Abstract
Seasonal prevalence and daily activities of tabanid flies were surveyed fortnightly during the period of July 7th to September 15th in 2011 at the Motoyama pasture in Esashi, Hokkaido and during the period of July 27th to September 5th in 2012 at the Minamisawa pasture in Horonobe, Hokkaido. The CO2 lured NZI traps were used to capture the flies in these pastures. A total of 9,478 individuals of flies including 5 genera and 12 species were captured at Esashi and 1,294 individuals including 5 genera and 8 species were captured at Horonobe. In Esashi, Tabanus nipponicus was captured as the most predominant species, and was followed by T. rufidens and in Horonobe, T. nipponicus and Haematopota tristis were predominant species. The seasonal prevalence curve of captured number of T. nipponicus showed a peak at mid-July and that of T. rufidens showed a peak at mid-August in Esashi, and that of Hae. tristis showed a peak at early-August and that of T. nipponicus showed a peak of mid-August in Horonobe. From the results obtained in this survey, the measures against these flies should be taken from July to late-August at both pastures.
