Homozygotes show loss of sternites and sternal bristles and expansion of the pleura in the abdomen.
Eyes of flies transheterozygous for pan13/panER1 and raised at non-permissive temperature show normal polarity although some ommatidia contain extra photoreceptors.
Shows a strong genetic interaction with armS8 and armS9, resulting in adult phenotypes characteristic of reduced wg activity. Homozygotes are viable at 18oC, but die during the larval or pupal stages if raised at 29oC. At intermediate temperatures, homozygotes show defects characteristic of reduced wg activity; antennae are truncated, the dorso-ventral polarity of the leg pattern is lost, wings show notching, sternite bristles are lost and sternite tissue is replaced by pleura.