3:00 snapshot #1337

[urbpan]

This pigeon horntail Tremex columba was on my desk when I came in one morning. It was in a urine specimen cup with a note that it had been found in one of the barns. I suspect that this harmless insect was mistaken for a stinging insect and killed. Still I'm glad to get the sample, since I've never seen one of these before.

That alarming-looking spike sticking out the back of the animal is not a stinger but a stout ovipositor the female uses to deposit eggs into wood. In the process she also introduces the fungus Cerrena unicolor into the wood. The fungus digests the wood, allowing the larva to feed on the now-softened substrate. The larva is pursued by yet another harmless yet terrifying-to-most-people creature, the giant ichneumon Megarhyssa macrurus. I've received reports of "four inch long wasps with stingers as long as their bodies," an absurd exaggeration. The giant ichneumon is about two inches long, and that's not a stinger it's an ovipositor. She also drives it into the wood, but deposits her egg directly into the horntail larva. The ichneumon larva eats the horntail larva alive, and the beautiful circle of life continues.