Studying beetles and the secrets of life

But Hawks,49,a research associate from the University of California,Riverside,isn’t just an entomologist. He’s a coleopterist,devoted to the study of beetles. Catch him in his native element—the foothills and mountains of California—and you’ll find him chasing a local variety of these bugs,often in the predawn and cold rain. Only under these conditions is he able to find the elusive rain beetle,an insect whose mysterious habits might explain how California formed and became home to such a diversity of flora and fauna.

The rain beetle is a species that emerges from nowhere to mate in the early morning or late twilight hours—and only during the winter rains. No one can say why rain beetles prefer to mate under such specialised conditions. The creature spends most of its life an underground grub that works the folds of earth,nibbling roots,waiting about 10 years for the rain,then mating and dying.

Perhaps equally odd is the fact that this seldom-seen bug has been studied as thoroughly as it has. It all began in 1856. Gold miners in California excavated a beetle stranger than any they had seen,and rather than stepping on it and moving on,they saved it. One day,John L. LeConte got his hands on it and delivered a paper to the Academy of Natural Sciences in Philadelphia.

Hawks,a molecular biologist,spends his time extracting DNA from insects. His funded research is in the realm of parasitic wasps and agricultural pests. Pleocoma,however,is a labour 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 colour. 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.

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 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.

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

Suddenly Hawks and his crew are chasing 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. 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 homes in on a female’s pheromone blooming invisibly into the air. 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. Within a week,the beetle will be dead,his fat reserves depleted; the female will die a few months later,after she deposits her fertilised eggs underground. The grubs will hatch,feed on shrub and tree roots and wait a decade for the right snow melt to bring them to the surface.