Abstract: Variations in protein and carbohydrate levels correlated with the age and sex of Galleria mellonella (Linnaeus, 1758) (Lepidoptera: Pyralidae) in constant lightness and darkness were investigated. Tests were conducted under laboratory conditions at 28 ±2 °C temperature and 65 ± 5% relative humidity. Insects were fed on combs without honey. Protein level in 100 mg of adults increased in the first days of adult life of females in connection with their age and then decreased. No difference was observed in males. Carbohydrate level in 100 mg of adults increased in both sexes in connection with their age. In all tests carbohydrate and protein levels of females were found higher than males. Protein and carbohydrate levels of adult G. mellonella varied in connection with the photoperiod regimes implemented. Decrease in the nutrient levels was observed in constant darkness.