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Gifts from My Daughter

© B. J. Barton

Daughter, Mary, has given me some very nice gifts--some of them useful and needed, some for pure enjoyment. Some of them come in a plastic cup with a lid and small holes poked in it, and could be classified as "interesting." I always open these carefully. One day she came in from her car with one of these cups and explained, "I found it on the windshield. I'm not sure what it is. It looks sort of like a wasp, but not quite."

I got one of my capture jars (a quart glass jar and a lid with air holes) and carefully held it over the plastic cup as I removed the top. The insect that eventually transferred into the jar certainly did resemble a wasp, but it didn't have the slender waist of a wasp. It had a brown head and thorax with a black and yellow striped abdomen. Its six legs were brown, the back pair larger with black spots on the first section, It had a pair of brown antennae protruding from between its eyes. Altogether, it measured a bit over an inch long.

I didn't know what it was, either, so I headed for my small collection of field guides, and I got lucky with the very first one. There on page 103 of my Audubon Society Pocket Guide: Familiar Insects and Spiders was a really great photo of my mystery insect. It was a Pigeon Horntail (Tremex columbus), a member of the order Hymenoptera, which includes wasps, bees, and ants. The good news about this one is that it doesn't sting, and it's vegetarian. Not such good news if you are a tree, however. One reason it wasn't a familiar creature to me is that Pigeon Horntails spend most of their life cycle under the bark of a hardwood tree, either in the egg stage, the larva stage, or the pupa stage. In late summer, they may be seen as an insect for a short time when they come out to mate and lay eggs.

The female has a long ovipositor on her tail end (so the specimen I had appeared to be a male) and she actually pierces the bark of a hardwood to lay eggs in the wood along with a wood-decaying fungus. The fungus softens the wood and makes it easier for larva to digest. This, of course, weakens the tree. The piercing is so hard and deep that the ovipositor may be stuck in the wood and the female dies there, but her insect chore is ended and she is scheduled to die now anyway. The eggs hatch and the larva tunnel their way around in the tree, digesting wood for a while, then they pupate. Almost two years after the eggs are laid, the new crop of insects chew their way out, each emerging from its round hole with a mission of mating and laying eggs.