Here in Penn’s Woods, residents are treated to a nighttime serenade of buzzing, chirping and other sounds from nature as summer slips away.
Some would call it a symphony, others a cacophony — depending whether it lulls them to sleep or keeps them up — but what is it that’s making all the racket?
According to Entomologist Greg Hoover of the Penn State Cooperative Extension, many people incorrectly attribute this nightly noise to cicadas.
While a few species of dog-day cicadas are out right now, Hoover said cicadas only generate noise during the daylight hours.
“What people are hearing at night are katydids or tree crickets,” he explained. “Cicadas are active during the heat of the day, and as it gets cooler, their numbers are diminishing.”
Hoover said dog-day cicadas — named for the dog days of summer when they emerge — became active in late-July and peaked in early August. They’ve been declining in number over the past few weeks as they mate, lay their eggs and get plucked off as a meal by other animals, he said.
“I heard some over the weekend, but not near the number of individuals there were just a few weeks ago,” Hoover commented.
The recognizable sound of the cicada is actually the adult males flexing their tymbals — drumlike organs found in their stomachs, according to www.cicadamania.com. That’s a mating call to female cicadas, which don’t make the monotonous, buzzing noise.
While dog-day cicadas are recognized for their loud, shrill calls, Hoover said folks can identify tree crickets at night as a higher-pitched sound in comparison to the droning noise of the katydids’ repetitive clicks.
Katydids, which resemble a combination between a leaf and a grasshopper with wings, have been apparent for several weeks and are starting to peak, according to Hoover.
The dog-day cicadas look very different, having rounder bodies and big translucent wings lined with conspicuous lime green veins. He said there are many different species of dog-day cicadas, and they only take two to five years to reach maturity.
In some cases, they can be as much as two times the size of periodical cicadas, which have orange wing veins and emerge in early May every 13 or 17 years in various broods, according to Hoover.
“There are actually three species of periodical cicadas that will emerge during certain years in Pennsylvania; but with the dog day cicadas, there are several more species that would be apparent,” he said.
Both kinds of cicadas develop as nymphs, feeding on the contents of xylem cells in the roots of trees during their years underground before crawling out of the soil to breed, Hoover explained.
“I’m sure many noticed the nymphal exoskeletons apparent with both of these insects,” he said. “Children may be particularly fascinated to find them left behind on trunks of trees or fence posts. They’re usually intrigued, wondering why it isn’t moving, providing a great chance for parents to teach about the lifecycle of this group of insects.”
Their lifecycle, after shedding their nymphal exoskeletons, usually ends in the bellies of other forms of wildlife like turkeys, skunks and turtles, who get to enjoy a short-lived feast of the plentiful cicadas to help fatten up for the colder months, according to Hoover.
The next impressive 17-year cicada emergence in Pennsylvania will occur in the western part o the state as Brood VIII emerges in 2019.
As an entomologist, Hoover, of course, looks forward to the emergence of cicadas and other insects — but beyond his professional curiosity, he said he simply enjoys listening to their various calls that give an audible assurance of the life of the forest outside his bedroom window.
“We have great late-summer and early-fall noises in our Pennsylvania forests,” Hoover said. “These sounds are like rain on a tin roof for me. People in suburban areas aren’t going to hear these soothing sounds of nature — we’re lucky.”
