SEASONAL DISTRIBUTION AND PARITY OF HOST-SEEKING HORSE FLIES (DIPTERA: TABANIDAE) FROM A PASTURE NEAR SEVEN SISTERS, MANITOBA

Abstract

AbstractTwenty species of Tabanidae in three genera [Hybomitra (15 spp.), Tabanus (four spp.), Haematopota (one sp.)] were caught in Manitoba horse fly traps from mid-May to mid-July in 1987, and from mid-May to mid-August in 1988. Hybomitra lurida (Fallen) and H. nitidifrons nuda (McDunnough) peaked in abundance in late May to early June; H. illota (Osten Sacken) and H. lasiophthalma (Macquart) in early June; H. affinis (Kirby), H. arpadi (Szilady), and H. zonalis (Kirby) in mid-June; H. epistates (Osten Sacken) and H. pechumani Teskey and Thomas in late June to early July. Abundance of H. trepida (McDunnough) peaked twice, in late June and early August. Tabanid density and diversity were greatest during June; few flies were present at the site after mid-July. For most species, at the beginning of the flight season, 80–100% of flies dissected were nulliparous. After approximately 1 month of flight activity, parity in all but three species reached levels approaching 100%, and remained high thereafter. Hybomitra lurida and H. nitidifrons nuda were 100% parous within 2 weeks of their first appearance in traps. Parity of H. trepida increased to 100% after 4 weeks, declined to 40% 2 weeks later, and returned to 100% after another 2 weeks.