The expression of sbm^KK101306 under the control of Scer\GAL4^repo.PU (in combination with Dicer-2, for an efficient RNAi) leads to a significant delay to pupation, increased larval weight, increased food intake/larval weight, increased third instar larval fat body cell size, decreased wing disc area, decreased third instar brain lobe volume associated with delayed brain development, decreased brain cell replication and decreased number of glial cells, increased pupal volume, increased adult male weight, increased wing area and decreased density of wing hairs, but does not have significant effects on the L2 molting timing or on the size of the larval ring gland. Expression under the control of Scer\GAL4^αTub84B.PL similarly leads to an an increase in larval weight and a delay to pupation (driver alone) or to an extended third larval instar in which larvae remain in the feeding substrate for up to 10 days and never commence wandering or pupation (driver in combination with Dicer-2 expression). A delay to pupation is also observed if sbm^KK101306 is expressed under the control of Scer\GAL4^Ilp6-NP1079, but not under the control of Scer\GAL4^NP3084, Scer\GAL4^GMR18E11, Scer\GAL4^nrv2.PS, Scer\GAL4^alrm.PD, Scer\GAL4^NP3233, Scer\GAL4^NP6520, Scer\GAL4^Mz709 or Scer\GAL80^repo.PL alone or under the combined control of Scer\GAL4^Ilp6-NP1079 and Scer\GAL80^repo.PL, Scer\GAL4^nSyb.PS and Scer\GAL4^Appl.G1a, or in clones under the combined control of Scer\GAL4^spin-NP2276 and Scer\GAL4^Act5C.PP (all of these expression conditions are in combination with Dicer-2.