Imprecise excision of the P{wAR} insertion causing an internal deletion of the element.
Heterozygotes develop to pharate adults that exhibit an 'unkempt' phenotype: small rough eyes, held out wings and crossed scutellar bristles. Heterozygotes with unkOR20 also exhibit the 'unkempt' cuticular defects: roughened eyes, splayed wings and crossed scutellar bristles.