Influence of temperature and water vapour pressure on the flight activity ofSimulium arcticum Malloch (Diptera: Simuliidae)

The effects of temperature and vapour pressure deficit on the flight activity ofSimulium arcticum were defined under controlled laboratory conditions. Optimum conditions of temperature and vapour pressure deficit for flight activity varied with time of exposure to the environmental conditions. By applying polynomial equations for the various response surfaces it was possible to predict the time-dependent, optimal hygrothermal environment for black-fly flight activity. Greatest variability in flight activity occurred just prior to death of the insects. Mortality of flies after 1 h exposures to the experimental conditions occurred only at high temperatures and vapour pressure deficits. With increased time of exposure, mortality increased at lower temperatures and vapour pressure deficits.