Impact of four diets on pupal and larval total protein and digestive α-amylase activity in Ephestia kuehniella (Lepidoptera: Pyralidae)

Mediterranean flour moth, Ephestia kuehniella Zeller, is important for mass rearing of parasitoid insects such as Bracon wasps and it's feeding on cereals leads to economic losses in flour mills. In current research, the effects of four different diets: wheat, barley, oat, and maize flours, on protein content of larval and pupal whole-body, gut and fat bodies of the last instars and the digestive α-amylase activity were evaluated. In addition, their protein patterns were compared using polyacrylamide gel electrophoresis (SDS-PAGE). The protein contents of fifth instars whole-body, fat bodies, gut, and also pupa varied in different diets. On the whole, the lowest protein levels were found in all experiments in oat and the highest in barley and wheat. Other biological parameters such as insect weight and digestive α-amylase activity were also significantly affected by the decrease in protein content. The results obtained from the estimation of protein content by a colorimetric method and SDS-PAGE were consistent with each other; the low or high protein contents were also clearly visible in the gels. According to the results of enzyme activity and protein contents of insects reared on different diets, barley and wheat are reported to be appropriate diets for this pest, while oat and maize are not suitable diets.