DOI: 10.5061/dryad.8w9ghx3vb
title: Spatial and temporal characteristics of laboratory-induced Anopheles coluzzii swarms: shape, structure and flight kinematics

description: Anopheles mosquitoes mate at sunset in aerial swarms formed by males near
 a visual ground marker, and where females come into to find a mate.
 However, the process of how swarms are formed and maintained remains
 poorly understood. In the context of effective malaria vector control, the
 development of mating-based control methods such as sterile, incompatible,
 or genetically modified insect techniques, require a good knowledge of the
 flight behaviour of Anopheles gambiae s.l. in mating swarms. Here, we used
 a stereoscopic videography-based tracking system, to study the flight
 behaviour of swarming Anopheles coluzzii males under laboratory
 conditions. Using this approach, we characterized the three-dimensional
 spatial and temporal flight kinematics of male mosquitoes swarming above a
 visual ground marker. We observed that the location, shape, and volume of
 swarms were highly stereotypic, consistent over the duration of the
 swarming activity, regardless the number of individuals in the swarm. In
 contrast, the distance to the nearest neighbour in the swarm did vary with
 decreased with swarm size, as it reduced on average 7 mm per mosquito
 recruited into the swarm, and was thus minimal at peak swarming (~10 cm).
 Regardless of swarm size, the stereotypic mosquito swarm has an elliptical
 cone shape, with the major and minor ellipse axes perpendicular and
 parallel to the sunset horizon, respectively. More precisely, we found
 that swarm width and flight speeds in the swarm were 1.7 and 1.6 times
 higher perpendicular to the sunset horizon than parallel to it,
 respectively. Using a sensory system-informed model, we show that swarm
 location and shape can accurately be modelled on visual perception of the
 ground marker. To control swarm height, swarming individuals maintain an
 optical angle of the marker ranging from 24° to 55°. Limiting the
 deviation of the viewing angle to 4.5% of the maximum value at a given
 height, results in the elliptical cone swarm shape. Based on these
 experimental and modelling results, we discuss the implications of these
 finding in mating success, speciation and for vector control.
description: # Spatial and temporal characteristics of laboratory-induced Anopheles
 coluzzii swarms: shape, structure and flight kinematics
 [https://doi.org/10.5061/dryad.8w9ghx3vb](https://doi.org/10.5061/dryad.8w9ghx3vb) ## Description of the data and file structure **Data S1**: Database of the experiment. Flight tracks of Anopheles coluzzii mosquitoes swarming above a swarm marker in sunset simulated laboratory conditions. A Matlab (all_data.mat) file containing three-dimensional tracks of all flying mosquitoes, described as the time t (s) and the spatial {x, y, z} (m) coordinates of the mosquito at each video frame. The coordinates are in meters, and in the world reference frame as defined in figure 1, with z oriented vertically up, and the origin of the coordinate frame at the center of the swarm marker. The trajectories were determined as described in the materials and methods. **Data S2**: Two databases used for the statistical analysis in R. 1\. The database "flight_activity" contains the data on the flying activity of mosquitoes recorded during the three swarming phases (phase) and the six experimental replicates (replicate). These data are: \- the maximal number of flying mosquitoes (n_flying), \- the maximal number of flying mosquitoes that swarmed (n_swarming), and \- the number of mosquitoes used for each replicate (n_released). The number of flying mosquitoes, number of swarming mosquitoes and the swarming proportion, were analyzed as a function of the three swarming phases (start, peak and ending phase). 2\. The database "flight_kinematics" contains flight kinematics parameters of each swarming mosquitoes/trajectory (obj_id) recorded during the three swarming phases (phase) and the six experimental replicates (replicate). The flight kinematics parameters are: \- the mean location along the three axes (x,y and z_location), \- the mean standard deviation of the location along the three axes (x,y and z_location_std), \- the mean velocity along the three axes (x,y and z_velocity), \- the mean 3D velocity (velocity). \- the mean acceleration along the three axes (x,y and z_acceleration), \- the mean 3D acceleration (acceleration), \- the mean distance to the nearest neighbor (min_distance), and \- the mean swarm size (nb_animal) These flight kinematics parameters was analyzed, first as a function of the three-dimension axes (x, y and z-axis), and then as a function of the three swarming phases (start, peak and ending phase), and finally as a function of the swarm size (number of mosquitoes in the swarm at the peak phase). ## Code/Software (Zenodo) **Code S1**: Analysis codes. Contains all original Matlab codes that were written to perform the analysis of the article and to generate the figures. To run the full analysis in Matlab: \- Move the dataset in \_Data \- Run main.m, figures will be saved in the \_Figures folder. **Code S2**: The statistical analyses of the data were performed using R (version 4.3.1). The R script named "statistical analyses" contains all the codes used for the statistical analyses and the graphics.