Thread-Waisted Wasp

Originally I thought this was some sort of fly. Then I thought it was a wasp. Then I thought it was a wasp mimicking a fly. /r/insects didn’t know what it was. Months later, while searching for Polistes wasps on google, I scrolled past a picture of a similar species of sand-digger wasp, and — aha!

Sphecid wasps include sand wasps, mud daubers, and other thread-waisted wasps in a number of subfamilies. This looks like a digger wasp, one of 130 species active all over the world. According to the University of Florida, there are five species of Sphex wasps active in Florida; the one that matches this one most closely is Sphex dorsalis.

Digger wasp females tend to dig small burrows, in which they store paralyzed, live insect prey, with a single egg laid on them. The burrows are then sealed, and, once the egg hatches, it has a source of fresh food until it is ready to dig itself out of the burrow. (That’s probably why this wasp has those barbs on its legs — the same barbs I thought meant it was a fly.) During a single evening, a female wasp may dig as many as six burrows, each with a separate, macabre “cargo” and a single egg.

Digger wasps appear to exhibit complex behavior as they locate prey, attack and immobilize it, dig a burrow for it, drag it into the burrow, lay an egg on it, and close the burrow again. Experiments have shown that these apparently complex behaviors can go easily awry if the sequence gets disrupted in any way — if the prey is missing antennae, for example, the wasp will be unable to drag it into the burrow. It does not seem to think of grabbing a leg or any other appendage to drag the prey.

Leave a Reply

Your email address will not be published.