In this study, the effects of relaxed mass-rearing conditions on Anastrepha obliqua (Macquart) production and quality were determined. Relaxed rearing conditions were defined by a reduction in the density of adult flies, from 80,000 to 60,000 flies per mass-rearing cage, and a reduction in the density of larvae, from 6.18 to 3.70 eggs/g of diet. In the parental generation, flies reared under relaxed conditions exhibited significant and a few non-significant changes – increased daily fecundity from 37 to 42 eggs per female, larval recovery from 80 to 91%, larval weight from 18.5 to 19.5 mg, pupation at 24 h from 92 to 96%, pupal weight from 13.5 to 14.3 mg, adult emergence from 92 to 94% and percentage of fliers from 89 to 90%. During the following 12 generations, non-significant differences were observed, but comparisons between relaxed and non-relaxed colonies were significant. The sexual competitiveness of males produced under relaxed conditions was similar to that of wild males.
