Homozygotes show partial lethality. Homozygous males and females are fertile.
Homozygous Df(2R)mir-309-6Δ1 animals show a modest reduction in viability to adulthood. Homozygous Df(2R)mir-309-6Δ1 mutants show little or no reduction in the completion of embryogenesis compared to controls.
Homozygotes complete embryogenesis with no apparent defects in patterning, but approximately 20% die as larvae at different larval stages. Some animals stop growing at the size of second instar larvae and arrest at this stage for a few days before dying. Approximately 80% of homozygotes survive to adulthood and are viable and fertile. The mutant animals show a developmental delay during larval stages.