Species Insects & ArthropodsGiant Ichneumon Wasp

Giant Ichneumon Wasp

Megarhyssa macrurus

UncommonInsect & Arthropod
Illustration of Giant Ichneumon Wasp (Megarhyssa macrurus)

The Giant Ichneumon Wasp is a remarkable parasitoid wasp where the female's ovipositor can reach 5 inches long — among the longest appendages relative to body size of any insect. She uses it to drill through several inches of hardwood to reach the larva of the Pigeon Horntail wood wasp burrowed inside, parasitizing it with her egg. Despite its alarming needle-like tail, the ovipositor is entirely harmless to humans.

Habitat
Deciduous and mixed forests with dead or dying trees
Diet
Larvae: internal tissues of Pigeon Horntail wasp larvae inside wood. Adults: nectar
How common
Uncommon

Best time to see a Giant Ichneumon Wasp

The best time to see a Giant Ichneumon Wasp is May–August, when about 64% of U.S. sightings happen, based on 4,552 research-grade iNaturalist observations.

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