Symbiont-free
Guides
Xeris spectrum
wood wasp, horntail
Xeris spectrum is a large horntail or wood wasp in the family Siricidae, notable within its family for lacking the fungal symbionts that other siricid wasps use to aid larval development in wood. Females possess a powerful ovipositor used to drill into coniferous trees and deposit eggs beneath the bark. The species is widespread across Europe, Asia, Africa, and North America, where it develops in the wood of fir, spruce, pine, and larch. Development from egg to adult takes several years, with larvae emerging in two distinct cohorts—some in summer alongside other wood wasps, others the following spring. The species is considered a timber pest due to larval tunneling that degrades wood quality.