By FRED SEITZ — It’s hard to miss the daytime and evening melodies of our local insects, including an assortment of grasshoppers, crickets, katydids and cicadas. These orthopterans (the first three) and hemipterans (the last one) grab our attention from tree limbs, fields and sometimes our houses. All of their songs are quite different, but they often intermix and become a little difficult to differentiate, especially when the volume of their choruses can easily approach, and sometimes exceed, 100 decibels (equivalent to a motorcycle or power lawn mower).
Most of these songs are produced by stridulation, which involves rubbing wings together or wings against legs. Grasshoppers, who are usually in fields or other grassy areas, are the quietest of the lot, opting for occasionally rubbing forewings again rear legs. They can also make a popping sound when they fly. Grasshoppers limit their music to the daytime.
Crickets are familiar to all and frequently live in our basements, sheds and other dark locations. The ones who serenade us at night, however, are often tree or shrub dwellers. Rubbing their wings together produces the often rasping or chirping sounds we hear. One of my personal favorites (and easier to identify) is the jumping bush cricket whose single loud “peep!” is quite distinctive in the evening.
Katydids are fairly large and are usually green in this area. They can easily disguise themselves on the leaves they perch on, which are often near treetops. There are numerous types of katydids in Maryland, each having a distinctive song. These songs include a variety of “shush” sounds, including the famous “katy-did” or “katy-didn’t.”
The last of our summer songsters is the most famous and loudest, the cicada. Their familiarity stems from their loud songs and their 13- and 17-year lifecycles. (Those deafening our ears now are of neither brood, though, but the annually emerging population.) Unlike the previous performers who rub wings together or legs against wings, cicadas have membranes called tymbals on the sides of their abdomens. Moving these membranes creates the loud sounds familiar to all.
While the sounds of all our singers are distinctively different, their inspirations for singing are essentially the same: They sing to attract mates and to defend territory. Another commonality among our four singers is their attentiveness to temperature; their songs and activity often diminish on cooler evenings.
In late August, you can join the Cricket Crawl, a popular citizen science activity. All you need to do is venture into your backyard — or step out on your porch or balcony — and listen. The downloadable sounds of various target species are on the Cricket Crawl website at http://www.discoverlife.org/cricket/DC/.
