Bots infect horses in many parts of the country. They have a very
interesting life cycle with the adults resembling a honeybee. The larva in
the stomach look similar to many free-living grubs.
These larva attach to the lining of the stomach and cause a very small
ulcer. When there is a heavy infection these ulcers may join to form a
large ulcer. There are indications that if the ulcer is large enough it
may cause colic.