Diurnal activity of Chrysops atlanticus: some questions concerning sampling techniques.

Blood-seeking females of Chrysops atlanticus Pechuman begin to respond to a host shortly after sunrise and will remain at a high level of responsiveness until shortly before sunset. Based upon hourly counts, the largest numbers visit the human host shortly after sunrise and shortly before sunset. When counts begin in the afternoon, however, a peak also occurs at 13.00 h. The data suggest that destructive sampling methods may bias the results of studies of C. atlanticus biting cycles and lead to misinterpretations of apparent cyclic patterns. One hour after sunrise appears to be the most favourable time for applying insecticide sprays.