It's Not a Bird.

Thursday, February 27, 2025

Today’s special animal friend is the Tarantula Hawk, hundreds of species of spider wasps in the genera Pepsis and Hemipepsis. Insects, that is. Pepsis grossa, a particularly large specimen, is the state insect of New Mexico. They were also a band from 1998 to 2005. Atmospheric!

Many species of tarantula hawk wasps are over 2 inches long, making them unusually large. They have shiny, blue-black bodies and colorful wings. Some species have rust-red wings, while others are bright orange or black with blue highlights. The colors inform potential predators that attacking will be risky. They have long legs with hooked claws, the better to grapple with an attacker or tarantula, and their long stinger delivers one of the most painful insect stings in the insect world.

You may wonder how they figured this out. There is a thing called the Schmidt Sting Pain Index, developed by Justin O. Schmidt, an entomologist in Arizona. It grades sting pain on a scale of one (least painful) to four (most painful) with specific descriptions of the precise nature and duration of each sting’s pain. Schmidt experienced the stings himself rather than making a graduate student do it. There is also a “lethality scale” for bites and stings; the tarantula hawk is fairly low on this scale: a 38 out of about 200, with a honey bee sting rating 54.

Adult tarantula hawks feed on nectar and fruit. They are known to become intoxicated and erratic after consuming fermented fruit juice. Males will sit on top of a flowering plant, keeping an eye and olfactory organ out for a reproductive female passing by. (Weirdly, an unfertilized egg will produce a male, while a fertilized egg results in a female.) A male wasp with a good spot will defend it all afternoon. These wasps are active in the daytime and seek shelter at night or in unusually hot weather.

Female tarantula hawks (and spider wasps more generally) have a parasitic relationship (one species benefits while the other is harmed) with a spider. A female with an egg will sting a tarantula between its legs, paralyzing it. She drags the spider to a burrow, lays an egg on its abdomen, and covers the burrow. When the egg hatches, the larva burrows into the spider's abdomen and begins eating the spider's innards, avoiding the vital organs as long as possible to keep the spider alive for several weeks. (I hope my spider-hating readers are enjoying this.) Eventually, the larva pupates, emerges as an adult wasp, and digs out of the burrow to complete its life cycle.

These insects are found throughout the southern United States, Mexico, the Caribbean, and parts of South America. In the United States, the main predator of the tarantula hawk wasp is the roadrunner.