ARS | Publication request: Reconstructing the flight kinematics of swarming and mating behavior in wild mosquitoes

Submitted to: Journal of the Royal Society Interface
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 26, 2012
Publication Date: October 7, 2012
Citation: Butail, S., Manoukis, N., Diallo, M., Ribeiro, J.M., Lehmann, T., Paley, D.A. 2012. Reconstructing the flight kinematics of swarming and mating behavior in wild mosquitoes. Journal of the Royal Society Interface. 9(75)2624-2638.

Interpretive Summary: This manuscript reports a novel method for locating and following individual mosquitoes in three dimensional space over time in wild mating swarms from image data acquired from two cameras simultaneously (stereo). Using this method we have been able to quantify the velocity and direction of the flight of the malaria vector Anopheles gambiae in its habitat in West Africa. We found a fast rate of movement (1-3 m/s) and details on how individual males and females in the swarm orient themselves and move through space.

Technical Abstract: We describe a tracking system for reconstructing three-dimensional tracks of individual mosquitoes in wild swarms and present the results of validating the system by filming swarms and mating events of the malaria mosquito Anopheles gambiae in Mali. The tracking system is designed to address noisy, low-frame-rate (25 frames per second) video streams from a stereo camera system. Mosquitoes move fast (1–3 m/s) and appear as faded streaks in the images. We provide an adaptive algorithm to search for missing measurements and a likelihood function that utilizes streak endpoints to extract velocity information. A modified multi-hypothesis tracker probabilistically addresses occlusions and a particle filter estimates the trajectories. The output of the tracking algorithm is a set of track segments with an average length of 0.6–1 seconds. The segments are verified and combined under human supervision to create individual tracks up to the duration of the video (60–90s). We evaluate tracking performance using an established metric for multi-target tracking and validate the accuracy using independent stereo measurements of a single swarm. Three-dimensional reconstructions of An. gambiae swarming and mating events are presented.