Abstract
Oryzaephilus surinamensis (L.), reared on three holidic diets at 32 ± 2 °C and 75 ± 5% relative humidity, required a dietary source of phenylalanine, irreplaceable by dietary tyrosine. This insect also required a dietary source of tyrosine for normal rate of development. On diets containing 1.0 mg of phenylalanine per gram, it used supplementary glycine more effectively than supplementary tyrosine as a replacement for phenylalanine omitted from the diet. On diets containing 1.0 mg of tyrosine per gram, it used supplementary phenylalanine more effectively than glycine. Emergent adults weighed less with 1.0 mg of dietary phenylalanine per gram than with higher concentrations. Adult weight was unaffected by decreasing concentrations of dietary tyrosine.