The Spring explosion of color in the Southwestern Deserts

mojave_yucca
Mojave yucca

Escapees from the cold Canadian, Pacific Northwestern, and Mid-Western winters, descend to the Southwestern Deserts for the winter, but by March, you will find a continuous caravan of motorhomes, fifth-wheels, travel trailers, pop-tops, truck campers, and converted busses strung out along the interstates, all heading back north. Just as they flocked in at the beginning of the snowbird season, they flock out now trying to get home for the spring planting of the garden, to visit the grandkids they missed so much, and to see the familiar outbreak of spring at home.

But March is too early to leave the desert. The annual wildflowers don’t begin to bloom until early March, the cacti not until April. By the end of April, when the mercury reaches toward the top of the glass, evaporation has kicked into high gear. The annuals wither and die, and rain will not come until the billowy cumulous clouds burst with the summer monsoons in July.

Yet with the scarcity of moisture during this driest of Arizona’s five-season year, certain plants pick this harsh time to bloom. They must produce flowers to attract the bees, bats, hummingbirds, and butterflies that will pollinate them. They rush to produce seeds in such abundance and with the right timing so that they will ripen and be ready to germinate when the summer deluges drench the dry, parched land.

Flamboyant, neon-colored flowers bring splashes of brilliant color to the desert, sweet, intoxicating fragrances waft through the air, and inebriated pollinators, coated with sticky pollen, flit in an excited frenzy from flower to flower. Night blooming cereus, saguaro, prickly pear, the chollas, agaves, yuccas — all pick this season to bloom.
Some of the desert’s most mysterious and unusual natural events occur during this season, after the snowbirds have disappeared.

For instance, the unusual symbiotic relationship between the southwestern yuccas, the Mohave (photo – top) or Spanish Bayonet (Yucca schidigera), and the Torrey (Yucca torreyi), and with the tiny, white-winged, black-eyed Pronuba moth (genus Tegeticula), the exclusive pollinator of the yuccas. Without them, the yuccas would become another tick mark on the Extinct Species list. Likewise, the Pronuba moth’s survival depends on the yucca, on which she lays her eggs — again, exclusively.

pronuba_moth
Pronuba moth on yucca

In one of the unanswered mysteries of the natural world, the moth’s internal alarm clock rings and she emerges from her cocoon at the exact time that the yucca blooms in early spring, which is always dependent on the weather, not the calendar. The yucca’s blossoms open in late afternoon exposing the ripe pollen.

After mating, the moth arrives later in the evening, enters the flower, and collects pollen from the ends of the stamens, the male part of the flower. Yuccas are self-fertile — they can seed from their own pollen – so she methodically rolls the pollen into a sticky little ball and lugs it over to the pistil, the female part of the flower that sits on top of the ovary. She pushes the ball up to the top of the pistol, to the stamen, where she vigorously hammers the pollen onto the tip. Following her pollination chore, she lays her eggs in the small, green ovary inside the flower.

As the yucca fruit grows, it develops an encapsulating seedpod, which protects the moth’s larvae. After the larvae hatch into tiny caterpillars, they exuberantly feed on the yucca’s seeds, eventually chewing their way through the seedpod and dropping to the ground where they begin the next step of their life. Since there are plenty of seeds there are always enough left for the yucca to disperse in late summer, assuring the continuation of the species.
Neither the moth nor the yucca could exist without the other. The best time to see the moths in action is at dusk. Look for the creamy blooms of a flowering yucca and bring a flashlight.

For more RVing articles and tips take a look at my Healthy RV Lifestyle website, where you will also find my ebooks: 111 Ways to Get the Biggest Bang for your RV Lifestyle Buck (PDF or Kindle), BOONDOCKING: Finding a Perfect Campsite on America’s Public Lands (PDF or Kindle), Snowbird Guide to Boondocking in the Southwestern Deserts (PDF or Kindle), The RV Lifestyle: Reflections of Life on the Road (Kindle reader version), and my newest Boondockbob’s Guide to RV Boondocking (Kindle). NOTE: Use the Kindle version to read on iPad and iPhone or any device that has the free Kindle reader app.

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