Sunday, August 9, 2020


Pepsis sp. Coronado National Forest, Arizona. 30 Aug 2015. Netta Smith photo

     Tarantula Hawk, what a crazy name for a wasp! Well, I want to tell you all about how this fascinating insect got its name. The several hundred species of Tarantula Hawks (most in the genus Pepsis) have a global distribution at lower latitudes and are common in the Southwestern United States. First of all, the wasp strikes an intimidating figure, to say the least. Most species are metallic blue-black, with orange or black wings. They are up to 5 cm long and have a stinger up to 7 mm long in the largest species. This stinger packs such a punch that the Tarantula Hawk has the second most painful sting of any insect (it is second only to the tropical Bullet Ant). One researcher described it as " . . . immediate, excruciating, unrelenting pain that simply shuts down one's ability to do anything, except scream. Mental discipline simply does not work in these situations."


Pepsis sp. with spider. Big Bend National Park, Texas. 11 Nov 2007. Netta Smith photo

The wasp gets its name from how it raises its offspring through an effective form of parasitism. When a female Tarantula Hawk is ready to lay an egg, it flies out in search of a tarantula or other large spider. When one is located the wasp stings it, paralyzing it so it cannot move (unfortunately for the spider, things don’t get much better from here). The wasp drags the spider back into a specially prepared burrow and lays a single egg on the spider’s abdomen, then covers up the burrow entrance. When the egg hatches, the larva burrows into the spider and consumes it from the inside out, making sure to leave vital organs untouched for as long as possible to keep its host alive. The larva pupates and develops into an adult, and then when the adult emerges from the pupa, it bursts out of the spider’s abdomen and flies off to continue this fascinating life cycle of parasitism.


Pepsis sp. with tarantula. IguazĂș, Argentina. Nov 1995. Dennis Paulson photo


Fun Fact: these wasps are actually nectarivorous, meaning that they feed on flowers and fruits and only hunt in order to find tarantulas to parasitize.


Sean Grealish

Nature Blog Network