Activities and physiological states of male and female Tabanus sackeni

Male and female Tabanus sackeni Fairchild (Diptera: Tabanidae) were collected on a road, dipping at pools of water on a road, and at uv-light traps; females were also caught in Malaise traps. Most males at uv-light traps were collected just before sunrise. Most females at uv-light traps were collected in the evening and most had recently taken a bloodmeal. Malaise-trapped females showed a distinct crepuscular peak of host-seeking activity. Crop volumes were variable in these host-seeking females; many had large crops. Crop volumes were small in individuals of both sexes collected dipping or on the road. Many dipping females were gravid. By examining how physiological states and the behaviour of individuals changed according to trap type, we are able to make inferences about the timing and importance of a number of unobserved activities. A link between uptake of water and sugar feeding was apparent and we postulate that mating takes place in the early morning, just before sunrise.