Stumphumping Horntail

On a sunny November sunday, I photographed this wasp at Oaks Bottom Wildlife Refuge in Portland, Oregon. Not entirely sure, but I believe this is a species of horntail. Here in Oregon, lumberjacks refer to these wasps as stumphumpers, or even stump*uckers. Great name for a wasp whose females drill into logs with a drill attached to their behinds.

Horntails, also known as wood wasps, are the misunderstood weirdos of the insect world. They look intimidating, like some kind of tactical wasp, with a long "stinger" jutting from their backside. But they don't sting. That tail is actually an ovipositor, a fancy term for the egg-laying drill bit that females use to bore into dead or dying trees. Inside, they deposit their eggs alongside a fungal cocktail that helps soften the wood for the larva that hatches. Basically, horntails are part carpenter, part fungus farmer.

Despite their frightening appearance, they're harmless to humans and disinterested in our picnics. The larvae tunnel slowly through wood for months, even years, living a life of quiet digestion before finally emerging as full-grown adults. Sometimes, a horntail emerges from furniture years after the tree was cut down. Imagine buying a bookshelf and finding a prehistoric-looking wasp crawling out of it like it just time-traveled through Ikea.

In Oregon and the Pacific Northwest, horntails show up in conifer forests and anywhere dead wood is left in peace.

Taxonomically, horntails belong to the family Siricidae, and they're closely tied to the health of forest ecosystems. While not flashy pollinators or charismatic megafauna, they play a role in breaking down dead trees and making way for new growth.