Sheep Nose Bot Fly vs Caribou Bot Fly

Side-by-side species comparison

Attribute Sheep Nose Bot Fly Caribou Bot Fly
Scientific Name Oestrus ovis Cephenemyia jellisoni
Order Diptera Diptera
Family Oestridae Oestridae
Size 10-12 mm 12-16 mm
Habitat Farmland Heathland
Diet Parasites Omnivores
Regions Worldwide Alaska, northern Canada, Yukon, Northwest Territories
Conservation Least Concern Least Concern

Sheep Nose Bot Fly

A parasitic fly that shoots live larvae into the nostrils of sheep and goats while in flight. Larvae develop inside the nasal sinuses, causing distress to livestock.

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Did You Know?

This fly does not lay eggs — it shoots live first-instar larvae directly into the nostrils of sheep while flying past at speed, a method called larviposition.

Caribou Bot Fly

A robust, furry fly that parasitizes caribou and deer in North America. Like its Eurasian relative, it deposits larvae near the nostrils of its host. Adults have vestigial mouthparts and survive entirely on stored energy.

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Did You Know?

Infected caribou may sneeze violently to expel mature bot fly larvae from their nasal passages before the larvae pupate in the soil.