The Bot Fly is an ectoparasite, which can easily be mistaken for a Bee buzzing often found buzzing around your horse’s head, and lower legs. These flies utilize our horses as a living host, and are capable of laying 100’s and sometimes 1000’s of eggs on your horse’s coat in their short week long adult life span.
There are two primary types of Bot Flies that affect our equines:
- G. intestinalis can lay up to 1,000 pale-yellow eggs which are typically found on the horse’s forelegs and shoulders. The moisture and friction from the horse’s licking itself cause the eggs to hatch in about seven days. After hatching, the larvae are licked into the mouth, at which point they work their way to the horse’s digestive tract.
- G. nasalis can lay up to 500 yellow eggs typically found around the chin and throat of the horse. These eggs are not dependent on the horse licking them to hatch, instead they burrow under the skin to the mouth, wandering through it for about a month before migrating to the horse’s stomach.
Life Cycle:
Bot Fly’s get to work in early summer depositing their eggs during the 7-10 day window of their fertile adult life. Once the eggs have hatched they migrate in their unique ways to the horses stomach, and digestional tract. Here they will imbed and attach to the stomach wall, and intestinal tract to grow and develop. At this point the bot fly will remain attached to its host for 8-10 months. These larvae will remain in the stomach until the spring, and when fully developed will be passed out through faces. Once released they will pupate on the ground, and emerge as fully fledged adult flies 1-2 months later. Once the fly emerges from the pupa, it will find a mate, and within hours the female fly will begin looking for it’s potential host or in most cases hosts.
What are the symptoms of a Bot Fly infestation?
The symptoms vary but can include loss of condition, a dry brittle coat, spiking temperature, restlessness, kicking at the belly and lack of appetite. This can also be paired with diarrhea or constipation. Additionally the larvae can cause further issues such as gastritis, stomach ulcers and in severe cases cause colic, and perforation of the stomach causing fatal peritonitis.