The case of the shadowy beetle

The windshield of Dave Hawks’ 1994 Toyota 4Runner is splattered yellow, but Hawks doesn’t mind. He’s speeding north on U.S. 395, past Adelanto, Boron and Ridgecrest and running the wipers would only make matters worse. Besides, it’s now a point of discussion.

“It’s all the fat in their bodies,” he says, explaining why this butterfly -- the painted lady -- makes such a distinctive impression. “They need that fat for energy because they have such a long migration.”

Spend time in an entomologist’s company and you make peace with insect juice. But Hawks, a 49-year-old research associate from UC Riverside, isn’t just an entomologist. He’s a coleopterist, a tongue-tangling sub-species devoted to the study of beetles.

Catch him in his native element -- the foothills and mountains of California -- and you’ll find him chasing down a local variety of these bugs, often in the predawn and often in the cold rain.

He will probably be smiling too, for only under these conditions is he able to find the ever-elusive rain beetle, an insect whose mysterious habits might just tell us one day how California, this far-flung edge of the continent, formed and became home to such a wild diversity of flora and fauna.

Hold this beetle in your hands and you’ll stare down nearly 100 million years of evolutionary history, beyond ice ages and the origins of modern man, to the extinction of dinosaurs and the drifting of continents, to a time when the western edge of North America was but a sliver of mountains, these mountains just shy of Nevada, and nothing more.

Now if only rain beetles were easier to catch.

--

Perhaps the best introduction to Pleocoma, as this genus of bugs is formally known, begins at the Natural History Museum in Exposition Park. Step past the dinosaurs and dioramas, take the elevator to the third floor where the Entomology Department houses 5.5 million specimens and pull out Drawer No. 04955.

Pinned to a bed of what looks like white cotton are 100 red-amber and light-brown beetles, no larger than a half-dollar, their exoskeletons glistening with oil, their undercarriages fuzzy with fur. If you pick one up by the head of its pin, you’ll find beneath it a tiny label covered with tinier type.

1-20-57. 5 mi. N. Beverly Hills, Oak Pass Rd., Sta Monica Mts., LA Co., Calif, 1100’, Noel McFarland.

CA Los Angeles Co. Mulholland Hwy. Allenwood Dr. 20 Nov 83 S. Riff

Mulholland Bridge Sepulveda Pass Santa Monica Mts A.V. Evans at street light.

If L.A. ever had a bug worthy of noir, it would be the rain beetle, a critter whose mating habit puts it in the category of the slippery grunion for being both strange and wondrous, a species that emerges from the shadows of nowhere to mate only in the early morning or late twilight hours -- and only during the winter rains.

Or in the case of the species that Hawks is after this afternoon, Pleocoma rubiginosa, in the spring, at sunset and near melting snow, conditions that make today’s outing all the more pleasant.

Hawks hardly needs to add more specimens to his collection, but he relishes the chance to slip out of the lab. He accelerates up Nine Mile Canyon Road just past Pearsonville. The northern stretches of the Mojave fall behind in the rear-view. White patches lie scattered like puzzle pieces on distant peaks.

In 10 miles the road gains 3,700 feet, and at the Chimney Peak Fire Station, he turns onto a dirt road. A meadow is covered with rabbit brush. The sun is warm, and at the top of a small hill, he stops and turns off the engine.

“This should do,” he announces.

--

No one can say why rain beetles prefer to mate under such specialized conditions. Do they warm to the angle of the sun detected deep where they live underground? Do they thrill to the vibration of rain striking the surface of Earth or the dry loam of the forest turning to mud? Are they attuned to changes in barometric pressure?

For a creature that spends most of its life as a lowly grub -- that leggy, waxy comma-shaped denizen of dirt that works the folds of earth, nibbling roots and waiting about 10 years for the moment of pupal transformation when it can fulfill its destiny, become a beetle and live for a few more months underground, waiting for the rain, then mating and dying -- such possibilities are not unreasonable.

Perhaps equally odd is the fact that this seldom-seen bug has been studied as thoroughly as it has.

It all began in 1856. Some gold miners in California had excavated a beetle, stranger than any they had ever seen, and rather than just stepping on it and moving on, they saved it. Then one day John L. LeConte got his hands on it.

Excited at the prospect of a new species, LeConte delivered a paper to the Academy of Natural Sciences in Philadelphia. “A very remarkable insect . . ,” he began, quick to make his mark.

Soon budding coleopterists, eager to test Darwin’s fledgling theories, put Pleocoma on the map, discovering additional species of the bug and attempting not only to explain its behavior but also to identify its place on the Tree of Life in the larger community of beetles.

In recent times, Pleocoma has ridden, Zelig-like, each new wave of science. It was there when plate tectonics and glaciation were talked about in the 1960s, and it was there 30 years later as phylogeny, phylogeography and molecular clocking were batted about.

Entomologists realized that by merit of Pleocoma’s considerable pedigree (perhaps 100 million years) and its niche in the world (only on the West Coast), they were looking at a bug quite unlike the typical June bug that bumbles around any porch light on an early summer evening.

Pleocoma does its own bumbling around, mostly at rural gas stations and rest stops, but what makes this beetle unique is how limited its bumbling is. Only the males fly; the females are flightless and live only underground.

Yet somehow in the course of its long march toward the present, it scattered itself from the foothills of the Sierra Nevada to isolated pockets in northern Baja, along the coast and as far north as the river valleys of Oregon.

For the longest time, no one was certain how.

--

Hawks pops open the hatchback of the 4Runner.

Crammed into the narrow space are the tools of his trade: insect nets, vials and containers, shovels and trowels, gloves, headlamps, 5- and 2-gallon buckets, Coleman fluorescent lanterns, a 1,000-watt generator, a 175-watt mercury vapor lamp, ultraviolet lamps, white sheets, extension cords, lawn chairs, an ice chest, soft drinks, black pepper pistachios, Mrs. May’s Cashew Crunch, three flavors of beef jerky and apples.

He hands shovels to Rebeccah Waterworth and Andrew Ernst, students from the university’s lab, and they follow him up a steep berm into the woods.

Hawks was a teenager in San Diego in the 1970s when he found his calling. He liked to collect things -- stamps, coins, rocks, shells, fossils -- and one day his sister asked for help gathering insects for a biology class. There was no turning back.

A molecular biologist, he spends most of his time extracting DNA from the pinched legs of insects and peering at a computer screen. His funded research is in the realm of parasitic wasps and agricultural pests.

Pleocoma, however, is a labor of love. Constructing the Pleocoma family tree was once tricky business, relying mostly upon the keen eye of a collector who could detect an extra branch on an antenna or a slight variation in color.

Genetic sequencing changed that. Now species, no matter how identical they may seem, can be classified by the unique arrangement of their protein molecules.

In the course of this work, Hawks has helped identify nearly 30 species. His computer-drawn diagrams are dizzying road maps of specification that delineate the evolutionary relationship between each variety of beetle.

Never mind the Tree of Life. These are the Twigs of Life, so finely detailed that Hawks’ mission has something of a divine, if not elegantly mad, nature. Never mind how many angels can dance on the head of a pin, the real question is how many beetles live underground and fly about unseen by man?

--

Hawks and his crew spread out over the hillside. There are no trails, but the forest is open, a scattering of oaks, pinyons and a few digger pines. They step around clumps of sagebrush and see what they’re looking for: pin holes in the forest duff.

Emergence holes for the male beetles, he explains. The location has seen a flight.

They dig at the holes hoping to find a female. Nothing. They dig along the edges of the remnants of snow. Nothing. But in some coyote scat, they discover the hardened shells, the elytra that cover the rain beetles’ wings. The beetles are a delicacy for wandering foragers.

After nearly two hours of wandering and digging and drawing blanks, Hawks and his students return to the 4Runner. He pulls out a folding chair and opens packages of pistachios and jerky, content to wait until sundown.

One hundred million years ago, swells from a western sea lapped against the shores of a lagoon that edged this mountain range. Rivers cut through foothills thick with oak, magnolias, cycads and tree ferns. There were tropical birds and miniature horses, pronghorn antelope, camels and mastodons, and when it rained -- and it rained a lot -- Pleocoma knew it was time to mate.

But geologic time is never static. Mountains lifted, buckled and eroded; seas rose and fell. The rain tapered off, and the beetle rode these changes like a cork on the ocean.

Earthquakes, avalanches and floods were long suspected to be the secret of its mobility, and as Hawks’ diagrams are beginning to confirm, the evolution of Pleocoma mirrors the cataclysmic formation of California, mountain range by mountain range.

This little bug’s surprisingly eloquent perspective on the creation of this region -- both what is known and what is debated -- is perhaps the greatest reason for its charm.

“Rain beetles are one of the shining examples of how we’re not paying attention to the things underfoot,” said biologist and rain beetle expert Ian Swift. “They encompass poignant and powerful stories raging today not only all over the world but here in California.”

Pleocoma is only one small chapter in the broader narrative of the region. Redwood trees, kangaroo rats, slender salamanders and condors have equally important stories, as do the San Andreas Fault, the granite uplift of the Sierra, the rivers of the Central Valley. No one species, no one phenomenon can tell us all we want to know.

Only through the accretion of knowledge -- the collecting, the sequencing, the analyzing -- do we approach the possibility of understanding events that we could never imagine.

--

“They’re out!”

Waterworth shouts and starts running through the woods. Suddenly Hawks and Ernst are also chasing these amber dots through the forest, around trees and beneath low branches.

The sun is dimming in the west. The wind is blowing cold. Hawks had just set up his traps -- buckets inside of buckets with a lantern perched on top -- and he is smiling. This patch of woods is perfect.

With headlamps bouncing through the dusk, the entomologists follow one bug as it zigzags 3 feet to 6 inches off the ground. Pleocoma are no aerialists, but grace in flight hardly matters as this one hones in on a female’s pheromone blooming invisibly into the air.

Not unlike Lemon Pledge, someone says, if you happen to catch a whiff.

Circling in diminishing loops, this bug finally touches down and crawls into the dirt. Another male lands nearby. Then another.

Hawks plants the edge of his shovel into the ground and turns the soil. Amid the clods, two beetles are crawling on one another. It is a scene that is being enacted all over this mountainside. The scientists crouch down, just inches above the pair.

They see the lamellae, which picked up the scent, fanned out. They see the male’s extended aedeagus, his tarsi grappling with the female’s thorax and abdomen. Outside the confines of Earth, he struggles for purchase, then seems to succeed.

Within a week, he will be dead, his fat reserves depleted; the female will die a few months later, but not before she deposits her fertilized eggs deep underground. The grubs will hatch, start feeding on shrub and tree roots and wait about 10 years for the right snow melt to bring them to the surface.

The sky grows darker, and the flight of beetles slows. Soon the forest is quiet, lighted by only the visitors’ lamps and the beetle traps, casting a shadowy glow among the oaks and pinyons.

The stars have emerged. Orion looks down from afar, and in the late twilight glow, spring is in the air.

--

thomas.curwen@latimes.com

--

latimes.com/beetles

More beetles

Two photo galleries reveal the world according to beetles.