Diseases carried

• Anthrax
• Tularemia

Vector organisms

• Chrysops (the deer flies)
• Tabanus (the horse flies)

Life Cycle and Control

Tabanids lay their eggs in sheltered areas where they hatch into larvae that will develop in rotting vegetation, mud, damp soil, and some aquatic environments. Development is generally considered to happen far enough underground to make control with larvicides very difficult.

Larval development is a leisurely process. It can take 1-3 years depending upon local conditions, especially the climate, before entering a pupal or chrysalis like stage that takes 5-20 days to develop into into a mature fly.

Tabanid flies prefer bushy or tree environments (coppices, woods and forests) that are damp or swampy. The females feed in bright sunlight using dark moving objects as their targets. They are exophilic and exotrophic, preferring to feed and live away from buildings. They have large mouthparts that can bite through dark clothing and the bite is immediately painful meaning that they will be chased away by a number of victims before they can complete a blood meal. This makes them effective mechanical vectors for disease. They can carry a disease from one animal to another without the pathogen needing to be adapted to the host biology.

There are exceptions to these general rules. Some tabanids develop in drier environments and live in savannah or grasslands, and some are crepuscular (dawn and dusk) or nocturnal (night) feeders.

There are no practical countermeasures against tabanids. Insecticide spraying is relatively ineffective as populations are very dispersed.

Other Countermeasures

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