Concentration of Host Blood Protein During Feeding by Anopheline Mosquitoes (Diptera: Culicidae)1

During blood feeding, Anopheles stephensi ingested 2 to 10 µl of blood. It took such large meals by releasing large amounts of a red rectal fluid as it fed. Although the fluid contained intact erythrocytes, the female was able to concentrate the dietary protein in the midgut by a factor of about 2. Two larger species, An. albimanus and An. quadrimaculatus, consuming larger meals, released a clear rectal fluid and also concentrated their blood meals without losing protein. Therefore, gravimetric determinations of blood consumption would be misleading in Anopheles. Concentration of blood proteins during the act of feeding, before diuresis, is unique for Anopheles and led to increased fecundity when compared to blood meals given by enema. Similar to results with Aedes, fecundity was significantly lower with human than with guinea pig blood. It was further demonstrated that female Anopheles actually refed on successive days when a host was offered. In contrast to Aedes, subsequent blood meals produced an increase in the number of maturing oocytes.