Montana Public Radio

Bug Bytes: Tarantula hawk - Pepsis wasp

Jun 15, 2020

The deserts of the southwestern United States are home to some remarkable animals. One kind of creepy crawly often associated with this region is the tarantula. With several species growing to the size of an adult human’s hand, they are certainly impressive.

But what’s even more impressive is an aerial predator called the tarantula hawk. While images of a feathered predator with talons might pop to mind, tarantula hawks are actually wasps.

An examples of Pepsis formosa, more commonly known as the tarantula hawk.
Credit Glenn Marangelo

Depending on the species, these nearly 2-inch-long wasps are metallic blue-black in color with wings that are blue-black, orange or mahogany.

Reported to have one of the most painful stings in the insect world, tarantula hawks are well-equipped to take on their much larger prey. But their venom is not designed to kill. Instead it paralyzes.

Once a tarantula is immobilized, the female tarantula hawk will drag her hapless prey into a specially prepared brooding tunnel where she’ll lay a single egg on the spider’s abdomen. The entrance to the tunnel is then covered, leaving the live tarantula to wait.

Since the spider is still alive, there’s no worry that her offspring’s food will spoil. When the wasp larva eventually emerges, dinner is served.

This gruesome, but amazing, interplay between spider and wasp is not limited to tarantulas and tarantula hawks. There are many other species of wasps that use similar tactics to provide their young with fresh food.

So, for those of you with a bit of arachnophobia, the next time you see a spider, view them with a bit more compassion because they’ve got things to be afraid of too.