Moth Night

Moth Night at the Boyce Thompson Arboretum in Queen Creek last Saturday night attracted not only thousands of insects, but a few dozen naturalists and photographers ranging in age from 4 to 80. Using a pair of mercury vapor lamps mounted in front of a white sheet, entomologists from the Central Arizona Butterfly Association led the crowd in a frenzy of bug identification and admiration. 

The star of the show was a single patient Western poplar sphinx, with its nearly six inch wingspan and thick furry body. Surrounding this moth were dozens of white-lined sphinx, cholla moths, silk moths, five-spotted hawkmoths, tiny variegated tiger moths, and a handsome rustic sphinx, all fluttering in the bright lights. 

Western Poplar Sphinx (Pachysphinx occidentalis)

Beetles clamored to the scene by the dozens, including june beetles, blister beetles, mesquite beetles and click beetles. Cicadas, grasshoppers and bright green katydids also showed up. My favorite were the ant lion adults, elegant beasts with long lacy gray wings, and a pair of gracefully curved, thick, glossy antennae. Close encounters with three species of snakes and dozens of bark scorpions shining under black lights made this a 5-star event worth repeating in our own back yard. Next frivolous purchase: a mercury vapor lamp.

Ant Lion Lacewing 

Crack Climbing

It might seem like life is over once a pond dries up, but mud cracks are moist shady refuges for all kinds of life. Seeds take root, mosses grow and new toads explore these tiny canyons. 

Water Tigers

Water tigers live in ephemeral pools, devouring tadpoles, fairy shrimp, mosquito larvae and anything else it can grab with its jaws. These 2-3 inch long larvae of predaceous diving beetles are some of the most vicious predators in the desert suburbs, sucking the guts out of their prey and then disposing of the empty carcass. There are about a dozen species of predaceous diving beetles in North America, named Dytiscus in Latin, which means "great diver." 

My first encounter with a water tiger was here at a pond in Skunk Creek, just east of I-17 near the pedestrian bridge north of Jomax. Monsoon storms in late July this year revived myriads of critters that wait patiently in a dormant phase for water to return to the desert. When I first saw the dim outline of the larvae swimming in the murky water, I thought it was a small fish...but there are no fish in this usually dry wash. We captured one with a net and found that it had six jointed legs near its fearsome jaws, tipping us off to its identity as an insect. 

At rest, the water tiger will lift its rear end to the water surface to breathe through a pore or spiracle at the tip of its abdomen. Like their adult form, a large flat beetle, they are elegant and rapid swimmers. The larvae will pupate in the mud once the pond begins to dry, emerging as an adult when the next storm cycle revives the ponds it lives in. We never saw any adult diving beetles, but did witness plenty of water tigers prowling in the pools. 

Mexican Bird of Paradise

Mexican Bird of Paradise (Caesalpinia pulcherrima) lights up the Valley in mid-summer with flaming orange flowers. These plants in the Bean family (Fabaceae) have been part of world wide horticultural trade for so long that no one knows exactly where the first wild populations were discovered. Medicine men in Suriname have been using the plant for centuries, so this may be a clue to its origins.   It is also the national flower of Barbados, and displayed on the royal flag there, another clue to its native roots.

In the Phoenix area, Mexican Bird of Paradise provides welcome relief in the sometimes drab urban landscape, thriving along highways and industrial areas wherever there is a reliable drip system. Hummingbirds, carpenter bees and honeybees are frequent visitors to the flowers, serving as pollinators. The resulting bean pods produce hard seeds that are toxic enough to induce abortion in early term pregnancy, which was sometimes advised by the aforementioned South American medicine men.