The spring started with alarming news reports about the coming 17-year-cicada invasion. We were told to expect them to blanket the sky and ground. So far, that has not happened in much of the Metro area, with the exception of Virginia. According to an expert in the Smithsonian’s Entomology department, if you haven’t seen a cicada invasion yet then you probably won’t. They have come and are almost gone.
The cicadas we were expecting, a species that last visited in 1996, are called Brood II. They’ve been buried deep in the ground for the past 17 years, maturing, and emerged as soon as the soil reached a consistent temperature of 64 degrees. “Once they emerge their life span is maybe a few weeks,” says Gary Hevel, who calls himself a “generalist” but who has specialized in studying so many species of insects he became the subject of a documentary called Bug-Hunter. He says he’s been studying cicadas for years and calls them “undeniably fascinating.”
So what happened? Climate played a role in the smaller turnout this year, he says, as did urban development—anything that disturbs the trees, such as the building of shopping malls, housing developments, and concrete roads. This spring the temperatures have been flukey, swinging from very warm to fairly chilly. “The cool weather plays a role with the cicadas and other insects,” he says. “There’s not a large population this spring.”
Where are they, if anywhere? “For the most part the Brood II are not appearing that much in the District and Maryland,” Hevel says. “They are prominent in Northern Virginia. They sort of skipped over and hit Baltimore and the north. Some neighborhoods can have them heavily, whereas a few blocks away they are not present. But they are pretty much out.”
The cycle of the cicada life is basically this, according to Hevel: “They mate and lay eggs. A female stabs a tree branch or twig with an ovipositor, laying her eggs there. Five weeks later the hatchlings emerge, break out of their branches or twigs, dive-bomb the ground, and dig into the soil to look for a root to suck juice from.” He says they will remain at a depth of several feet for another 17 years.
Those neighborhoods that didn’t see Brood II cicadas could still see the more ordinary “common local cicadas” that emerge in late summer, with the males singing from the treetops.
Should we be concerned? “Cicadas are harmless,” says Hevel. “People will argue with that if they are riding a motorcycle and one hits them in the face. But they don’t bite, they don’t sting, and everything eats them, including dogs, snakes, frogs, birds, and even humans, on occasion.”