Blue Horntail vs Gold Cuckoo Wasp

Side-by-side species comparison

Attribute	Blue Horntail	Gold Cuckoo Wasp
Scientific Name	Sirex juvencus	Chrysis fasciata
Order	Hymenoptera	Hymenoptera
Family	Siricidae	Chrysididae
Size	12–30 mm	7-11 mm
Habitat	Forests	Heathland
Diet	Wood Feeders	Nectar Feeders
Regions	Europe, North America, Asia	Southern Europe, North Africa
Conservation	Not Evaluated	Least Concern

Blue Horntail

A metallic blue-black horntail wasp found across the Northern Hemisphere. It breeds in recently dead or dying spruce and fir trees.

💡

Adults sometimes emerge from milled lumber years later, boring clean round exit holes through flooring or walls.

A brilliant green and gold metallic cuckoo wasp found across southern Europe. It parasitizes the nests of potter wasps and mud daubers.

💡

Its metallic coloration is produced by nanoscale structures in the cuticle rather than pigments, similar to how opals create color.