Ochraceum Black Fly vs Throat Bot Fly of Horses

Side-by-side species comparison

Attribute Ochraceum Black Fly Throat Bot Fly of Horses
Scientific Name Simulium ochraceum Gasterophilus nasalis
Order Diptera Diptera
Family Simuliidae Oestridae
Size 1.5-3 mm 11-15 mm
Habitat Mountains Farmland
Diet Blood Feeders Omnivores
Regions Mexico, Guatemala, southern Mexico, Central America Worldwide wherever horses are kept
Conservation Least Concern Least Concern

Ochraceum Black Fly

A small orangish-brown black fly that is the principal vector of onchocerciasis in Central America and southern Mexico. It breeds in small, fast-running mountain streams. Biting activity peaks in the early morning and late afternoon in coffee-growing regions.

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Did You Know?

The Americas are close to eliminating onchocerciasis thanks to mass ivermectin distribution targeting this vector's parasite.

Throat Bot Fly of Horses

A yellowish-brown bot fly that lays eggs under the jaw of horses. Larvae migrate to the area between the teeth and gums before traveling to the pyloric region of the stomach and duodenum. It is one of the most common horse bot flies worldwide.

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Did You Know?

Unlike other horse bots, this species' larvae prefer the duodenum over the stomach, a unique niche among Gasterophilus species.