Diurnal activity of biting flies in southern Alberta

Biting flies are recognized pests of livestock chiefly through their ability to transmit diseases but can also become a nuisance if they are in abundance. In order to find out the diurnal activity of biting flies, a study has been carried out at two locations in Southern Alberta during the summer 2011. Three types of light traps where a black light (UV) trap and black light traps baited with CO₂ at two release rates (300ml and 1000ml/min simulating output of a calf and a fully grown cow) have been used. Biting flies were crepuscular to nocturnal in their activity reaching a peak activity around midnight but extremely rare during the day with the exception of Tabanids which are generally day fliers. Black light traps baited with CO₂ consistently trapped more biting flies than unbaited traps. Black light traps baited with CO₂ can be effectively used for monitoring the activity and abundance of biting flies. We are currently investigating if this diurnal activity is reflected in their biting rates in the presence of live animals.