The Environmental Journal of Southern Appalachia
Thursday, 26 August 2021 15:40

(News alert: Katy did it!) Seventeen-year cicadas were just an opening act. Now the woods are rolling with the rhythm of our annual insects.

Written by

Bales Common true katydidA true katydid is shown here. It’s one of the main insects that provides a permanent soundtrack to your summer life in the Knoxville area.  Stephen Lyn Bales/Hellbender Press

What’s that buzz? We thought Brood X was over.

In case you haven’t noticed: It’s hot!

The “dog days of summer,” are so called because the season coincides with the period of time when the brightest star Sirius, aka the Dog Star, rises and sets with the Sun: early July through August into September.

The ancients believed that when Sirius and the Sun were in the sky together, the days were hotter. I think they got it right.

August has never been that thrilling to me, more of a month to endure. The birds have finished raising their families and are going through their late-season molt. Some of the migratory birds have already started to move south. But that doesn’t mean that our backyards are totally silent because late summer is cacophonous with insects.

During the day, the trees are filled with large, green cicadas that generally spend three years underground in their larval stage, but they are not all in sync like Brood X was, so each summer we have plenty that mature to collect en masse in our neighborhoods.

To attract females, the male cicadas do the chainsaw buzzing, but the songs are not made with vocal chords but rather special organs on the sides of their abdomens called “tymbals.” In effect, their sides vibrate loudly.

Locally in the Knoxville region we have five species of these annual cicadas. Early in the morning and into the afternoon, swamp cicadas (Neotibicen tibicen) are calling. They are also known as morning cicadas because they usually crank up by 10 a.m. with a long uninterrupted rattle that builds in intensity.

During the hot part of the day we hear Robinson’s cicada (Neotibicen robinsonianus). They are plodding and rhythmic: creeeeeak, creeeeeak, creeeeeak, creeeeeak.

And from afternoon to twilight the scissor-grinder cicada (Neotibicen pruinosus) takes over. It supposedly sounds like someone sharpening a pair of scissors on a grindstone, with hyper-rhythmic pulses that build in intensity. Their calls have also been compared to a circular saw cutting though a two by four: zeeeer, zeeeer, zeeeeeer.

The last two local annual cicadas species: Lyric (Neotibicen lyricen) and Linne’s (Neotibicen linnei) are very high-pitched. They sound similar to Swamp Cicadas but their buzzes are at 7 kHz, a range that many people cannot hear or barely hear.

Did someone say “katy-did-it”?

Scissor-grinder cicadas buzz until darkness falls when they are replaced by the nighttime orthopterans that are in the same order as grasshoppers, locusts and crickets. Like the others in that insect group, katydids (Pterophylla camellifolia) have long legs in the rear that enable them to jump quickly. They are camouflaged to look like green leaves and spend their entire lives in the canopy, rarely being seen on the ground unless they fall.

Their common name comes from the sound they seem to make in the dark: katy-did-it, katy-did-it, katy-did-it!

Being able to identify these various insect courtship sounds make the Dog Days of summer a little cooler. And you can impress your friends sitting on the back deck or whiling away a few days in the woods.

Stephen Lyn Bales is a natural historian, the author of three UT Press books: Natural HistoriesEphemeral by Nature, Ghost Birds. He’s also a monthly speaker (via Zoom) for the UT Arboretum Society. He can be reached via email to “stephenlynbales” at

Rate this item
(1 Vote)
Last modified on Tuesday, 21 February 2023 16:33