Evaluation of Midgut α-Amylase Activity in the Mediterranean Flour Moth, Anagasta kuehniella (Zeller, 1879) (Lep., Pyralidae(

In this study, larval midgut α-amylase activity of the Mediterranean flour moth reared on wheat flour under laboratory conditions was studied. Enzyme activity was evaluated by using a commercial kit and an autoanalayzer device. Specific enzyme activity was measured as international unit per mg protein (IU/mg Protein). In this study, some α-amylase enzyme properties such as optimum temperature and pH of enzyme activity, enzyme activity during different hours of the day and night, enzyme activity at different developmental stages of adult male and female, effect of starvation period, and the effect of storage conditions of enzyme at specified periods in two different temperatures were studied. The results revealed that incubation temperature significantly affected enzyme activity for both sexes and optimal enzyme activity was detected in 40˚C for both male and females. pH values also significantly affected enzyme activity and the optimal pHs for amylase activity in both sexes were 5. Effects of enzyme concentration on α-amylase activity were significant in both sexes. Increasing the concentration of enzyme in both sexes caused a sharp increase in enzyme activity. Storage period in -20˚C did not decreased enzyme activity significantly in both sexes, but storage period in 4˚C in males significantly decreased the activity in comparison with the control. The results of studying enzyme activity during 24 hr. periods showed significant differences during day and night and the most and the least enzyme activities in both sexes were recorded in 12 and 24 o’clock, respectively. Enzyme activity in different developmental stages showed significant differences and the most enzyme activities were detected in 5th female larvae, 5th male larvae, 4th male and females, female and male pre-pupa, and female and male adults, respectively. In male and female pupae, no detectable activity was observed.Enzyme activity in male and female fifth instar larvae showed Significant difference. Starvation periods significantly affected the digestive enzyme activity in both male and female larvae and the trends of enzyme activity during 4 days of starvation was the same in both sexes. The most and the least enzyme activity were detected 2 and 4 days after starvation, respectively.