RATE OF DIGESTION OF CR-51 HEMOGLOBIN BY STOMOXYS-CALCITRANS (DIPTERA, MUSCIDAE)

Bovine hemoglobin labeled with 51Cr was used to follow the digestion of the blood meal in Stomoxys calcitrans and to determine the rate of digestion of 51Cr-labeled hemoglobin and the excretion of free 51Cr. Digestion of the labeled hemoglobin by untreated flies fed only fresh, labeled, heparinized bovine blood began within the first hour postfeeding and was completed within 48 h; digestion did not begin in treated flies (flies fed soybean trypsin inhibitor with the blood) for ca 24 h. After 24 h, the rate of digestion in control and treated flies was the same. Excretion of free 51Cr began at about 4 h in control flies and at 24 h in treated flies. Labeling with chromium can be used to follow digestion in vivo and is also useful in determining the volume of blood meals.