General presentation of the species, by Philippe Lambret and Jean Pierre Boudot:
" We call remind a number of characteristics in order to better understand the migratory behavior of this species. Its occurrence area extends from the South of Africa to the North of Europe and to India. It is native to the tropical and Mediterranean zones where the larvae quickly develops, preferentially in temporarily or permanent shallow waters. This compulsory migration forces
Assessment of the 2011 migration in France by Philippe Lambret and Clémence Deschamps:
"This migratory flux to occidental Europe and particularly to France is without known precedent. 177observers (of which I am part of) have collected 560 data in France, spread in 57 departments and corresponding to 18 regions. The majority of the data has been collected between April and June, the second wave was noted from July till November, with at times the observation of over a thousand individuals flying in from the South... In France, they scattered in diverse environments of stagnant water, ponds, vegetated gravel pits and lakes."