Nature's Neighbors ~ Tarantula Hawk

This neighbor is neither a tarantula, nor a hawk, but is a very interesting insect. Both genera Hemipepsis and Pepsis are called "Tarantula Hawks".  They are indistinguishable in the field and have very similar life histories.  Four species of Hemipepsis and 15 of Pepsis are found in North America.  At least nine different species of the wasp inhabit the desert lands of the southwest. Pepsis formosa, and Pepsis thisbe, the most northern ranging, are probably the two most common.  

Tarantula Hawks occur wherever tarantulas are found and females give these wasps their common name.  Like all members of this genus, they require a spider to serve as food host for their larvae.  Male wasps engage in a behavior called "hill-topping," where they perch on taller vegetation or high points. They are strongly territorial at these sites because of the good view of the surrounding area and in particular, of females which may be receptive to mating.

Body length measures up to two inches, and are metallic blue-black with wings that are rust or mahogany, or occasionally black, in color.  This is another group of insects which have aposematic coloring – that is, conspicuous bright coloring – which warns potential predators that this is a meal that might be more painful than it is worth.  Only a few animals, Greater Roadrunners being one, eat tarantula hawks.

A female wasp finds a tarantula by running across the ground to locate a burrow to draw a spider out of, or she may also encounter a male tarantula in the open during his search for a mate.  Once stung, the tarantula is paralyzed (not killed) within seconds, and the condition will last for the remainder of its life.   If the wasp found her victim underground, she will drag it back into its own burrow and lay a single egg on the spider’s abdomen, then seal the chamber. If the wasp succeeds in stinging a male tarantula on a mating hunt, she will excavate a burrow, drag the paralyzed spider inside, lay her single egg, and seal the chamber.  After going through metamorphosis, the new adult wasp will emerge from the burrow the following season.

Tarantula hawks are most active in the summer during the day, although they avoid the highest temperatures.  The wasps consume nectar and other sugars, and they have been known to become "drunk" and unable to fly after consuming fermented fruit.  Their stings are considered to be the most painful of any North American insect, but they will ignore you and your pets, and may be observed at a very close range if they are left unmolested.