Horse Flies

Horse Flies hut you, your animals and your horses. Horse flies are much larger than house flies, fly more slowly and make a loud buzz. Horse flies are in the fly family Tabanidae, which includes the deer fly. Both horse and deer flies buzz on approach (deer flies’ whine is higher pitch), horse flies aim at bare skin below the knees, deer flies aim for your neck like a vampire. Horse flies like to fly up under neath the belly of the horse where the horse's tail cannot swat them away. There are about 4,500 Tabanid species worldwide – 350 in North America. They’re found around the globe except for Hawaii, Greenland, Iceland, and the Polar Regions. Horse flies often are found around barns, pastures, farms, and permanent wet/moist lands because that’s where their somewhat aquatic offspring live.

Female horse flies drink the blood of mammals to obtain the protein needed to make her eggs. Typically, the female bites horses and other large grazing animals that are not agile enough to swat them away. After eating and digesting her blood meal she is ready to produce eggs.

She lays her eggs in clumps that may contain up to 1,000 eggs in several layers. Egg masses are glued to vegetation, rocks, twigs, etc. over the water. The tiny larvae are equipped with a spine that helps them exit the egg, and when they hatch, the larvae fall into the moist ground. There they stay for several summers, especially in the north, feeding on small, soft-bodied insects and crustaceans, subduing them by biting them and injecting a venom. 

The Male horse fly feeds on nectar and pollen and do not have the equipment to bite. Females drink nectar, too, but they also need a blood meal and generally ambush passers-by, zeroing in on large, dark-colored objects that give off a cloud of CO2.

FOR EVERY FLY YOU TRAP, THERE IS ONE LESS FEMALE FLY TO BITE AND LAY 100s of EGGS.!