Expression of eyg^{Scer\UAS.T:Hsim\VP16} under the control of Scer\GAL4^CD abolishes head and eye development. Thorax development is not affected in these animals.

Normal head and eye development is observed when eyg^{Scer\UAS.T:Hsim\VP16} is expressed under the control of Scer\GAL4^EX, Scer\GAL4^F1, or Scer\GAL4^XS. Expression under the combined control of Scer\GAL4^EX and Scer\GAL4^XS results in normal sized third instar larval stage eye discs.

Expression of eyg^{Scer\UAS.T:Hsim\VP16} under the temporally-restricted control of Scer\GAL4^CD during 24-48, 36-60 or 48-72 AEL (expression restricted by Scer\GAL80^ts.αTub84B throughout other stages of development) causes significant eye reduction. Expression during stage 0-24 and 60-84 AEL results in minor head defects.

Expression of the eyg^{Scer\UAS.T:Hsim\VP16} transgene, under the control of Scer\GAL4^dpp.blk1, causes a reduction of the endogenous eye and does not induce an extra ventral eye. Expression of eyg^{Scer\UAS.T:Hsim\VP16}, under the control of Scer\GAL4^eyg-22-2, causes a headless phenotype and a grooved thorax. Expression of eyg^{Scer\UAS.T:Hsim\VP16} in a eyg^22-2/eyg^M3-12 background causes a headless phenotype with 100% penetrance.