Effects of nectar and sugar on the longevity of the mosquito Anopheles gambiae s.l.

Mosquitoes regularly feed on plant nectar, which provides energy for key life-history traits, including longevity. However, the effects of nectar quantity and sugar composition on mosquito longevity remain poorly understood. To address this, we conducted two experiments. First, adult Anopheles gambiae s.l. fed on flowers of Thevetia nerifolia , Malvastrum coromandelianum , Ixora coccinea , and Tabernanthe iboga , or fruit of Carica papaya . We measured sucrose, fructose, and glucose concentrations in nectar and fruit juice, as well as mosquito longevity and sugar meal size. Second, mosquitoes received glucose, sucrose, fructose, or trehalose solutions at two energy concentrations (1.97 or 19.97 kcal per 100 ml), and longevity was monitored. In the first experiment, longevity ranged from 8.2 days on C. papaya to 21.1 days on M. coromandelianum . Interestingly, mosquitoes took larger nectar meals from plant species associated with greater longevity, whereas total sugar concentration had little effect on longevity. In the second experiment, sucrose increased longevity, whereas trehalose reduced it, with mean longevities of 14.1 and 4.8 days, respectively. These findings highlight the potential role of nectar plants in mosquito longevity and suggest that nectar composition, beyond sugar content, may contribute to mosquito survival.