As formidable as the common name is, the tarantula hawk wasp is not all that fearsome to look at though it is one of the larger wasps. The common name "tarantula hawk wasp" refers to several species of the genera Pepsis and Hemipepsis, wasps that happen to be parasitic feeders of the tarantula spider. In North America, there are said to be 18 species of Pepsis and three species of Hemipepsis tarantula-hunting hawk spiders.
Often black in color, the tarantula hawk wasp is a common desert wasp of the southwest, but it can be found anywhere the tarantula lives. As its name suggests, this wasp preys on tarantulas, in much the same way a hawk preys on rodents. Although the sting of this wasp is said to be the most painful of any insect found in North America, it is not aggressive and rarely stings humans. It is, in fact, much more dangerous to tarantulas—paralyzing them in order to feed them to their young. If you're squeamish around spiders, the tarantula hawk wasp is an insect you might even cautiously welcome—provided you were willing to be careful.
Tarantula Hawk Wasp Behavior
Up to 2 1/2 inches in length, the tarantula hawk wasp is metallic blue-black in color with blue-black or yellow-orange wings edged in black; it has black antennae and long, velvety black legs with hooked claws. Adults feed on flower nectar, pollen, and the juice of berries and other fruits, but the larvae feed on tarantulas provided to them by the mother.
To capture its prey, the female searches the ground for tarantulas. If the spider is found in its burrow, she will stroke its web, making the tarantula think it has captured prey. When the spider appears to claim its food, the wasp stings it, drags the paralyzed tarantula to her burrow, lays an egg on its body, then covers the burrow. When the egg hatches, the emerging larva feeds on the tarantula, eating the living spider from within in about a month. Within several weeks, the larva will pupate within the host spider, then emerge as an adult wasp.
After reaching adulthood, these wasps feed mostly on the flowers of milkweed, soapberry tree, and mesquite. They are most active in the summer, though tend to go dormant during the extreme heat of mid-day. Stings normally occur by accident when a person brushes against an insect or steps on it. Because these wasps tend to fly low and hunt along the ground for spiders, a person moving barefoot across a lawn without looking down could be at some risk. Tarantula hawks tend to live alone, rather than in colonies. Many do not build nests at all, but instead, burrow into the soil or use natural cavities or the burrows of other insects or animals.
Although the sting of these insects is extremely painful—among the most painful of any animal bite—they are not aggressive creatures and stings to humans are not common. Many pest experts recommend that people simply leave them alone.
4 Ways to Avoid/Get Rid of Tarantula Hawk Wasps
Tarantula hawk wasps have been known to seek cool indoor spaces during the heat of summer days, so it's a good idea to seal all cracks, crevices, and gaps in the structure, especially in the foundation. Ensure that your doors and windows are well-fitted and screens are in good repair. Keep doors and windows shut, especially during the hottest portion of the day.
Watch for Wasps on Foods
When eating or drinking outside, checking food and beverage containers before touching to ensure no wasps have been attracted to them or have landed on the food. The last thing you want is a tarantula hawk wasp sting on your lip.
Be Careful Where You Walk
These ground-hunting wasps can easily be stepped on if you walk across a lawn or other terrain with bare feet. Always wear shoes in areas where tarantula spiders or their predator wasps are present.
Use Carbaryl-Based Pesticide
Though regarded as a last resort, a hawk wasp can be killed with pesticide. First, locate the wasp lair, which will appear as a small hole in the ground, 1 to 2 inches across. Ideally, you will identify a wasp entering or existing this lair.
At night, when the wasp is almost certainly in the hole, pour a liquid carbaryl pesticide down the hole, then immediately cover the opening with a mound of soil to trap the wasp inside. It may take as long as two days to ensure the wasp is dead.
Then, dig up the lair to destroy it and prevent another wasp from taking up residence.
What Causes Tarantula Hawk Wasps?
Tarantula hawk wasps can be present wherever tarantula spiders are found, and wherever the wasps can find their favorite foods—the nectar of milkweed, soapberry tree, and mesquite. These wasps will favor rocky, sandy terrain and naturalized landscapes; they are less likely to be found in cultivated lawns and gardens.
How to Prevent Tarantula Hawk Wasps
To prevent hawk wasps (especially for persons allergic to the stings), avoid landscaping with the plants preferred by the wasps.
Why Should I Avoid Poison on Tarantula Hawk Wasps?
These wasps are so non-aggressive that a crusade to kill them is usually unnecessary. They are rarely found in cultivated gardens or lawns, but rather favor wilder territory where large spiders are more frequently found. Further, poisoning is effective only if you can find specific lairs, and this can be difficult. Pouring toxic chemicals into random holes is not regarded as a very responsible practice. Further, this creature is the state insect of New Mexico, and its method of hunting spiders is of scientific interest. Conservationists often urge that you avoid this creature and leave it to exist peacefully.
Just How Painful Is the Sting?
No question, the sting inflicted from the 1/3-inch-long stinger and toxin it contains is very, very painful. By one index of insect bite severity (the Schmidt scale), it ranks at #4 on a 1-4 scale. By contrast, the common wasp is regarded as a #2 severity sting.
The maximum #4 rating is shared only by the bullet ant. Thinking clearly is said to be impossible for the five minutes or so of most intense pain experienced when stung by a tarantula hawk wasp.
The sting of the tarantula hawk wasp is almost never fatal except if you have an allergy. But it is extremely painful, and you can limit the suffering by applying Benadryl or another topical cortisone product to the sting site. Apply an ice pack to minimize swelling and numb the skin area. Then wash the area with an antibacterial soap. If, however, you experience any swelling of the throat or problems breathing, seek medical help immediately.
The severe pain generally lasts only a few minutes, though you may have some residual tenderness for up to one week.