Fig. 1: Flight altitude, seasonality, wind speed and abundance of migratory anopheline species.

a, The relationship of altitude (height of the collecting panel) to panel density (blue) and aerial density (orange, mosquitoes per 10⁶ m³ of air), for the five most-common anopheline species (Table 1). Bubble size is proportional to mosquito density (the value shown in the bubble × 10³); when the value is zero, only a dot is shown. The number of sampling nights for each of the collecting-panel heights is shown on the left. b, Monthly panel density (n = 1,894 panels) for the five most-common species (Table 1), overlaid by the length of migration period (dashed lines). Values for A. squamosus were divided by three to preserve the scale. The sampling month for species that were collected only once or twice is shown by letters: c1, A. namibensis; g, A. gambiae; m1, Anopheles Mali species 1; m2, Anopheles Mali species 2; nC, A. sp. nr concolor. c, Distribution of the mean nightly wind speed at flight height on nights on which one or more anopheline mosquitoes were collected. Wind-speed data were taken from ERA5 database after matching the height of the collecting panel to the nearest vertical layer (Methods). The corresponding box and whisker plot (top) shows the median, mean, quartiles and extreme values overlaid by arrows indicating the mean and 10th and 90th percentiles (red). d, The number of mosquitoes per species that cross, at altitude (50–250 m above ground level), imaginary lines perpendicular to the prevailing wind direction. Migrants per night per 1 km (right y axis) are superimposed on the annual number of migrants per 100-km line (left y axis).