Fecundity, Metabolism, and Body Size in Anopheles (Diptera: Culicidae), Vectors of Malaria

Abstract

In four Anopheles species, An. albimanus, An. gambiae, An. stephensi, and An. quadrimaculatus Say, total protein, lipid, and carbohydrate present at eclosion, after feeding on sucrose, and after extreme starvation were quantified to study the effect of teneral and maximal reserves on subsequent fecundity and to judge the extent of reserve mobilization and the minimal irreducible amounts required for survival. All parameters were regressed on body size, presented as the cubic value of wing length. Teneral reserves were isometric with body size, were considerably lower than previously reported for Aedes aegypti (L.) and were sexually dimorphic with respect to reserves and body size, all being slightly reduced in males. On the average, up to 70% of the teneral female lipids and up to 50% of their teneral protein could be mobilized during nutritive stress. Conversely, access to sucrose for a few days led to a pronounced glycogenesis (up to 509%) and lipogenesis (up to 450% of the teneral values), depending on the species. In absolute terms, lipogenesis prevailed over glycogenesis. On a caloric basis, up to 30% of the blood meal protein was utilized for synthesis of yolk protein and lipid, and another 15% was deposited as an extra-ovarian, maternal protein and lipid store, perhaps compensating for the limited teneral reserves. A complete nitrogen budget revealed that in a given class of body size, roughly 80% of the blood meal protein was catabolized and excreted through the three major pathways of uricotely, ureotely, and ammonotely. Quantification of the hematin in fecal samples allowed a stoichiometrical determination of the amount of blood ingested. Eco-physiological aspects of larval feeding, teneral reserves, blood meal utilization, and possible behavioral adaptations to these physiological constraints are discussed and compared with previous data on culicine mosquitoes, stressing the invalidity of generalizations among these taxa.