Horse bots, or horse flies, are larger than regular house flies.
Horse bots, sometimes called horse flies, are about the size of a honey bee. They zoom around horses, as well as mules and donkeys, sometimes frightening the animals and creating havoc. The flies are annoying, but the bigger problem is the tiny eggs they lay in the animal's hair. These unwelcome deposits are called bot eggs.
Bot Eggs
The bee-size horse bot looks like it has a helmeted head.
There are three species of horse bots and each species attaches its eggs in a different place on the host animal's body. Common horse bot eggs are usually found in the hair on the horse's fore legs, but also on the flanks, the outside legs or the mane. Nose bots deposit their eggs in the hair under and above the animal's lips. The long hairs underneath the jaws are usually where you'll find throat bot eggs. Horse bot females lay anywhere from hundreds to 1,000 bot eggs during their lifetimes, depending on the species.
Life Cycle
Horse bot eggs can make an animal miserable.
After the bots hatch, a 2-to-5 day incubation period for common horse bot eggs, they enter the host animal's mouth. The larva spend about 3 weeks in the soft tissues of the tongue, gums and lips of the animal before migrating to the stomach or small intestine. Once there, they attach themselves to the organ lining, where they stay until they are expelled in feces about 7 months later. The expelled larva burrow into the soil where they pupate for 2 weeks to 2 months before emerging as adults. Horse bots can be transferred to humans through contact with a horse. Although the larva can hatch in a human mouth, they will die after a few days.
Effects
Bot larva in the stomach or intestines of the host animal are more than just an annoyance. They can damage the lining of the organs and cause various gastrointestinal disorders, such as preventing the passage of food. In addition, horses spooked by the flies while they are laying their eggs can do harm to themselves or people around them at the time.
Controlling Bot Eggs
Clipping hair or sponging off nits are not effective ways to control horse bots eggs.
Look for eggs in the mule or horse's coat, even if you don't notice bot flies in the area. Since most of the pest's life cycle occurs inside the horse, careful checking for nits or eggs can alert you to their presence. Internal insecticides are necessary to effectively control the egg infestation. Laws regarding which pesticides are legal differ by state and region, so consult a local veterinarian or agricultural office for guidance.
Tags: host animal, eggs they, horse bots, Horse bots, horse flies