Holey Moley

The Hidden Lives Around Us

One of my favorite books that I wish I had written is A Field Guide to Desert Holes by Pinau Merlin. The book is exactly what excites me about being a naturalist: paying attention to the curiosities of the world, particularly ones that many people overlook, and learning from what you see. Plus, the book accomplishes another goal of mine as a writer: to get the reader to go outside and make one’s own discoveries.

Not that we don’t have some wonderful holes in our region, such as the excavations of pileated woodpeckers, holes in the sand created by geoducks, or hollows utilized by pikas, but the desert southwest, where I am writing this from, is a paradise of negative spaces. As Ms. Martin notes, one advantage to the desert is the open habitat. None of that pesky vegetation so prevalent in the PNW gets in the way of a good desert hole.

Years ago while biking near Moab, Utah, where I lived at the time, I came across a gathering of tiny towers. Most were straight, less than an inch long, and had an opening less a quarter inch wide but a few rose and bent at a 90 degree angle, as if the wee turrets were taking a bow. All were made by female Diadasia diminuata bees. Known as digger bees, they survive by harvesting globemallow (Sphaeralcea sp.) pollen. The towers are the entrance to an underground home consisting of tunnels where she lays eggs. If you want to find the males, look for them in the morning: they often spend the night in a globemallow flower, curled around the anthers and stamens. It’s rather darned cute.

Diadasia towers, from flickr by Mike Plagens

Much more common in the desert hole category are antlion pits, made by larva also known as doodlebugs, due to their seemingly random peregrinations. The carnivorous larva construct conical pits, where they wait buried for ants and other meals to enter and fall to the bottom. The antlion larva then grabs the gravity-afflicted bug with scythe-like jaws, injects venom, and eats.

A recent study has determined that antlions “exploit self-stratification in granular media differentially to expose deleterious large grains at the bottom of the construction trench where they can be ejected preferentially.” Duh! In order to “maximize powerful avalanches,” the crafty antlions line their pits “almost exclusively with small slippery grains.” As Dante wrote, "Abandon all hope, ye who enter here."

Antlion pit, larva, and meals. from organicgardeninginfo.com

Another well known set of holes occurs in one of the more famous desert plants, the saguaro. We found a spectacular one on a hike in Catalina State Park. It looked like a veritable cactus condo with dozens of potential homes for animals such as gilded flickers, Gila woodpeckers, elf owls, and purple martins. The first two are the ones that excavate the hole. When this happens the saguaro responds by forming a callus to seal off the bird-caused wound, which creates a “boot,” or living quarters. After the woodpecker or flicker moves out, the boot becomes available for subsequent occupants. (I tried to include a photo or two but had technical issues. Sorry)

Most desert holes are ephemeral, made in a medium such as soil. Saguaro boots, in contrast, last far longer (a well-armed saguaro is well over a century old), meaning untold generations of families could have graced the holes of the saguaro we saw at Catalina SP.

Over the years, I have come to view holes as gateways into worlds of wonders. They may look innocuous, simply a hole in the ground or a plant, but within lies the potential for birth, life, and death. Each is a wonderful example of adaption and evolution, of beings finding their place in world.

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