Frequent blood-feeding and restrictive sugar-feeding behavior enhance the malaria vector potential of Anopheles gambiae s.l. and An. funestus (Diptera: Culicidae) in western Kenya

• Published in: Journal of medical entomology 1996-07, Vol.33 (4), p.613-618
• Main Author: Beier, J.C. (Tulane University, New Orleans, LA.)
• Format: Article
• Language: English
• Subjects: ALIMENTACION RACIONADA; ALIMENTATION RATIONNEE; Animals; ANOPHELES; Anopheles - parasitology; Anopheles - physiology; Anopheles funestus; ANOPHELES GAMBIAE; AZUCAR; Biological and medical sciences; COMPORTEMENT ALIMENTAIRE; Culicidae; Diptera; Feeding Behavior; Female; FRECUENCIA DE LAS COMIDAS; FREQUENCE DES REPAS; Fructose - pharmacology; Fundamental and applied biological sciences. Psychology; HABITOS ALIMENTARIOS; Host-Parasite Interactions; Insect Vectors - parasitology; Insect Vectors - physiology; KENIA; KENYA; MALARIA; Malaria, Falciparum - parasitology; Malaria, Falciparum - transmission; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; OVIPOSICION; Plasmodium falciparum - isolation & purification; PONTE; SUCRE; TRANSMISION DE ENFERMEDADES; TRANSMISSION DES MALADIES; VECTEUR DE MALADIE; VECTORES; Vectors. Intermediate hosts
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1093/jmedent/33.4.613

Natural blood-feeding and sugar-feeding behaviors were investigated for populations of Anopheles gambiae s.l. and An. funestus Giles at 2 sites in western Kenya. During peak levels of malaria parasite transmission, 85% of 1,569 indoor-resting females contained fresh blood meals. Findings that up to 55.4% of blood-fed resting females and 72.0% of host-seeking females had either stage IV or V oocytes provided strong evidence that females were refeeding before oviposition. Such gonotrophic discordance was common throughout the year for both An. gambiae s.l. and An. funestus. Determinations of gonotrophic cycles for freshly blood-fed mosquitoes collected inside houses indicated that only 60.0% of 1,287 An. gambiae s.l. and 60.0% of 974 An. funestus oviposited eggs after a single blood meal. The timing of oviposition was irregular as indicated by relatively high coefficients of variation for An. gambiae s.l. (44.0%) and An. funestus (35.9%). Associated with frequent blood feeding was a surprisingly low rate of sugar feeding; only 6.3% of 1,183 indoor-resting and only 14.4% of 236 host-seeking anophelines were positive for fructose. Natural patterns of frequent blood feeding, year-round gonotrophic discordance, irregular oviposition cycles, and limited sugar feeding illustrate that anopheline mosquitoes have complex behavioral and physiologic means for adapting to their environment. In western Kenya, for example, adaptations for frequent blood feeding by An. gambiae s.l. and An. funestus potentiates their ability to transmit malaria parasites, well beyond that predicted by standard measures of vectorial capacity