Biology of Male Tabanids (Diptera) Aggregated on a Mountain Summit in Southwestern Quebec

Males of 17 species of Chrysops, Hybomitra , and Tabanus were collected on the summit of Mount Rigaud in southwestern Quebec, Canada. Male flight activity extended from late May to late August; greatest species diversity occurred in mid-June. Males were more abundant than females of the same species and usually had a longer seasonal distribution. Males exhibited 2 types of behavior associated with mating: hovering and waiting. Prevalence of nectar feeding as determined by cold anthrone test was 73% among males, including 43% in waiting males and 84% in hovering males. The most common pollen grains observed on Hybomitra sodalis males came from nectariferous plants with large inflorescences. Sunlight stimulated male activity when temperature was suitable for flight.