Welcome to the second Insect Insights! This post is about a creature nearly everyone has heard, but most people likely haven’t seen.
Tree crickets don’t always live in trees, and probably don’t fit your mental image of a cricket. They’re in the same family as grasshoppers (Orthoptera) and in the Oecanthus genus, pronounced “ee CAN thus.” One species of these delicate insects with absurdly long antennae, the prairie tree cricket, lives in the Mt. Pisgah meadows, and is the source of the trilling daytime song you may hear there. I’ve spent some time in the south meadows recently and photographed a few tree crickets. So far I’ve only seen females, who have smaller wings, hugged against their bodies, such as the light green one pictured above.
The males are the ones who make the mating call, and they do it by raising their more rounded wings vertically on their backs and rubbing them together. Most articles refer to the male wings as “paddle-shaped.” You can understand why when you see the veins that crisscross the wings — they look like strings on a tennis racket. The image at the end of this article is not from Mount Pisgah, but it is one I took in Eugene, included here so you can see what a male looks like.
According to an article by B.B. Fulton from 1926, there are three species of tree cricket in the Willamette Valley, plus the snowy tree cricket has two morphs. Snowy tree crickets, Oecanthus fultoni, are the “thermometer” crickets. They’re the ones that chirp at night, and you can figure out the temperature by timing their call. Dolbear’s Law from 1897 is fairly reliable: Count the chirps in 14 seconds and add 40 to get the approximate temperature in Fahrenheit. Snowy tree crickets are light green to yellow and, like all tree crickets, the distinguishing mark between species is cleverly hidden on the underside of the first couple of segments of their antennae. It’s a tough angle to photograph, but I’m fairly certain the male cricket pictured on the thistle is a snowy.
I believe the brown cricket, from a more forested area of Mount Pisgah, is Oecanthus Californicus, the third local species. This one is immature—you can see that its wings aren’t fully developed. Adult tree crickets live into late fall, when the temperatures get too cold for them. So there are plenty more chances to listen for, and perhaps see them, this year. Let us know if you spot a male!
Stay curious,
Karen Richards
Sources:
B.B. Fulton, The Tree Crickets of Oregon, 1926. Accessed online 8/24/20.
The best place for tree cricket identification is Nancy Collins’s site.