Meteorological factors influencing host-seeking activity of female Simulium luggeri (Diptera: Simuliidae).

The influence of selected meteorological variables on host-seeking activity of parous and nulliparous female Simulium luggeri at cattle bait was studied in central Saskatchewan. Variability in the pattern of diurnal host-seeking probably was attributable to the secondary influence of meteorological parameters on endogenous rhythms that are primarily stimulated by illumination. Although some differences occurred, nulliparous and parous female S. luggeri activity was similarly influenced by the meteorological factors measured. The most important limiting factors were wind speeds greater than 15 km/h, followed by temperatures less than 20 degrees C. When values were outside of these thresholds, saturation deficit, cloud cover, barometric pressure, and illumination became influential. Parous S. luggeri appeared to be more tolerant of dry conditions than nulliparous individuals. Seasonal differences, site location (exposed versus protected), and varied interactions among environmental factors contributed to the inconsistent relationships among meteorological variables and black fly host-seeking activity.