While butterflies look for mates quietly, using visual and chemical signals to find them, some insects send out loud calls, often in chorus. The most notable about these insect singers are cicadas and katydids. Together, they fill Virginia summer days and nights with pulsating, percussive songs that, to me, is comforting white noise. When the bugs are singing, all seems well.
With all the wet weather this year, I didn’t hear either cicadas or katydids in full chorus until a couple of weeks ago. Now their sounds and the those of other singing bugs come during dry spells and go with the inevitable return of rain. Flying insects, such as cicadas and katydids, are hindered from flying to potential mates when it rains, but perhaps a more-serious effect rain has on these singers is the noise it causes. Why waste energy serenading prospective mates if they can’t hear you over the rainstorms?
Katydids mostly sing at night, but cicadas are daytime crooners. With no periodical cicada broods scheduled to emerge for a few years, the annual cicadas are the ones now dominating insect sounds during the day. Their sounds can vary in volume, pitch and pattern. Both genders call, but it’s the males’ loud humming, produced through special membranous, sound-producing organs (tymbals) in their abdomens that aggregates cicadas into groups for breeding.
Female cicadas have excellent hearing and can easily determine a male’s location and calling intensity. They respond by flicking their wings, which makes a clicking sound that draws the males to them. Having a chance to breed only every 13–17 years, periodical cicadas are so eager to mate that researchers have drawn them in by making clicking sounds at the right intervals.
I borrowed the title of this column from David Rothberg’s fascinating 2013 book (and associated CD), “Bug Music,” on the sounds insects make and how they relate to human music. He uses the word “bug” as a lot of us invertebrate lovers do — as an affectionate term for insects in general, not specifically insects in the True Bug (Heteroptera) suborder, which does include cicadas. Rothberg digs deep into the weeds, literally and figuratively, in exploring the science of insect sounds, as summarized in the subtitle of the book: “How insects gave us rhythm and noise.”
While I am generally a lover of insect noise, I acknowledge that some of it can be grating. Take, for example, the loud song of the aptly named scissor-grinder cicada (Neotibicen pruinosus), which usually choruses in the copse next to my deck. And it’s hard to forget the volume as well as the spaceship-like tones of an emerging brood of periodical cicadas, which we last heard in our area the year Rothberg’s book came out. That was less a case of the individuals cicadas’ song as the sheer numbers singing together.
Rothberg opines that musicality of the cicada “may be in the precision of its noise” and equates it to techno electronic music popular in today’s dance clubs. He describes how Granulator, software developed by a German electronic musician to add texture to techno music, can also construct bug-like sounds. Starting with “microscopic, tiny instances of tone or noise,” Rothberg writes, the software helps to recombine them in “layers of complexity and irregularity” and loop the results to make sounds like those of insects — “literally produces a swarm of sound.” Inside Granulator, “we are all arthropods” (invertebrates), he adds, and “a tiny blip of our sounds can be made infinitely large.”
This year, I’ve heard only one or two scissor-grinder cicadas in my copse, although plenty have been chorusing elsewhere in Rappahannock County. In their absence, I’ve been able to hear more clearly the subtler songs of other cicadas that chorus in the forests around my house. To identify the singers, I visited one of my favorite websites for insect sounds, “Songs of Insects,” also available as a book with an accompanying CD of the songs. Both are the products of Lang Elliott and Wil Hershberger. For each species, the book also has range maps, photos and a sonogram of its song. (This book and Rothberg’s are available in the Conservation Collection of the Rappahannock County Public Library.)
In checking cicada songs on the website, I decided the main singer around my house this year is Linne’s cicada (N. linnei), another species in the Neotibicen genus. Its high-pitched, rapidly pulsating song starts softly but increases in volume, becoming, as Elliott and Hershberger describe it, “a steady pulsating rattle sounding like a saltshaker” before ending abruptly.
In between the Linne’s chorusing, I can hear the even-subtler lyric cicada (N. lyricen), with its buzzy, rattling trill. Unlike other cicadas within this species’ range, its song does not pulsate. It starts softly, then increases in volume, which sometimes fluctuates, before finally ending.
By their songs, I ruled out the four other annual species that range into my area, on the border of Virginia’s Piedmont and Blue Ridge regions: northern dusk-singing cicada (Megatibicen auletes), Robinson’s cicada (N. robinsoniana), Say’s cicada (Okanagana rimosa rimosa) and swamp cicada (N. tibicen tibicen). Last summer, I had recorded and photographed the swamp cicada in a wetland at Leopold’s Preserve, near Haymarket.
While sorting out cicada songs is relatively easy because of the small number of cicada species here, katydids present a much bigger challenge, as I’ll explore in my next column. Until then, consider Rothberg’s summation of his book’s theme, expressed in the prologue:
“The stridulation of crickets, the tymbaling of cicadas, the tap-tap-tap-ing of treehoppers, the thrum of bees. As long as we don’t feel threatened by them, most people like these sounds. The rhythms of insects bind us to the landscape, the warm weft of early autumn, a smile at the seasons’ march. One small sense that ties us to the eternal, for like all animals sounds, they have been around for millions of years longer than anything human. And the most important thing about them is that they may be the very source of our interest in rhythm, the beat, the regular thrum. And noise. Yes noise. Our love of noise.”