You've Heard a Bird Sing, But Have You Heard a Jerusalem Cricket's Drum?

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You’ve probably heard a bird singing to find a mate, or even a frog. But have you ever heard a Jerusalem cricket’s drum?

Side view of a large, solidly build cricket-like insect

Jerusalem cricket -- Ammopelmatus n. sp. "Santa Monica"

(Credit: David Weissman, California Academy of Sciences. Courtesy: David Weissman)

Jerusalem crickets are not from Jerusalem, nor are they true crickets. These big insects, sometimes called potato bugs, are native to the Western United States and Mexico, and are often spotted in California at night.

When it comes to finding a mate, Jerusalem crickets “drum” by striking the ground repeatedly with their abdomens. Both males and females drum, calling and responding in a “duet” until they locate one another to mate. Drumming patterns are unique to many species of Jerusalem cricket. Calling drums for different species vary in many ways, like drumming rate, length of drum, grouping of drums, or intervals between bursts.

Though you can hear Jerusalem cricket drums in the wild, researchers bring them into the lab to record and analyze their distinctive calls. They place the insects in a dark room under a microphone and leave them for a few hours. Some species can be stimulated to “duet” when a researcher taps a finger to mimic the drumming of the opposite sex. The calls can be analyzed with the same kinds of audio software people use to record or edit music. 

At right, click play to listen to a recording of a Jerusalem cricket from Marin County, California.

The mating drum of a Jerusalem cricket from Marin County, CA.

David Weissman, California Academy of Science

(Used with permission.)

USGS geneticist Amy Vandergast has studied the Jerusalem crickets for many years in collaboration with the California Academy of Sciences’ Jerusalem cricket expert David Weissman, contributing genetic data to studies of calling drum and morphological differences. Together, these patterns help researchers understand species diversity in this group, from how these animals first evolved and diversified to how their species and populations are influenced by habitat loss and fragmentation today.

But when many species of Jerusalem cricket were first defined and described, more than a century ago, there was no information on their drumming patterns. Today, researchers have detailed information on drums, as well as DNA, and are using these data to redefine the old taxonomy to fit evolutionary relationships. In a recent publication on Jerusalem crickets, Vandergast and colleagues suggested that drum information was essential for defining species, even more important than DNA, and that every new Jerusalem cricket description should have this information.

Close up on the face of a Jerusalem cricket, staring right at the viewer

Jerusalem cricket, from Montezuma Castle National Monument

Credit: National Park Service (Public domain.)

The finer distinctions of Jerusalem cricket taxonomy may seem like an obscure thing for USGS scientists to study. But the answers to big questions about how species and ecosystems respond to disturbances like habitat loss and fragmentation depend on a solid foundation of what species are and how they got that way.

Click here to learn more about how USGS uses genetics and other information on species diversity to answer conservation questions.