Thursday, June 30, 2011

Tarantula Hawk

If the population of Pepsis wasps (Pepsis formosa) this year is any indication, tarantulas will be an endangered species! 

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They seem to be everywhere, covering trees, seeking shade and nectar.  With it’s blue-black body and bright, iridescent orange wings, this large wasp cannot be missed.  Pepsis wasps are also known as tarantula hawks for their habit of preying on tarantulas – not for their own food, but for that of their larva.  The female Pepsis wasp seeks out tarantulas, either on the ground or by coaxing the spider out of its burrow.  She then stings and paralyzes the tarantula, drags it into a burrow, lays an egg on the tarantula and seals the burrow.  Upon hatching, the wasp larva has a ready-made meal in the still-living tarantula.  Gruesome?  Perhaps, but it is just part of the daily struggle to survive by every creature.  After about 30 days, the wasp larva will pupate and later emerge as an adult. 

Desert Encounter

Although there are 15 species of Pepsis wasps in the U.S., P. formosa is the most common in Tucson.  The warning coloration (aposematic) lets potential predators know to beware!  Eating this meal will be painful!  Although they are not aggressive, the sting is known as the most painful of any insect in the U.S.  Two predators who ignore this warning and successfully prey on the tarantula hawk are roadrunners and bullfrogs.
Most commonly seen in the summer, even Pepsis wasps will avoid the hottest part of the day by gathering in cool, shady areas, such as large, leafy trees or shrubs.  The adults feed on pollen and nectar and huge concentrations of them descend on flowering soapberry trees, Mexican crucillo bush and other desert species.

Male Pepsis wasps have been known to engage in ‘hilltopping’ – perching on high sites to watch for receptive females.  Remind you of anyone?  Generally, males might live 2 months, while females have a longer lifespan. 

I’m rooting for the tarantula to escape the fate of meeting a Pepsis wasp, but the huge population of the wasps this year does not bode well for the spider. 

Tuesday, June 7, 2011


It's June.  The mercury is pushing its way over the 100° mark, the cicadas are playing their tune,

rain is but a distant memory, humidity is so low the air practically crackles.  And Arizona is on fire.San Pedro,ASDM 034
Really, literally. The smell of wood smoke wafts on the morning breeze and the mountains that ring our valley are obscured by the smoky haze. Each day seems to bring news of a new fire, and now two major national forests, Coronado and Apache, have been closed. Completely closed. To camping, picnicking, bird watching, fishing, hiking, driving, escaping the heat or just enjoying the beauty and solitude of nature. Closed.  We consider ourselves lucky to live in a part of the country where tornadoes, hurricanes and blizzards are non-existent, floods a rarity.. But, boy, do we have fires!  In the beautiful White Mountains of northeastern Arizona, many small communities are being evacuated, people leaving without ever knowing whether they will see their homes or businesses again. 

In my yard white-winged doves have taken over the feeders, the yard and every conceivable nesting spot, annoying me from morning till night with their flapping, courting, mounting, cooing, grunting. Their arrival from Mexico in the spring is often the first hint that summer is not far away.  When the last one leaves in October, we breathe a sigh of relief.  Not only that we have survived another summer, but that other birds may now enjoy the yard in peace. 

The joys? Yes, there are joys. Diving in the pool after a sweaty walk. Floating around with my morning coffee in hand.

Sitting on the patio in the waning light watching the nighthawks swoop down on unsuspecting insects, listening to the sounds of quail bedding down, and seeing the first bat flutter by.  Eating fresh tomatoes from the garden. 

At the Desert Museum, the crowds have dwindled, in size but not in enthusiasm.  I’m always struck by the number of visitors from northern Europe during our hottest months.  They impress me with their tolerance, even enjoyment of the heat, their deep interest in the desert, their adventurous spirit and their excellent command of the English language. 

We bide our time until the promise of the monsoon rains becomes a reality, when the desert comes out of its torpor and once again springs to life.  There are those who will complain about the humidity and the bugs.  Not I.  Instead I will revel in the big, puffy cumulus clouds, the dramatic storms and the new life all around.  Until then .  .  .