Hornet Robber Fly vs Reindeer Warble Fly

Side-by-side species comparison

Attribute Hornet Robber Fly Reindeer Warble Fly
Scientific Name Asilus crabroniformis Hypoderma tarandi
Order Diptera Diptera
Family Asilidae Oestridae
Size 18-28 mm 13-17 mm
Habitat Grasslands Heathland
Diet Predators Omnivores
Regions Europe, North Africa Scandinavia, Finland, northern Russia, Siberia, Arctic Canada, Alaska
Conservation Near Threatened (declining in northern Europe) Least Concern

Hornet Robber Fly

Europe's largest robber fly, a hornet mimic with a yellow-and-brown body that hunts dung beetles on grazed pastures. Females lay eggs in animal dung where larvae develop as predators.

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Did You Know?

It specifically hunts dung beetles, and its larvae develop as predators inside cow pats and horse droppings.

Reindeer Warble Fly

A stout, furry fly that parasitizes reindeer and caribou. Females dart at reindeer to lay eggs on their legs. Larvae burrow through the skin and migrate through the body, creating warble lumps under the back skin.

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Did You Know?

The buzzing of this fly causes reindeer to panic and stampede, and heavy infestations can reduce a reindeer's body weight by up to 25 percent.