In larva, expressed in all somatic and visceral muscles; level of expression lower relative to constructs carrying larger intron fragments. In adults, expressed in all somatic and visceral muscles of the head and abdomen; in adult thorax, expressed in somatic tubular muscles and in direct flight muscles, but not in the IMF (indirect flight muscles) or the TDT (tergal derepressor of the trochanters). In adults, also, the level of expression is lower relative to constructs carrying larger intron fragments.