Gasterophilus intestinalis larvae are obligate internal parasites. Adults are free-living and non-parasitic. The preferred hosts of this species are horses, giving it the common name of “horse bot fly”. ( Cogley and Cogley, 2000; Lyons, et al., 2000; Roberts and Janovy, Jr, 2000) Larvae feed on the blood of their host.

What is Gasterophilus intestinalis in horses?

Gasterophilus intestinalis. Gasterophilus intestinalis, also known as horse bot fly, is a species of insect of the family Oestridae, and is found worldwide. The adults, which have a bumblebee-like appearance, are prominently active in the summer. G. intestinalis is primarily a parasite of horses, mules and donkeys.

What is the life cycle of Gasterophilus?

Life cycle The first stage: During the summer months, the full-grown Gasterophilus lays the eggs over the hair, face, and extremities of their future host (these eggs are laid on different portions of the body according to the various Gasterophilus species).

What does G intestinalis look like on a horse?

G. intestinalis is primarily a parasite of horses, mules and donkeys. The eggs of G. intestinalis are pale yellow in color, and 1–2 mm (0.039–0.079 in) long. The larvae are yellow or tan. Adults, which are 10–15 mm (0.39–0.59 in) long, look superficially like hairy bumblebees, with a noticeable ovipositor at the end of the abdomen.