Another half an hour to kill while my son had guitar lessons. A trip to Devil’s Rock was the obvious choice. I saw a lot of wasps flying around, but they were very tough to photograph in flight.
I followed this particular wasp for almost the entire half hour. The long ovipositor identifies her as a “she”; she’s probably a Braconid wasp, and probably of the genus Atanycolus. No surprise, she spent a lot of time walking around a rotting log; no surprise, I followed her everywhere she went, trying to get a shot of her laying her eggs in the wood. Sadly, it was no dice.
What was she doing? While I don’t know anything about Atanycolus in particular, I have some general ideas of Braconids and Ichneumonids. They are parasitoids, and try to lay their eggs in beetle grubs, caterpillars, and other insects. Some Atanycolus species are wonderful at controlling the Emerald Ash Borer, which would mean a lot, since that is a major pest of our forests.
The beetles react by laying their eggs deep in the wood. The wasps fight back by growing long ovipositors and developing the almost supernatural ability to detect grubs deep in the wood and managing to aim their ovipositors directly into the grubs.
They tend to walk along the wood, tapping with their antennae, listening for sounds that indicate that there is something in the trunk that’s not wood, and searching for the smell. Being able to drill into the wood is very impressive — they’ve evolved to actually have metal in their ovipositors. Yes: you can call them bionic.
Here’s a closeup of the ovipositor, a little hairier than I expected!
It’s sometimes not pleasant to think of parasitoids laying their eggs in living creatures. But let’s not superimpose human standards onto these wonderful animals, and instead take the time to admire their amazing abilities.