Tabanidae (Diptera) from the Amazon: XI. Seasonal activity of species from the eastern Amazon and correlation with climatic factors

The Tabanidae (Horseflies and deerflies) attracted to a horse, were studied in the eastern Amazon Basin. Year-long studies of the seasonal activity patterns of tabanid species were made in two areas: (1) Morelandia ranch, km 6 on the PA-408 highway, Municipality of Benevides, monthly from May, 1980, to June, 1981, in both primary forest and planted pasture, with a total of 20,190 specimens of 46 tabanid species collected; (2) "APEG" forest preserve on the Guama River margin near Belem, from September, 1982, to December, 1983, with a total of 13,835 specimens of 38 tabanid species collected. The correlation of certain climatic factors with the seasonal abundances of common tabanid species was investigated and statistically significant relations were found for some species with air temperature, relative humidity of the air, rainfall, insolation, evaporation potentiality or light intensity. This research provides baseline data for future studies of strategies to control these important pest and vector horsefly species.