The genetic transformation of a strain of PBW (APHIS strain) did not cause major changes in time sequenced life history parameters of the transgenic strain (EGFP strain of PBW) when compared to its non-transformed ancestors, the APHIS strain of PBW. However, there was a loss of fitness evidenced in the female’s ability to produce eggs. Egg survivability was also reduced in the EGFP strain. This loss of fitness under simulated mass rearing conditions is most likely due to the debilitating effects of extensive handling of the larvae and the disruption of the larval feeding cycle rather than effects associated with the transgeneic change. The maintenance protocol for selection of a homozygous strain of the EFGP colony required larval extraction from the diet in the 3 ^rd and /or 4 ^th instar, examination of the larvae under a microscope for gene expression then larval return to the diet. This involved considerable handling and was a major interruption of the normal larval feeding cycle.