Cicada insects may emerge by the thousands

Wednesday, May 20, 2015

Singing males expected to raise raspy racket

Farmers might find themselves serenaded this summer with cicadas, winged insects that emerge as broods every 13 or 17 years.

The Missouri Department of Conservation (MDC) said a certain brood of cicadas will literally be abuzz in early summer.

For 17 years, a particular brood of cicada nymphs have been tunneling through the soil, sucking sap from roots, and growing from tiny specks into bumblebee-sized nymphs. They are expected to emerge by the thousands this spring and early summer in western Missouri and transform into winged adult insects, with male cicadas raising a raspy racket as they serenade females.

"It sounds like most of the cicadas are going to be to our west and north of us, like the Oklahoma-Missouri line and north Missouri-Kansas line" said Mike Petersen, private land conservationist for the MDC in Cassville. "[But that's] not to say we might have isolated density in our area.

Petersen has been working in the Cassville area for 15 years.

"Just two years shy of the last 17-year emergence," he said.

Petersen said people who were here 17 years ago might remember when the insects last emerged. He said the insects do not sting or bite, so there's nothing to worry about there. But, they just feel creepy crawly, he said.

There are two types of cicadas, periodical and annual.

The periodic are aptly named because they emerge as broods in 13 or 17 year cycles, depending on the brood. Mass emergences of the 17-year brood can range over several states that extend from Iowa to Texas, western Missouri and eastern Kansas. The 13-year variety occurs in southeast Missouri and portions of other states. But, the two broods are not expected to overlap. They generally start emerging in May and remain above ground through most of June.

In 1998, when the parents of the 17-year brood were mating, an adjacent 13-year brood also emerged. But that overlap only occurs once every 221 years, Lawrence said.

Petersen said it usually takes a few days of around 80 degrees fahrenheit temperatures before the bugs emerge from the ground.

"The soil temperature has to be 64 degrees and that kicks them into gear and brings them out," he said. "It's temperature related so hard to put a due date. Sunny locations are going to warm up more than shady ones. Basically, they come out, reproduce, then they die."

With the large number of cicadas emerging at one time, swamps birds and other cicada predators will have more insect food than they can eat, described as an evolutionary adaption by the cicadas, allowing the species to survive by overwhelming predators with sheer numbers and to produce another generation that will live n the ground for the next 13 or 17 years, Lawrence said. Wild turkeys will eat nymphs, and so will fish, where cicadas drop into the water. As fish go on feeding binges, anything resembling a cicada can prompt a bite, and anglers can use the insects for bait.

How long will the racket last? A month or a month and a half, Peterson said.

Annual cicadas, or dog-day cicadas, emerge from the ground every year and make their droning noise during late summer. The main differences in appearance between the two varieties are body colors and time of emergence. Annual cicadas have greenish bodies, dark eyes and are about two inches long. Periodical cicadas have striking red eyes, blackish bodies and are slightly smaller. Both types include various species.

"The 17-year cicadas have the red eyes," said Petersen.

According to Rob Lawrence, forest entomologist for the MDC, the cicadas will begin emerging from the soil in early to mid-May, depending on how quickly weather conditions warm soil temperature. Current conditions could prompt the emergence to begin May 10 to May 12 in the Kansas City and St. Joseph areas, Lawrence said, though warm temperatures could slow emergence. Periodical cicadas pose no threat to people and minimal threats to trees. But early summer will be abuzz with sound where 17-year cicadas emerge.

"In some places they make a pretty loud noise," Lawrence said.

One year on a fishing trip, Petersen remembers seeing and hearing the insects.

"The tree limbs were drooping with them," he said. "It was a hum that drove you nuts when you were out. It's mother nature at its best. It's a neat thing, something you don't see every day."

As they emerge, here are some things homeowners can be looking for.

Cicada nymphs will open small holes in the soil. Some may build three- to five-inch tall mud chimneys above their holes. Wingless nymphs will climb up on trees and other objects, shed their exoskeletons, and become adults with wings. That leaves brownish paper shells that resemble shed skins attached to trees, porches and posts.

Adults will climb or fly into trees. Males will join together to form choruses to attract females. Male cicadas rapidly flex two drum-like structures in their abdomens just behind their last pair of legs called tymbals, making a loud click each time, which creates a high-pitched droning sound. The clicks come so fast it produces a raspy-sounding hum. The periodical variety are only about half the size of an adult pinkie finger, but these musical insects can drown out a chainsaw. The sound is similar to a plastic soft drink bottle popping back into shape after being compressed. The males sing during the day, and the loudest male can best be heard during the hottest part of the day.

Annual cicadas appear each year and by comparison, their drone ebbs and flows in the tree tops. But, annual cicadas appear later in the summer than the periodical variety, Lawrence said. Periodical cicadas will be prevalent in late May and June, annual cicadas appear in July and August.

Periodical cicadas will not appear in the same place every year, Lawrence said. A field or yard that did not have trees 17 years ago, for instance, would not have provided a place for females to lay eggs and for the nymphs to hatch and drop to the soil. Also, soil condition changes, severe drought or construction disturbances can reduce the number of nymphs.

After mating, females cut slits in pencil-sized tree twigs and deposit their eggs there. Eggs hatch in six to 10 weeks, and the tiny cicada offspring return to the safety of underground burrows, where they feed on roots until they mature and stage the next mass emergence. Given these facts, cicadas can affect trees, causing stress on limbs. Large, mature trees are generally not greatly affected. Homeowners may notice some browned and broken branch tips, which is called flagging. Young trees can be harmed, and fruit trees can be stressed, because they have small branches favored by females for egg laying. The cicadas can do serious damage to fruit orchards and nursery stock. The effect on mature trees is minor, so MDC foresters do not recommended using pesticides.

"I tell people to hold off on using the insecticides on them because it kills the good bugs, like pollenating bees that pollenate our fruit trees," Peterson said.

One piece of advice he offers homeowners to protect their young trees is to wrap the bottom of the tree in aluminum foil.

"The foil acts as a barrier and it's slick so it keeps the cicadas from climbing up it to get to the tree," he said.

Small or newly-planted trees and shrubs can be covered with mesh and tied at the trunk. To reduce stress issues, homeowners should water young trees well during summer's hot and dry months, Lawrence said.

This emergence will not be as large as the one in 1998, but will still be noisy. Adults emerging from the nymph shells will be soft at first. But within hours their wings and exoskeleton will dry and harden. They will then begin making the next generation that will sing in 2032.

"Once they get out, they'll be singing in the trees for a while and make the racket," Lawrence said.

For more information on cicadas, Petersen recommends visiting the website, www.cicadamania.com, or to input cicada sound on www.youtube.com to hear how the insects sound.

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