The Dark Side of Entomology

An Academy researcher crosses over to the dark side to study one of the most underappreciated insects in California.

They emerge from the ground only at night, and they eat the dead. Their humanlike heads have earned them nicknames such as "old bald-headed man" and "child of the Earth." And although encountering one of these creatures of the dark can send chills up your spine, the once-demonized Jerusalem cricket, according to Academy research associate David Weissman, may be one of the most important insects in California.

Once thought rare and insignificant, Jerusalem crickets, Weissman has discovered, are a vital part of many ecosystems. They give life to the night, forming the foundation of food chains across California. Bats, skunks, and foxes are among the many nocturnal animals that feast on the plump, 5- to 10-gram insects. While underground, where the crickets spend most of their lives, they gnaw at plant roots and dead animals, helping to aerate soils and recycle nutrients.

Jerusalem crickets can be found under rocks and in sandy soils throughout the western half of the United States, and from British Columbia to Panama. But they are the most diverse in California where, Weissman says, "they can literally be found by the hundreds." While Weissman has been chasing down and identifying Jerusalem crickets for the past 20 years, much about these ill-favored insects remains in the dark. For one, Weissman estimates he's collected up to 60 new species to science, about 40 of which are native to California.

Map by Colleen Sudukem

 

This as yet undescribed species of Jerusalem cricket found throughout Southern California is the second heaviest insect in California, with some adults exceeding 3 inches in lenth.
Photo: Dave Weissman

While Jerusalem crickets are widespread throughout California and the west, they usually only come to the surface when the weather is cold and wet. They are often found in landscapes under rocks such as the above and by looking under boards and other debris.
Photo: Dave Weissman

Curatorial assistant Vince Lee of Entomology sifting for Jerusalem crickets in sand-dunes in winter, in Kern County, California. Sifter is suspended under a camera tri-pod. Highest yields usually occur when the sand is very moist and hard to sift.
Photo: Dave Weissman