“What is that huge, weird bug in the road? And what is it doing?”
We were hiking along a dirt track in Sinks Canyon, Wyoming (a totally gorgeous place, by the way), when we came across a large insect I didn’t recognize. I should have. A bit of research revealed that it was a Mormon Cricket (Anabrus simplex), and not only are they common, but at times they’re so abundant that their voracious appetites consume the landscape!
They do look sort of “cricket-y,” but Mormon crickets are actually shieldbacked katydids, also known as long-horned grasshoppers (family Tettigoniidae, subfamily Decticinae). They are found all over western North America, preferring sagebrush/grass rangeland similar to the place we found this one.
While I have never seen one in my garden (thankfully!), they are a significant agricultural pest. In addition to their usual diet of sagebrush and saltbush, dandilions, milkvetches, and other forbs, they are particularly fond of cultivated crops such as wheat, barley, alfalfa, and garden vegetables. At times populations soar. According to the Wyoming Agricultural Experiment Station Bulletin 912, “… migrating bands of nymphs or adults may completely destroy fields of sugarbeets, small grains, and alfalfa. During the 1937 outbreak, crop damage in Montana amounted to $500,000 and in Wyoming to $383,000.” That was a lot of money in those days.
They’re called Mormon crickets because these are the insects that, in 1848, threatened to decimate the first crops of the early Mormon settlers in Utah. The crops were saved by large flocks of California Gulls who flew in and devoured all the crickets. There is even a statue in Temple Square, Salt Lake City in honor of the gulls.
What caught my attention, along with the sheer size of the insect we happened upon, was that it had inserted a part of its body into the ground. Turns out our cricket was a female, and she was laying eggs. I was fascinated by how these insects reproduce. The male transfers to the female a large spermatophore that not only contains his sperm, but also a great deal of protein—up to a quarter of his body weight. After the sperm have moved into the female’s body, she eats the spermatophore. The protein boost strengthens her for the business of egg laying. This significant reproductive contribution by the male is rare among insects.
The female is easily identified by her huge ovipositor. She inserts this organ into the ground over and over, laying one egg each time. Females lay an average of 86 eggs each. Once the crickets have reproduced, they die.
The eggs incubate in the ground all fall and winter, hatching when temperatures begin to warm in the spring. They young insects pass through a series of instar stages before reaching adulthood during the summer. Unlike caterpillars and butterflies, the immature instars resemble small adults.
While Mormon crickets cannot fly, they are highly mobile. An adult can cover up to 50 miles during its lifetime. I’m just glad they haven’t showed up here among my veggies!