Longitudinal studies of Aedes aegypti (Diptera : Culicidae) in Thailand and Puerto Rico: Blood feeding frequency

We used a histologic technique to study multiple blood feeding in a single gonotrophic cycle by engorged Aedes aegypti (L.) that were collected weekly for 2 yr from houses in a rural village in Thailand (n = 1,891) and a resi dential section of San Juan, Puerto Rico (n = 1,675). Overall, mosquitoes f rom Thailand contained significantly more multiple meals (n = 1,300, 42% do uble meals, 5% triple meals) than mosquitoes collected in Puerto Rico (n = 1,156, 32% double meals, 2% triple meals). The portion of specimens for whi ch frequency of feeding could not be determined was 31% at both sites. We e stimated that on average Ae. aegypti take 0.76 and 0.63 human blood meals p er day in Thailand and Puerto Rico, respectively. However, frequency of mul tiple feeding varied among houses and, in Puerto Rico, the neighborhoods fr om which mosquitoes were collected. In Thailand 65% of the mosquitoes fed t wice on the same day, whereas in Puerto Rico 57% took multiple meals separa ted by greater than or equal to 1 d. At both sites, the majority of engorge d specimens were collected inside houses (Thailand 86% Puerto Rico 95%). Th e number of blood meals detected was independent of where mosquitoes were c ollected (inside versus outside of the house) at both sites and the time of day collections were made in Puerto Rico. Feeding rates were slightly high er for mosquitoes collected in the afternoon in Thailand. Temperatures were significantly higher and mosquitoes significantly smaller in Thailand than in Puerto Rico. At both sites female size was negatively associated with t emperature. Rates of multiple feeding were associated positively with tempe rature and negatively with mosquito size in Thailand, but not in Puerto Ric o. Multiple feeding during a single gonotrophic cycle is a regular part of Ae. aegypti biology, can vary geographically and under different climate co nditions, and may be associated with variation in patterns of dengue virus transmission.