Gardeners have to deal with a variety of garden insects, pests, and beneficial species alike. Sometimes it’s hard to tell friend from the foe, especially when these creatures are buzzing about. Bees and wasps are familiar and many posses’ stingers that they use for protection or subduing prey. Or stinging the occasional gardener.
One such creature is the tarantula hawk, a member of the spider wasp family. Their name originates from the wasp’s habit of paralyzing tarantulas and other large spiders, then dragging their still-live carcasses into either the tarantula’s own burrow or underground hole or crevice. The female then lays a single egg on the prey, which will hatch in 3 to 4 days. As the larvae grows it will consume its host, feeding first on the non-vital organs to keep its host alive. After several instars, the larvae are ready to pupate at around three weeks old. The pupa stage lasts 15-20 days before the adult wasp emerges.
Known as a parasitoid wasp, this feature developed millions of years ago during the Permian. Obviously, these wasps have had some success with this strategy. One researcher in Arizona found that an average of 13.4 tarantulas were paralyzed by a single tarantula hawk female. And as male tarantula hawks live about two months and females longer, this adds to the success of their warning coloration strategy protecting themselves and their offspring.
Where Are the Tarantula Hawks?
Tarantula hawks are found throughout the world in rainforests, grasslands, and deserts – basically anywhere tarantulas hang out. Worldwide there are between 250-300 species. Large in stature, they may be two inches long. In the United States there are 15 species that occur in just the Southwest. Many have a black or metallic-blue coloration on their body and rusty or black-colored wings. The colorful pattern is also known as aposematic (from the Latin word meaning “signal from a distance”) coloration, and it warns predators that they had better beware the female wasp’s stinger. Males don’t have a stinger. Another difference is that males have straight antennae and females have antennae that curve. The stinger of the Pepsis Formosa (Pepsis grossa) may be up to formidable 1cm in length. Oh yeah, and it delivers one of the most painful insect stings in the insect world.
How painful you might wonder? Entomologist Justin Schmidt has developed the Schmidt sting pain index. As you may imagine, he’s been stung a lot in his line of work. The index runs from one to four, with one being comparable to a fire ant sting. Four belongs to bullet ants and tarantula hawks. Schmidt describes it as “instantaneous, electrifying, excruciating pain.” The only positive is that the pain generally subsides after a few minutes and caution is advised to just lie down and scream if one has been stung, rather than thrashing about madly and inflicting further pain by running into something.
Though getting stung isn’t a common phenomenon unless a gardener or entomologist is trying to handle a female tarantula wasp. Mostly the wasps just do their thing. But the painful, nearly instantaneous sting is the creature’s defense mechanism; the venom is minimal.
Tarantula Hawk in the Food Chain
Adult wasps are nectar feeders, feeding on the flowers such as milkweed, western soapweed, and mesquite. The wasps fly from flower to flower in search of nectar. During the breeding season males engage in “hill topping,” a behavior where the males defend small territories at tree-top levels and watch for passing females to mate with. In addition to feeding on nectar, these wasps may also consume fermented fruit to the point of intoxication. There’s probably a Gary Larson cartoon in there somewhere.
Of course, in nature there is always the check and balance. Roadrunners may dine on these wasps, although the wasp probably isn’t a big portion of the bird’s diet. Also, in nature, there is the mimic rule – if another insect can look like a tarantula hawk, then maybe everyone will leave it alone, too. The robber fly mimics the coloration pattern of the tarantula hawk, relying upon the strategy to avoid predation. Whereas, the robber fly has two wings, a tarantula hawk has four, but no self-respecting lizard or bird predator is going to count wings.
In a show of support for these creatures, New Mexico school kids from Edgewood Elementary helped get the tarantula hawk selected as the New Mexico State Insect in 1989. They had chosen three different insects for the honor, sent ballots to other schools statewide, and picked the winner with the stinger.
So, if you happen to see a tarantula hawk in your garden, sipping nectar or hunting on the ground, give it some space and let it do what it does best.