Multiple blood meals within one gonotrophic cycle were taken readily at 6-24-hr intervals by nulliparous female Anopheles albimanus Wiedemann. Up to five blood meals were ingested and with each blood meal, more primary follicles matured as well as some secondary ones. This produced an irregular oviposition pattern that questioned the concept of gonotrophic concordance. The first blood meal initiated limited vitellogenesis and the maturation of few follicles. Instead, protein was diverted to the synthesis of maternal, extraovarian lipid and protein deposits; fecundity increased with successive blood meals. This pattern of protein and energy utilization may be explained in terms of the low caloric lipid and protein content of nulliparous females before the first blood meal. In An. albimanus, a critical female body size, =0.25 cal of lipid per female, was necessary for the initiation of oogenesis; below this threshold at least two blood meals were required for follicle maturation. Less than 10% of the caloric input from a blood meal was utilized in the synthesis of ovarian protein and lipids, whereas a similar percentage was transferred to maternal deposits of protein and lipid. In nonoogenic females, a replete blood meal increased total body protein and lipid by 17 and 113%, respectively. Altogether, the efficiency of blood protein utilization was rather low, as indicated by losses of excretory nitrogen that regularly exceeded 75% of the input. Anopheles gambiae Giles and An. stephensi Liston also fed multiply, but fecundity was less affected. Instead, maternal deposits were synthesized from the blood meal in substantial amounts. In general, gonotrophic discordance also was found routinely in these anopheline species. The ratio of yolk protein to lipids varied inter-and intra-specifically, as well as among consecutive blood meals, indicating a considerable plasticity in the caloric distribution of these two yolk components.

Two types of trypsin activity were detected in Anopheles alhimanus, a constitutive and an inductive component, which have identical imrnunopatterns. The constitutive trypsin in synthesized shortly after eclosion and i s retained in the rnidgut epithelial cells. The inductive trypsin is synthesized and released continuously after a blood meal has been ingested; maximal activities vary between 12 h and 18 h after a blood meal. Once digestion is completed, trypsin i s excreted, but the constitutive trypsin level is restored within 24 h, before the next blood meal is taken. In A. garnbiae, A. stephensi, and A. quadrimaculatus, the constitutive trypsin component is also present, but at much lower levels. In A. albimanus fed multiple blood meals at 24 h intervals, trypsin oscillates at nearly maximal levels as long as blood is present in the midgut and depending on the ovarian status. Expression of the two trypsin components in A. alhimanus was found to be independent of the neurosecretory system, but synthesis of the constitutive trypsin appears to require the presence of the corpora allata. In all species tested, chyrnotrypsin is secreted after a blood meal in a similar temporal pattern as trypsin, but it is never present before the blood meal. Reinvestigating several aedine species for the presence of chymotrypsin by using different substrates revealed measurable quantities in blood-fed females compared to earlier reports. Equally, aminopeptidase activity is present in all species tested and characterized by a constitutive component. Its activities follow different temporal patterns than the endopeptidases. o 1995 WiIey-Liss, Inc.

Chymotrypsin and trypsin inhibitors persist throughout all developmental instars of Aedes aegypti. After a blood meal, inhibitor activity against chymotrypsin was more than double that of sugar‐fed females, but only weak activity was detected in midguts where proteinase inhibitors has been thought to regulate proteinases during blood digestion. A fourfold increase in the ratio of abdominal/thoracic inhibitor activity after the blood meal strongly suggested that fat body, or other abdominal tissues, represent the major source of inhibitor. Chymotrypsin inhibitor activity was deposited in maturing oocytes. Similar results were obtained with blood‐fed Anopheles albimanus. Chymotrypsin inhibitor was active against different mosquito proteinases and against bovine α‐chymotrypsin and trypsin, but not against subtilisin, pancreatic elastase, or fungal proteases; chymotrypsin inhibitors did not interfere with bacterial growth. The hypothesis on the regulation of blood digestion through the action of proteinase inhibitors during the gonotrophic cycle was abandoned and its involvement in the phenoloxidase cascade in the mosquito egg chorion is suggested instead. Arch. Insect Biochem. Physiol. 36:315–333, 1997. © 1997 Wiley‐Liss, Inc.