DIURNAL BEHAVIOR AND BITING HABITS OF BLACK FLIES (DIPTERA: SIMULIIDAE) IN THE FORESTS OF QUEBEC

Abstract

Studies in the region of Baie Comeau, Quebec, from 1954 to 1956, showed that black flies were most active in the morning 1 to 2 hours after dawn and in the evening [Formula: see text] to 1 hour before sunset. Flight activity appeared to depend on light intensity if the temperature was not below 45° F, the wind velocity not above 2 m.p.h., and the relative humidity not below 50%. In the morning, activity was greatest at higher levels of light intensity, i.e., 20 ft-c, than in the evening, 5 ft-c. Activity increased before thunderstorms and rain and the increase appeared related more to the change in light intensity than to changes in atmospheric pressure or humidity. At night, black flies moved to resting places in the tops of the trees, probably because of the more suitable light intensity at the higher levels just before dark. Oviposition commenced in the late afternoon and continued until dark except on overcast days, when it commenced in early afternoon. Simulium (Simulium) venustum Say bit man mainly on the back of the neck.