Anopheles arabiensis larval inspection sites in La Reunion from 1996 to 2009. The figure shows the typical area which was mapped and serves to illustrate the land division into sampling grid cells during routine larval surveys. Box A shows the location of study sites in La Reunion. Red line indicates the altitudinal limit of each sampling zone, blue lines shows study region borders in western, southern and north-eastern region. Box B indicates an example of sampling grids from 1996 to 2009 in the north-eastern study area (as in western and southern zone).