[The small halophilic zygopteric odonate, Mortonagrion hirosei, of central Japan, a predator utilizable against tiny stinging diptera of coastal salt marshes, especially Ceratopogonidae of the genera Culicoides and Oecacta, pests of sea shores in southwestern U.S.A. and Caribbean area].
Among stinging diptera pullulating in coastal salt marshes Ceratopogonidae gnats (mainly of genus Culicoides and Oecacta) are especially troublesome, particularly in Southeastern U. S. A. and Caribbean area, escaping attacks of most predators by their tiny size. But the zygopteric odonate insect Mortonagrion hirosei is well fitted for hunting those minute diptera, by its tiny size and its behaviour, seeking shelter between halophilic plants (2 facts explaining that it was not discovered in central Japan before 1971...). Its larvae, living in brackish waters of coastal lagoons, can devour those of Ceratopogonidae and at least young stages of those of Mosquitoes whose some halophilic species are dangerous vectors of diseases. According to similarity of climates M. hirosei can certainly thrive in Southeastern U. S. A., and probably in Southern Europe. At lower latitudes problems for completion of annual cycle could perhaps arise from lack of hivernal cooling. It is necessary to make at the world scale methodical researches for other species of zygopteric odonates of similar ecology which could exist in other countries, both for avoiding harmful competition of introduced M. hirosei with native species still unknown and for fulfilling the same ecological function in areas of climate no suitable for this Japanese insect. Introduction of M. hirosei in new geographic areas would be very useful, too, for protection of this interesting species threatened by human activities in its natural biotopes, made of discontinuous and rather little areas.
D000818:Animals; D002519:Ceratopogonidae; D007313:Insecta; D007564:Japan; D010572:Pest Control, Biological; D014481:United States; D014900:West Indies
Le petit odonate zygoptère halophile Mortonagrion hirosei du Japon central. Un prédateur utilisable contre les petits diptères piqueurs des marécages saumâtres littoraux, notamment les Cératopogonidés des genres Culicoides et Oecacta, fléau des rivages du sud-est des U. S. A. et des Caraïbes.