Fecundity of the Stable Fly: Effect of Soybean Trypsin Inhibitor and Phospholipase A Inhibitor on the Fecundity

Abstract

Fecundity of female stable flies, Stomoxys calcitrans (L.), was reduced and oviposition was delayed when plasma, serum, or erythrocytes were fed instead of whole bovine blood or defibrinated bovine blood. When 3 mg SBTI/ml soybean trypsin inhibitor (SBTI) was added to plasma, serum, or erythrocyte diets, fecundity was reduced to zero, and when SBTI was added to whole blood or defibrinated blood, fecundity was reduced 71 and 79%, respectively. Females that fed on whole blood containing 3 mg/ml phospholipase A inhibitor, ((2-hydroxyethylammonium acetate) [2,3-bis(octadecanoyl distearoyloxy)propyl]), deposited eggs 24 h earlier and on the average deposited more eggs than females that fed solely on whole blood. The proteolytic activity of midgut homogenates prepared from males that fed on blood meal diets with and without inhibitors indicates that de novo synthesis of digestive enzymes did occur.