The Dispersion of Flies by Flight1

Abstract

Up to very recent years it has been generally held by entomologists that flies are comparatively limited in the distances which they will go from breeding places. Dr. Parker's work in Montana indicated that the house-fly is normally migratory in habit and he succeeded in obtaining specimens nearly two miles from the point of liberation. In 1916. the authors conducted some preliminary experiments in which colored flies were liberated in the vicinity of packing houses and a considerable number of these were recovered quite promptly in traps placed in the yard of the packing establishments, a flight of about three-fifths of a mile. The flies liberated in this experiment consisted largely of blowflies of the species Chrysomyia rnacellaria and Phormia regina . Later in the same summer a series of experiments was carried out to determine the distance of flight of several species of blowflies and house-flies under rural conditions. The flies were liberated at a point near the intersection of two roads and four traps were placed at given distances in the four cardinal directions from the point of liberation. A total of 1,745 colored flies were recovered in the sixteen recovery traps and a considerable number of these were in the outer ring of traps which was approximately three miles from the point of release. Another experiment was conducted immediately following this in which the traps were moved outward in the four directions to points approximately 2, .3, 4 and 5 miles from the point of liberation. House-flies, screw-worm flies and the Anthomyid, Ophyra leucostoma , were recovered in some of the most distant traps.