Invasion of the 17-year cicadas is almost here

by Kate Evans

Get ready for the emergence and roar of billions of 17-year cicadas in our region.  The Brood X (10) periodical cicadas will start emerging from the ground here in mid-May. Warmer weather could start their emergence even earlier,  said West Virginia University Extension Service entomologist Dr. Carlos Quesada.

Quesada, Assistant Professor of the university’s Division of Plant and Soil Science, said that Brood X offspring from 2004 will emerge from the soil this spring. Some 15 states will experience the 17-year Brood X cicada invasion including West Virginia, Pennsylvania, Maryland, Virginia and Ohio, along with Washington D.C.  There are also 13-year cicadas.

Quesada said that these 17-year cicadas have orange eyes and orange in their wings with a black body. The annual cicadas have a green color in their body and wings along with a green head and thorax.

Quesada said there can be up to a million cicadas in an acre of land — nearly the size of a regulation football field.  Not all of the insects emerge at the same exact time. Some can even come a year early or a year late.

Life cycle

Their full adult life cycle goes for about six weeks. It starts around mid-May and runs through the entire month of June. The adult periodical cicadas mate, lay their eggs and die, becoming a layer of fertilizer for the forest canopy and fields.

The periodical cicada nymphs live underground for 17 years feeding on tree roots.  When they mature, they burrow to the surface, undergo a final molt and become winged adults, discarding their exoskeleton.  They live as adults for two to six weeks, mating and producing the next generation of cicadas.

Male mating song

Only the males sing to attract a female mate, Quesada said.

The males rapidly vibrate membranes called tymbals that are on either side of their body underneath their wings, creating a clicking, chirping sound.  A female can hear it up to a mile away.  The mating serenade can get quite loud — 80 to 100 decibels or more — comparable to a loud lawn mower.

The female periodic cicadas lay their eggs in slits they create in branches, Quesada said.    Each slit contains 20-24 eggs with five to 20 slits per branch. One female can produce 400-600 eggs. The eggs hatch within three to four weeks.  The newly hatched nymphs immediately tunnel down into the soil around one to two feet until they find tree roots to eat.

They’ve found trees whose roots are highly infested with cicada nymphs but the trees are fine — the nymphs don’t kill them, Quesada noted.  Cicadas eat very little over the 13-17 years they’re underground.

Protect fragile trees

Quesada said landowners can protect fragile saplings and young trees by putting netting or plastic mesh over them during the six weeks of the cicadas to keep the insects from harming them.

Usually big and well-established trees are not affected by the cicadas, but newly planted trees are in danger, he stressed.

Cicadas prefer branches that are the size of pencils for laying their eggs, Quesada said.  Young fragile trees will be highly damaged.  If planting new trees, it would be best to wait until July after the cicada life cycle is over.

Predators

Quesada said that bears, raccoons, squirrels and other animals are predators for cicadas.

Domestic cats and dogs may also eat cicadas.  Some fishermen use the cicadas for bait. Other predators include fish, snakes, birds, rodents and lizards as cicadas are in great abundance when they emerge.

It’s impossible for other animals to kill them all, so the cicadas survive to breed another generation, Quesada noted. Deforestation and wildfires can affect the cicada population in large areas or specific places.  While a couple of cicada broods have become extinct, cicadas aren’t considered endangered.  There are 10-14 broods.

A Cicada killer wasp also preys on the emergent insects and there is also the parasitic Massosphora cicadina fungus that is affecting the 17-year periodical cicadas.

Fungus

Dr. Matthew Kasson, West Virginia University Associate Professor of Forest Pathology and Mycology, and his team studied the Massosphora cicadina fungus on campus in 2016 when Brood V emerged in Morgantown.  The fungus is native to the United States and has been known since the 1800s, he said.

Less than 5% of the periodical cicadas become infected with the Massosphora cicadina fungus, Kasson said.

There’s no evidence to suspect that the fungus causes a shortened life span in the cicadas.  That wouldn’t be beneficial for the fungus, which just wants to reproduce.

Kasson said that female periodical cicadas have a sword-like ovipositor appendage on their back part for laying eggs.

“They need a sturdy needle-like organ to get the eggs in the bark,” he noted.

Kasson said that it’s most likely that the fungus spores make their way into the top foot of the soil and are transferred into the rice-grain sized nymphs as they come up from the lower soil. The fungus is also spread from a partner through mating.  Spores can fall off the cicadas and fungal residues are left on the branches like chalk.

Extinctions, forest health

Brood II, next year’s brood, has become extinct and Brood VII is close to extinction, he said.  Brood VII is in New York near Syracuse near Native American tribal lands. Land deforestation and clearing of large tracts of ground for housing subdivisions, shopping malls and parking lots kills the cicadas.

As a forest pathologist, Kasson and his department monitors storms, invasive species, tree health, forest ecosystems and insect pathogens.

“The forest is really important,” he stressed.

Pose no risk

The tri-state area should have billions of the cicadas surfacing from the ground soon. People will see holes in the ground of the cicada nymphs when they are ready to emerge.  The insects pose no danger to humans, Kasson said.

Kasson said that a lot of people are afraid of cicadas but “they don’t have the mouth parts to harm us.”  They will fly around you and at you, but they’re just big clumsy insects.  They may land on your shirt or in your hair, but they don’t pose any risk to people.

The periodical cicadas calling can be deafening, Kasson noted.  Some describe it as a song or it can be a humming.

“It’s a sight to be seen,” Kasson said of the cicadas’ emergence.

2 Comments

  1. Rhonda Condit on April 23, 2021 at 6:45 pm

    There shell reminds me of pork rinds.

  2. C. K. on May 15, 2021 at 11:43 am

    Are cicadas sought,to eat.
    Are they ‘tasty’?
    Have YOU ate one?

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