Sugar Deprivation Reduces Insemination of Anopheles gambiae (Diptera: Culicidae), Despite Daily Recruitment of Adults, and Predicts Decline in Model Populations

• Published in: Journal of medical entomology Vol. 46; no. 6; pp. 1327 - 1337
• Main Authors: Stone, C.M, Taylor, R.M, Roitberg, B.D, Foster, W.A
• Format: Journal Article
• Language: English
• Published: England 01.11.2009
• Subjects: adult insects; Animals; Anopheles - metabolism; Anopheles - physiology; Anopheles gambiae; fecundity; Feeding Behavior; Female; Humans; insemination; Insemination - physiology; Male; mating frequency; mosquito control; polyandry; population characteristics; Population Density; prediction; recruitment; Sexual Behavior, Animal; sucrose; Sucrose - metabolism; sugar feeding
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1603/033.046.0611

Our research tests the hypothesis that the inability to sugar-feed reduces the insemination rate in mosquito populations. To test this, we measured the effects of sugar availability on cumulative insemination performance of male Anopheles gambiae Giles s. s. (Diptera: Culicidae) during 10-d periods of continual emergence of equal numbers of both sexes, and we evaluated the implications at the population level with a matrix population model. On each day of each of four replicates, 20 newly emerged mosquitoes of each sex were recruited into the populations within two mesocosms, large walk-in enclosures with simulated natural conditions. Each mesocosm contained a cage to replicate the experiment on a small scale. Scented sucrose was absent or present (control). A human host was available nightly as a bloodmeal source in both mesocosms. Sugar availability and enclosure size significantly influenced female insemination. In the mesocosms, with sugar 49.7% of the females were inseminated, compared with 10.9% of the females without sugar. In the small cages, the insemination rates were 76.0 and 23.5%, respectively. In the mesocosms, cumulative survival of females after 10 d was 51.6% with sugar and 25.6% without sugar. In the cages, female survival was 95 and 73%, respectively. Sensitivity analysis of the population projection matrix shows that both reduced male survival and reduced mating capability due to a lack of sugar contributed to lower insemination rates in females, and in the absence of sugar the insemination rate was lowered to an extent that led to population decline.