Wild Thing: Tarantula Hunter
While these wasps may frighten tarantulas, we have little to fear except a painful sting.
By Ben Hutchins
One of the most conspicuous of Texas’ invertebrates, tarantula-hawk wasps (genus Pepsis) are also one of our most fascinating. These big wasps could certainly be described as beautiful with their iridescent, blue-black bodies and their wings and antennae that can be metallic black, orange or red. What’s most interesting about these wasps, however, is their namesake behavior: hunting tarantulas.
I admire any hunter that specializes in prey larger than itself, particularly if that prey has the substantial defensive weaponry of a tarantula. But the tarantula-hawk wasp takes on the challenge without fear, not only hunting tarantulas at the ground level but also being so bold as to enter occupied tarantula burrows, forcing the spider to the surface for an attack.
If you are lucky enough to see the battle, settle in and take advantage of a rarely seen show.
After a tense face-off, the tarantula-hawk wasp makes its move: darting under the tarantula and biting a hind leg while using its own hind legs to hold the tarantula’s fangs out of biting range. Then, in a bold wrestling move, the tarantula hawk flips the tarantula on its back and delivers the coup de grace: a sting, usually at the base of the first leg (a veritable chink in the tarantula’s armor) that paralyzes the tarantula in seconds.
Then the tarantula’s day gets even worse. The immobilized but still-alive tarantula is carried back to a burrow, where the tarantula-hawk wasp lays a single egg. Like a tomb, the burrow is then sealed until the egg hatches, and the wasp larva begins to feast on the living tarantula. Although chances for survival are slim, all hope is not lost for the tarantula. In at least one species, if the wasp egg does not hatch, the venom will eventually wear off, allowing the tarantula to make a full recovery.
Aside from their behavior toward tarantulas, adult tarantula-hawk wasps are, for the most part, docile vegetarians, feeding primarily on nectar. About 13 of the 250-plus species of tarantula-hawk wasps occur in Texas. Body lengths typically measure up to 2 inches, though the largest of the South American species can reach lengths up to 2½ inches.
They are easily observed up close, being active during the day, particularly morning and evenings, when females can be found engaged in a fast-paced search for prey, apparently unthreatened and unafraid of humans or any other would-be predator.
Justin Schmidt from the University of Arizona hypothesizes that this confidence has arisen from the female tarantula-hawk wasp’s spectacular ability to inflict pain. Schmidt is well qualified to make this claim: As creator of the Schmidt sting pain index, he has been stung by more species of pain-inducing invertebrates from around the world than most of us care to think about. On the Schmidt sting pain index, tarantula-hawk wasps hold an infamous distinction as one of only three insects to attain the highest possible rating of 4 or “traumatically painful.” For perspective, the rather aggressive red wasps (Polistes carolina and Polistes exclamans) that are common throughout much of Texas get a 2, merely “painful.”
Schmidt has described the pain of the tarantula-hawk wasp as “immediate, intense, excruciating, and totally debilitating. The pain is so debilitating and excruciating that few, if any, can maintain normal coordination or cognitive control” if stung.
Despite the sobering warning, humans have little to fear from tarantula-hawk wasps. They don’t show unprovoked aggression toward humans, and in the unfortunate event of a sting, the pain completely subsides after a few minutes, leaving no permanent damage.
Their bold coloration and charismatic swagger make tarantula-hawk wasps an entertaining and welcome addition to the Texas landscape.
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