Changes in the circadian flight activity of the mosquito Anopheles gambiae in relation to insemination, feeding and oviposition

ABSTRACT. The effects of different physiological inputs on the circadian pattern of flight activity were examined in Anopheles gambiae. Males and virgin females had a similar activity pattern in which the initial (light-off) peak accounted for a large proportion of the total activity. Starvation caused an increase in activity, but the basic pattern remained unchanged. After insemination, the initial peak in females was greatly reduced, while activity later in the dark phase increased. Blood-feeding was followed by a depression of activity for 2–3 days, but there was an increase in the relative importance of the initial peak until oviposition had taken place. These changes are consistent with the switches in behaviour in the wild, from mating to host-seeking, and then between host-seeking and oviposition. Our results suggest that the changes are brought about by factors which have differential effects on the components of the circadian pacemaker.