Voices in The July Night Belong To The Insects

On July 16, 2011, Docents Bob and Joyce Hartmann led a public dusk/night walk to listen to the “Voices of the Night”, braving the 90-100 degree temperatures that had been prevalent for several weeks. However, it was at least ten degrees cooler there in the woods than it was downtown.

We met at dusk at the cabin, where we heard several kinds of cicadas, a Barred Owl, a Yellow-billed Cuckoo, a Northern Cardinal, and people talking and playing music in nearby boats on the lake. As we walked, constantly droning daytime cicada songs gradually gave way to the night sounds of clicking katydids, along with a few crickets. At the first cedar bench circle, we again heard the Barred Owl, and a sudden loud barking warning sound from a Whitetail Deer whose territory we had invaded. The katydids presented their song overpowering concert in full “surround-sound” stereo. It was very relaxing to listen their rhythmical sounds.

Returning the same way we came, we found it quite enjoyable to spend a hot summer evening strolling in the woods along the lake, and recommend the cedar benches as an ideal place to witness a sunset over the lake. And we learned that at the Nature Center, definitely, the Voices of the Night in late July belong to Insects!

Speaking of Insects…
The cicada produces some of the loudest sounds in the insect world. The males “sing” during daylight hours with two ribbed membranes called “tymbals” that click when muscles rapidly contract and release; the two tymbals click alternately. Air sacs in the hollow abdomen amplify the sound, and vibration through the body is also amplified through tympani. Sounds of one insect can be louder than 100 decibels, so imagine the noise produced when a large group sings!

Both male and female katydids, on the other hand, sing at night, producing sound by rubbing their forewings together. There’s a file on one wing and a scraper on the other. The wing membranes and the position they’re held in amplify sounds. The males sing loudly and females chirp in response. They both hear with ears (tympani) on their front legs.