At any given time during the month of May, it’s not unusual to hear ambient sounds from bird songs, rustling winds, or thunder and showers.
It won’t be long, though, until another deafening sound is heard — the harsh buzzing choruses from 17-year-old cicadas when they emerge this spring.
This particular batch of cicadas — Brood VIII — have been underground for nearly two decades, awaiting their time in the sun once again.
Absent since 2002, this brood will likely only impact the western part of the state, according to a National Public Radio (NPR) report.
As for when they’ll arrive, there’s no easy answer for that. In some areas of the state, cicadas have already begun to creep from their underground dwellings. It’s far delayed in other counties, though.
“We have the issue today of global warming and climate change, which makes it much less predictable,” said Robert Davidson with the Carnegie Museum of Natural History in the NPR report.
“In the past, you could pretty much count on mid-May and they’re usually out for about six weeks. The adult form lives for about a month, but they don’t all come out at once. They come out over a couple-week period.”
The National Climate Data Center did note, however, that it depends on soil temperature.
“It is believed that the particular night of the periodical cicadas’ emergence depends on soil temperature. Cicada juveniles, or nymphos, emerge when the soil temperature at 8 inches in depth exceeds approximately 64 degrees,” their officials said.
When they do emerge, it’ll be hard to miss them. Though they’ll crawl from the ground looking a bit dull, they’ll soon shed their wrinkled outer layer. Adult cicadas have bulging red eyes and orange-tipped wings — a striking site against a dark black body.
It’s at that point that the males will take to “trees or bushes and bellow out their calls,” Davidson said in the report.
“The females select their mates and alter cut a small scar into tree branches, where they lay their eggs before they die,” the NPR report said. Fast forward 6-10 weeks, the eggs hatch to reveal tiny nymphs that once again creep down to the ground below and await their next appearance, which for Brood VIII will be 2036.
Cicadas are relatively harmless. They’re don’t bite or sting. But that doesn’t mean they don’t have negative impacts on plant life around them.
“The periodical cicadas were considered a bit of a pest, as they laid their eggs on the twigs of trees, causing damage to newly planted, young trees as it occurred in such large numbers,” said Mark Tebbitt, a professor with the department of biological environmental sciences with California University of Pennsylvania in a previous interview.
“In both cases, the adults are short lived only surviving long enough — a few days — to reproduce the next generation,” he continued, also referring to the green and black cicadas that emerged two years ago.
Those cicadas, also known as the “dog-day cicadas,” generally appear every two to five years. Staggering those broods with adults maturing at different times, you’re likely to see those smaller, greenish cicadas at some point every year.
But the larger, reddish-orange cicadas of Brood VIII will be with us for about two months, before creeping back to the ground. It’ll be a larger brood, too, with the NPR report noting that up to 1.5 million of the insects have been documented in a single acre.