SUPERIOR TWP – Brood X cicadas have begun to emerge in Michigan — and Ann Arbor is at the epicenter.
Hundreds of the eerie red-eyed insects were visible just east of town at Kosch-Headwaters Preserve Monday morning, climbing the small saplings and teasle reeds that line the trails to molt their exoskeletons before emerging as adult insects.
In the coming weeks, the adult male cicadas will join in a chorus make their distinctive siren-like call, mating with females who lay their eggs in twigs and branches before dying within a period of about two months. Once the eggs hatch, the nymph cicadas will drop to the forest floor below and burrow underground, not to emerge for another 17 years.
Tom O’Dell, Matthaei-Nichols natural areas specialist, says that the insects haven’t yet been spotted at the nearby Matthaei Botanical Gardens, but he’s expecting to see them soon and keeping an eye on sites where they previously emerged in 2004. O’Dell says that while the insects don’t emerge all at once, he expects that by mid-June the insects and the loud, droning noise they produce will be at their peak.
The insects don’t pose any threat to humans or animals, but might do damage to smaller trees less than three years old, he said.
“Before, people would find them disgusting, as many still do, or people couldn’t care less,” O’Dell said. “So suddenly, there’s a great interest in this big event and people are either looking forward to it or they’re scared.”
On social media, residents shared photos of cicada sightings in the Burns Park neighborhood as well as at nearby Cherry Hill Preserve. In April, the city warned that the insects might swarm the city, appearing in the thousands.
‘They’re going to be everywhere,’ said Tiffany Giacobazzi, the city’s urban forestry and natural resources planner. “We could see several hundred thousand to a million insects per acre.”
While the insects may benefit larger trees, the incisions made in limbs and twigs during their egg-laying process puts younger trees and shrubs at risk. In response, the city suspended its spring tree planting and created a webpage to advise residents on how best to protect their own trees and plants.
The city recommends residents place a layer of mesh or netting over exposed saplings with openings no larger than one quarter inch, and suggests securing the covering around each tree’s trunk to prevent insects from crawling up from the ground.
The city’s website also cautions residents against using insecticides, which are harmful to beneficial insects and ineffective against cicadas in large numbers.
Brood X – the most widespread of the periodical burrowing cicadas – last emerged in 2004. Other broods of burrowing cicadas have appeared between then and now, but their range is usually limited to the East Coast and other Midwest states like Ohio, Indiana and Illinois, according to Howard Russell, an insect/arthropod diagnostician at Michigan State University.
“This only happens once every 17 years and it’s a force of nature,” Giacobazzi said. “I think it’s amazing.”
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