Light-on and Light-off Effects on the Circadian Flight Activity in the Mosquito Anopheles gambiae

Abstract

A PRELIMINARY investigation of the flight activity of female Anopheles (Cellia) gambiae Giles (Lagos strain) fed on sugar has been undertaken using a modification of the recording technique described by Jones¹. Groups of five or ten recently emerged adults were placed in a ‘Perspex’ walled chamber (c. 1.5 l.). This was placed in a soundproof box in a constant temperature room, maintained at 24°–26° C. The mosquitoes were supplied with a small quantity of 15 per cent glucose solution with a cotton wool “wick”, which also served to maintain a relative humidity in the chamber of 65–85 per cent. Artificial lighting (150–200 lux) was used during both the rearing and experimental periods, and the light régimes were controlled with a simple time switch. Flight activity was recorded acoustically for periods of up to 1 week, and a direct record of the activity was made with a pen marker on a kymograph with a continuous paper roll attachment. A similar recording “channel”, without mosquitoes, was used to record any unwanted acoustic or electronic interference which was loud enough to operate the pen markers.