Horse Fly

Female horseflies deliver more painful bites compared to mosquitoes. They employ razor-like jaws to tear and slice flesh, even capable of biting through clothing. After making a wound, they release clot-preventing saliva and proceed to feed on blood for several minutes. Without prompt treatment, these bites can lead to significant swellings, lesions, itchiness, and high fevers.

These flies thrive in diverse habitats including salt marshes, swamps, bogs, and areas bordering ponds, lakes, and streams. Horsefly larvae contribute to the ecosystem by consuming organic debris, insects, small crustaceans, snails, earthworms, and even other horsefly larvae.

Horse flies are potential carriers of equine infectious anemia virus and anthrax among cattle and sheep. They play a major role in transmitting tularemia between rabbits and humans in the Western US. There are suspicions they may transmit Lyme disease as well. In cases of severe infestations, horse flies can cause animals to lose up to 300 ml of blood in a single day, leading to severe weakness or even death.

Due to their prevalence in sensitive wetland environments, controlling horseflies is challenging as certain methods can be harmful to fish, birds, and mammals. While common repellents containing DEET may not completely deter these flies, they could discourage them from biting. To minimize bites, it is advisable to wear light-colored clothing and consider using a cap or hat.