By Martha Siegel
It was an awfully loud summer, but lately, things have gotten a lot quieter as the chilly fall air has settled in. A couple of days ago I heard one feeble chirp in my field, and that might be the last Orthopteran I’ll hear this year.
“Ortho-what?” you might be thinking. Dusting off my taxonomy levels from tenth grade Biology, I recall kingdom, phylum, class, order, family, genus, species, with each level descending into more specificity. Orthoptera is the name of the order of insects that includes crickets, grasshoppers, and katydids (also locusts, which we don’t see in our area, but NOT cicadas, which we do see). It can get a little confusing, but I hope to shed some light on these insects and pass on a few interesting tidbits.
First of all, why did I get curious about Orthopterans? In a word, SLEEP. As in, all the sleep I did not get while listening to, you guessed it, Orthopterans. It was a warm summer, and my windows were wide open most nights. I began to wonder about the cacophony of rasping, buzzing, trilling, and chirping, and I felt the need to tease out the sounds. I am an avid fan of the natural soundscape of Maine, so I am on a journey to know more about what I am hearing.
According to the Maine Biota Project, an astonishing 89 species in this order have been identified in Maine. The word Orthoptera means “straight wings,” which members of this order have. They also have mouth parts for chewing (mostly plants), powerful hind legs for jumping, and the ability to make sound by rubbing various body parts together. This type of sound is called stridulation (short “I” sound as in kid). To simplify, crickets and katydids rub wing parts together to make sound, whereas grasshoppers rub wings against hind legs to create most of their sounds. You might also have heard the snapping sounds of grasshopper wings in flight. All of this noise is a way to communicate. Such insects receive these sounds in various ways throughout their bodies, rather than with two ears like we do.
In order to untangle who we are hearing at any given time, first we need to filter out those amphibian sounds of early (and occasionally late) summer, such as toads, peepers, and other tree frogs. Then there are the cicadas, who emit a long, loud buzz.
That leaves the Orthopterans.
Grasshoppers are mostly daytime noisemakers, who make clicking or rattling sounds. Katydids, which we hear at night, make rhythmic rasping sounds, sometimes with three syllables; thus “ka-ty-did.” Most of the rest are crickets, some of which sing both day and night. Field crickets are black, and I associate them with trilling chirps from the ground level. I was surprised to learn that the very loudest crickets of the night, which produce an outsized chorus of rhythmic trilling, are tree crickets. These are small and greenish, quite different from the familiar black field crickets. Sometimes multiple crickets sing in a synchronized way, which is easy on the ears. But when a couple of voluminous tree crickets get out of sync, that’s when I lie awake thinking, “Come on guys. Get it together!” (Here is a 15-minute video from Cornell on stridulation.)
In any case, what is happening to the Orthopterans right now as I write? Mature adults generally die off before the winter cold. However, these species survive underground as eggs or nymphs and emerge into their next life stages the following spring. Meanwhile, it’s time to shift our attention to wintery pursuits. But I look forward to next spring, when I will be ready to absorb and learn a whole new batch of sounds from the creatures of Maine.
Sources:
https://www.youtube.com/watch?v=FEHbY-ZkzVo (an outreach video from Cornell University about insect sounds)
Photo Credit: Martha Siegel
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