Ommatidia sometimes contain an extra rhabdomere and attached cell body located next to photoreceptor R7 in mutant adults. Almost 100% of mutant pupal ommatidia contain an extra photoreceptor (assayed by elav staining). The nucleus of one photoreceptor (most likely R7) is pushed towards the centre of the ommatidium in these pupal ommatidia.
In pupae containing homozygous clones in the eye, all mosaic ommatidia containing four or more wild-type photoreceptors have the normal number of eight photoreceptors, while all mosaic ommatidia containing fewer than four wild-type photoreceptors have an extra photoreceptor. There is no discernible pattern in the arrangement of wild-type photoreceptors within the ommatidia that contain an extra photoreceptor.
7% of Dip31 mutant embryos fail to hatch and exhibit D/V patterning defects.
Dip31 mutants show 55% lethality one month after bacterial infection with a 1:1 mixture of M. luteus (Gram-positive) and E. coli (Gram-negative), compared to 10% in wild-type. Wild-type and Dip31 mutant adults are equally sensitive to fungal infection (B. brassiana), with both showing 55-70% lethality after 30 days. Dip31 mutant larvae show a reduced eclosion rate following injection with M. luteus and E. coli.