Desiccation tolerance as a function of age, sex, humidity and temperature in adults of the African malaria vectors Anopheles arabiensis Patton and Anopheles funestus Giles

Abstract

Abstract Adult mosquito survival is strongly temperature and moisture dependent. Few studies have investigated the interacting effects of these variables on adult survival and how this differs among the sexes and with age, despite the importance of such information for population dynamic models. For these reasons, the desiccation tolerance of Anopheles arabiensis Patton and Anopheles funestus Giles males and females of three different ages was assessed under three combinations of temperature and humidity. Females were more desiccation tolerant than males, surviving for longer periods than males under all experimental conditions. In addition, younger adults were more tolerant of desiccation than older groups. Both species showed reduced water loss rates (WLR) as the primary mechanism by which they tolerate desiccation. Although An. arabiensis is often considered to be the more arid-adapted of the two species, it showed lower survival times and higher water loss rates than An. funestus. The current information could improve population dynamic models of these vectors, given that adult survival information for such models is relatively sparse.