Natural Plant Sugar Sources of Anopheles Mosquitoes Strongly Impact Malaria Transmission Potential

Abstract

An improved knowledge of mosquito life history could strengthen malaria vector control efforts that primarily focus on killing mosquitoes indoors using insecticide treated nets and indoor residual spraying. Natural sugar sources, usually floral nectars of plants, are a primary energy resource for adult mosquitoes but their role in regulating the dynamics of mosquito populations is unclear. To determine how the sugar availability impacts Anopheles sergentii populations, mark-release-recapture studies were conducted in two oases in Israel with either absence or presence of the local primary sugar source, flowering Acacia raddiana trees. Compared with population estimates from the sugar-rich oasis, An. sergentii in the sugar-poor oasis showed smaller population size (37,494 vs. 85,595), lower survival rates (0.72 vs. 0.93), and prolonged gonotrophic cycles (3.33 vs. 2.36 days). The estimated number of females older than the extrinsic incubation period of malaria (10 days) in the sugar rich site was 4 times greater than in the sugar poor site. Sugar feeding detected in mosquito guts in the sugar-rich site was significantly higher (73%) than in the sugar-poor site (48%). In contrast, plant tissue feeding (poor quality sugar source) in the sugar-rich habitat was much less (0.3%) than in the sugar-poor site (30%). More important, the estimated vectorial capacity, a standard measure of malaria transmission potential, was more than 250-fold higher in the sugar-rich oasis than that in the sugar-poor site. Our results convincingly show that the availability of sugar sources in the local environment is a major determinant regulating the dynamics of mosquito populations and their vector potential, suggesting that control interventions targeting sugar-feeding mosquitoes pose a promising tactic for combating transmission of malaria parasites and other pathogens.

Effects of Plant-Community Composition on the Vectorial Capacity and Fitness of the Malaria Mosquito Anopheles gambiae

“…12,13 The results are in stark contrast to those of two field studies conducted with An. sergentii, in which vectorial capacity was reported to be many times higher in a sugar-rich oasis than in a sugar-deficient oasis, 19,20 a result of higher biting rate and greater survival in the sugar-rich oasis. Whether this finding was caused by differences in the biology of the two species, or a reflection of the difference between the field and confined environments, is not known.…”

“…sergentii Theobald in two oases were reported to differ in vectorial capacity by a factor of 250, in favor of the oasis with two prominent sugarbearing plants. 19 In a second study at the same site and in an adjacent month, vectorial capacities differed by a factor of 7,20 nonetheless a large difference.…”

Volatile phytochemicals as mosquito semiochemicals

“…Furthermore, newly emerged females of small size have been shown to require an initial sugar or blood meal to develop their follicles to stage II before undergoing vitellogenesis and egg maturation (Lounibos and Conn, 1991; Briegel and Horler, 1993). Sugar also plays an important role in the early stages of adult development and, in nature, the availability and abundance of sugar sources determine the frequency of sugar feeding (Van Handel et al, 1994; Martinez-Ibarra et al, 1997; Gu et al, 2011). …”

Attractive Toxic Sugar Baits: Control of Mosquitoes With the Low-Risk Active Ingredient Dinotefuran and Potential Impacts on Nontarget Organisms in Morocco

“…This novel form of vector control targets the sugar feeding behavior of male and female mosquitoes in nature (Müller and Schlein 2006,2008; Schlein and Müller 2008; Müller et al 2008, 2010a,b,; Beier et al 2012). ATSB methods developed and field-tested in the Middle East, the United States, and Africa demonstrate how they literally decimated local populations of anopheline and culicine mosquito species (Müller and Schlein 2006, 2008; Müller et al 2008, 2010 a; Gu et al 2011; Beier et al 2012). Similar successful ATSB field trials also controlled Culex quinquefasciatus Say (Müller et al 2010a) and Aedes albopictus Skuse (Qualls et al 2012, Naranjo et al 2013) from storm drains, cisterns, wells, and residential backyards in Florida.…”