Associated Press Writer
CINCINNATI—An entomologist who has been studying cicadas for decades says something appears to be going wacky with the obnoxiously loud insects' body rhythms — and he believes it's related to climate change.
Cicadas seem to be forgetting how long they're supposed to sleep and when they're supposed to emerge from the ground, he said. It's getting harder and harder to tell the broods apart.
Cicadas are coming out of the ground on the Eastern seaboard, primarily in North Carolina, four years ahead of schedule, Gene Kritsky, a biology professor at the College of Mount St. Joseph, said Thursday.
They're from Brood II and were not supposed to show up until 2013. But within two weeks, they could range up into Connecticut, Kritsky said.
No brood was expected anywhere in the U.S. this year, so Kritsky expected to be free to work on another book on honeybees and to install an exhibit, Darwin's rEvolution, that opens in a week at the Cincinnati Museum Center.
Instead, he's in full cicada mode. He's been studying them for 35 years.
Cicadas spend most of their lives underground, living by sucking fluids from plant roots. They emerge after the soil temperature exceeds 64 degrees, usually late May, then mate and die in four to six weeks.
The system of naming broods was started in 1893 by an entomologist working for the Department of Agriculture. There are 12 broods of 17-year cicadas and three broods of the 13-year variety, in addition to annual cicadas.
Last years' Brood XIV, which ranged from the Ohio Valley to Massachusetts, was first recorded in 1770 and first observed in Ohio in 1804.
Kritsky said that cicadas count the passage of years by the pattern of fluid flow in tree roots — and that a mild December-January followed by a hard freeze and then another period of warmth affects that flow.
"It's definitely because of warmer temperatures — not because it's warmer for the cicadas underground, but because it's warmer for the trees," Kritsky said.
"Our working hypothesis is that the way juvenile cicada nymphs keep time is by the way fluid flows in tree roots. If the timekeeping gets messed up in the first four years, they will come out four years early."
This is the fifth brood of cicadas since 1995 that he's documented emerging four years early. In 2000, he marked trees where Brood X cicadas laid eggs; if those cicadas emerge in 2017, Kritsky believes it will be a whole new brood.
"It's like evolution happening before our eyes," he said.
Kritsky, who has published five books and more than 100 scientific papers, expects his most recent findings to be published this month in Proceedings of the Indiana Academy of Science.
Not all Brood II cicadas will emerge this year, perhaps 5 to 10 percent of them, Kritsky said, instead of the billion that can be in a brood.
When cicadas emerge a billion strong, they can create a deafening racket. They do not sting or bite humans but can harm young trees when females lay eggs in new growth.
Their carcasses litter the ground as they die, and some pets get sick by eating too many.
Some people even eat cicadas, which Kritsky says taste like cold, canned asparagus.
On the Net: