Measuring Behavior 2005: Takken and Spitzen

Analyzing the flight behaviour of malaria mosquitoes: A challenge in 3 dimensions

W. Takken and J. Spitzen

Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands

Malaria is still one of the scourges of the third world, causing millions of infected persons and 1-3 million deaths each year. The disease is transmitted by Anopheline mosquitoes, which require blood for egg production. It has been proposed that interruption of mosquito-host contact would be the most effective method of malaria prevention as parasite transmission will then cease. Mosquitoes find their hosts by olfaction. The smell of the host can vary, and this determines the efficiency with which the mosquito can locate her host. We are interested to identify the chemical cues that constitute the attractive odours and how the mosquito navigates upwind while stimulated by these cues.

Single mosquitoes were exposed to single odours or blends of odours in a wind tunnel. Their upwind flight tracks were recorded with two solid state cameras, mounted under 15 degree angles above the wind tunnel. The flight images were taped synchronically by computer-controlled video recorders using two frame grabbers. After completion of a series of trials, the video recordings for each camera were played back. Within each image frame, the two-dimensional position of the mosquito was determined. By subsequently combining the information from the two different camera views, the three-dimensional position of the mosquito was reconstructed and stored. Special measurement and analysis software was developed to automate the analysis process, reconstruct the .ight path in three dimensions, as well as to extract behavioural parameters for characterization of the flight paths. Additionally, flight parameters for individual mosquitoes were compared for different zones in the wind tunnel viz. inside- or outside the odour plume. The presentation will show the results of a first series of 3D images and discuss the difference between odour alone and odour + heat as flight mediators of these important mosquitoes.

Paper presented at Measuring Behavior 2005 , 5^th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.