EcR¹¹²/EcR^M554fs third instar larvae have the same number of Burs-immunoreactive CCAP neurons as wild-type controls. At 24-48 hours after puparium formation there are more Burs-immunoreactive abdominal CCAP neurons than in +/EcR^M554fs controls and some CCAP neurons retain larval features such as small soma size and larva-like projections.

An EcR-A mutant (EcR¹¹²/EcR^M554fs) does not protect normal Crz-expressing ventral-nerve cord neurons from programmed cell death.

EcR¹¹²/EcR^M554fs mutants show a range of lethal phases and a loss of coordination of larval wandering and pupariation behaviour. All EcR¹¹²/EcR^M554fs larvae survive to the third larval instar stage but show abnormal larval wandering behaviour. Unlike wild-type larvae, EcR¹¹²/EcR^M554fs third instar larvae continue feeding and often fail to wander in search of a suitable pupariation site, resulting in their pupariation on food. The mutants seem to physically resist pupariation and their aberrant movement causes the formation of a misshapen puparium. The predominant lethal period for EcR¹¹²/EcR^M554fs mutants is pupal stage P5 and a subset survive to later pupal stages. EcR¹¹²/EcR^M554fs pupae retain swollen salivary glands at more than 48 hours post pupariation, while wild-type salivary glands undergo autophagy at 14 hours post pupariation. Other internal structures, such as gastric cecae and larval midgut cells are not affected in the mutant pupae. Only ~2% of EcR¹¹²/EcR^M554fs mutants survive to the pharate adult stage and such mutants rarely eclose. These pharate adults have a range of defects, including abnormal operculum formation, heads that are compacted into the anterior portion of the puparium, larval mouth hooks that have not been ejected during pupal development and legs that have shortened, rounded tarsal segments with kinked femurs.

82% of EcR¹¹²/EcR^M554fs mutants survive to the second larval instar stage, 73% survive to the third instar and pupal stage, but all are dead by the adult stage.