhibit decreased repulsion to HCl and tartaric acid, assessed in proboscis extension response assays.

Poxn⁷⁰ mutants lack chemosensory sensilla in the anterior wing margin and, instead, present sensilla that appear larger than their neighbors.

Poxn⁷⁰ homozygous adults given a choice between sucrose solution and water have significantly reduced sucrose, but not water, consumption, compared to heterozygous controls.

The thoracic segments lack the lateral kolbchen (lk) in mutant first instar larvae and an extra papilla-like structure forms in a more ventral

position, just dorsal to p4. The ventral kolbchen (vk) is also missing

and an extra papilla forms more dorsally, adjacent to p3. In the abdominal

segments the central p-es organ p6 is absent and a new hair forms near

the position of h1, while the dorsal p-es organ h3 is substituted by

a papilla-like structure at a position dorsal to h2.

The les3 neurons are substituted by a single neuron with a solely extending

dendrite in mutant embryos. The v'es3 neurons are also missing and

instead a single neuron and an accompanying md neuron are arranged

just below the lateral cluster. The des2 neurons are missing in the

dorsal cluster in the abdominal segments. Instead, a single neuron

forms dorsal to lch5. The v'es2 neurons are substituted by a single

es neuron accompanied by an md neuron at a position near that of the

lesA and ldaA neurons. The axons of the neurons associated with the

transformed external sensory structures fasciculate with those of the

nearest neurons rather than retracing the pathway that p-es neurons

would normally have followed.

The external structures of es organs in second and third instar mutant

larvae are different from those in mutant first instar larvae. In

addition to the transformation of p-es into m-es organs, all hairs

disappear and are replaced by papilla-like structures in the thoracic

and abdominal segments. The positions of the organs do not change.

The tarsus of the mesothoracic leg is reduced to three segments in

mutant flies. This is due to a fusion rather than a loss of segments.

The intermediate segment of the mutant tarsus (T2/3) appears to be

a fusion of the 2nd and 3rd tarsal segments of wild-type flies; it

includes the bristle patterns of the 2nd and 3rd tarsal segments of

wild-type flies and in many cases an incomplete ball and socket is

seen where the prospective joint should have formed. The intersegmental

membrane is never seen on the ventral side. The distal segment of

the mutant tarsus (T4/5) appears to be a fusion of the 4th and 5th

tarsal segments of wild-type flies; it has a pattern of bristles corresponding

to the juxtaposition of the patterns of the normal 4th and 5th segments.

No incomplete joints are seen in the T4/5 tarsus. The mutant T2/3

segment is reduced in length by 34% relative to the combined length

of wild-type tarsal segments T2 and T3, while the mutant T4/5 segment

is reduced in length by 56% relative to the combined length of wild-type

tarsal segments T4 and T5. The mutant tarsal segment T1 shows a 20%

reduction in length compared to wild type. The size and patterning

around the circumference of the tarsus appears normal. Other leg segments

are unaffected.

The joint between the basal cylinder and the arista does not form properly

in mutant antennae. Other antennal structures are not affected.

The proximal part of the radius is thick and shortened in the anterior

part of the mutant wing hinge. Posteriorly, the first vannal vein

and the postcubitus are fused and the region anterior to the alula

is reduced and misformed.

The number of recurved bristles on the anterior wing margin and the mesothoracic tibia is reduced in Poxn⁷⁰/Df(2R)WMG flies. Poxn⁷⁰/Df(2R)KL32 flies have the normal number of recurved bristles on the anterior wing margin, but a reduced number of recurved bristles on the mesothoracic tibia. The recurved shafts of the chemosensory bristles in hemizygous and homozygous flies are transformed into straight shafts that are similar to, but larger than, those of the mechanosensory bristles of wild-type flies. In homozygotes and hemizygotes, single neurons are observed where clusters of neurons which innervate chemosensory bristles are observed in wild-type flies. The sensory mother cells of the chemosensory bristles follow a lineage appropriate for mechanosensory bristles in hemizygous flies. Homozygous and hemizygous larvae lack the kolbchen and larval polyinnervated external sensory organs.