Entomologists are on the trail of the elusive rain beetle, whose evolution seems to mirror the cataclysmic formation of California

The windshield of Dave Hawks’ SUV is splattered yellow from bugs, but Hawks doesn’t mind. He’s speeding north on U.S. Highway 395 and running the wipers would only make matters worse. Spend time in an entomologist’s company and you make peace with insect juice on the windshield.

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.

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