Physiological aspects of multiple blood feeding in the malaria vector Anopheles tessellatus

The malaria vector Anopheles tessellatus is able to take several blood meal s in a gonotrophic cycle. The fecundity is largely dependent on the first b lood meal and is not generally increased by subsequent blood meals during a gonotrophic cycle. Larval rearing densities influenced adult body size. Th ere is an inverse relationship between wing length and larval rearing densi ties. Smaller mosquitoes produced from larvae reared at higher densities ha d reduced body reserves of protein, lipid and carbohydrates. At emergence, ovarian development in An. tessellatus is in the previtellogenic stage and it remained at this stage until the intake of a blood meal. The number of o varian follicles is related to wing length and, irrespective of adult body size, An. tessellatus developed oocytes to maturity with a single blood mea l. This is attributed to the availability of metabolic reserves above the t hreshold level required for further development of oocytes. Mosquitoes that took more than one blood meal had largely digested their previous blood me al and had ongoing vitellogenesis. Blood meals subsequent to the first one apparently contribute mainly to increasing metabolic reserves. The stimulus for a second and third blood meal in An. tessellatus appears to be complet ion of the digestion of the previous blood meal. There was no evidence that multiple blood meals taken in the first gonotrophic cycle influenced fecun dity significantly in the second cycle. (C) 2000 Elsevier Science Ltd. All rights reserved.