Sugar is the only source of energy for adult male mosquitoes, but the extent to which the lack of opportunities to sugar feed impacts a cohort of males’ ability to inseminate female mosquitoes is unknown. We report here on an investigation on the impact of sugar availability on the mating performance of male Anopheles gambiae in both mesocosms and in cages.

Over a ten day period, each day twenty male and female mosquitoes were allowed to emerge into mesocosms; enclosures with simulated natural conditions, and cages. Sugar was either absent or present in the form of 10% sucrose solutions. Every night female mosquitoes were given the chance to blood feed. After 10 days all surviving mosquitoes were inspected for insemination.

In the mesocosms 10.9% of the females were inseminated when sugar was not available, against 49.7% when sugar was present. Enclosure size also influenced insemination rates; in the cages 23.5% of the females were inseminated in the absence of sugar, whereas 76% were inseminated in the presence of sugar. No significant differences in biting activity were discovered. Survival of females after ten days was 51.6% with sugar, and 25.6% with water only in the mesocosms. In the cages female survival was 95% with sugar and 73% without.

We conclude that insemination capability of males in the absence of sugar sources is greatly diminished but not completely absent under semi-field conditions, and stress the importance of using an appropriately scaled experimental system for behavioral studies of this medically important species.