Cicadas 2021

The 17-year cicadas [such as Brood X] are species of periodical cicadas, a group of homopterans with the longest known insect life cycle. The largest brood makes its appearance every 17 years, like clockwork, in the northeastern quarter of the United States. Shortly after a 17-year cicada nymph hatches from its egg, it burrows into the ground, where it spends - as its name suggests - the first 17 years of its life. When it emerges from the ground, it lives only four to six more weeks - just long enough to mate, fertilize or lay eggs, and start the cycle all over again.
- from Britannica - Why Do Some Cicadas Appear Only Every 17 Years?

Inch-long cicada nymphs excavated these tunnels that took them to the surface. Since 2004, they have been growing and molting, drinking a fluid called xylem from plant and tree roots through a straw-like beak.

When the soil about a foot below ground warms to 64 degrees, probably on an evening that is humid but calm, they crawl out. Half the brood emerges within a couple of weeks.

How do the cicadas know when 17 years have passed? Though no one theory has been proven, many scientists speculate that periodical cicadas possess an internal molecular clock that notes the passage of years through environmental cues. As trees go through their seasonal cycles, shedding and growing leaves, the composition of their sap changes. And when cicada nymphs feed on that sap, they likely pick up clues about the passage of time. The 17th iteration of the trees’ seasonal cycle gives the nymphs their final cue: it's time to emerge.
- from Britannica - Why Do Some Cicadas Appear Only Every 17 Years?

Once out, the nymphs climb something vertical - the nearest tree, flower, wall or pipe will do - and molt for the last time.

After wriggling out of its brown shell, it is now over an inch long and almost completely white, with the bright red eyes that identify it as a periodical cicada. It is extremely soft and vulnerable, a tasty snack for birds, dogs and other creatures.

I tried a couple myself at Cicadafest in Fulton, Maryland on May 22, 2021. They were cooked in a hot air fryer. Dipping sauces were available. Without the sauce, they didn't have much flavor. I think they would have been fine mixed in with pasta. Some people compare the taste to canned asparagus.

Cicadas are practically defenseless. They don't bite or sting and they're not poisonous. Their primary defense against predators seems to be their sheer numbers during their synchronized emergence. If they come out in greater numbers than can be possibly consumed by the predators present at that time, then more of them will be likely to avoid predation and find a mate. This is exactly what they do, emerging at densities of over a million per acre.
- from Nature - Cicadian Rhythms: Why Does the 17-Year Cicada Emerge Like Clockwork?

17 year and 13 year broods co-emerge every 221 years. Cicada broods usually don't overlap geographically, and it is very rare when they emerge in the same year. The next time Brood II (the brood emerging in 2013) will co-emerge with another brood will be in 2115 when it co-emerges with Brood XIX. You might need a time machine to see that happen.
- from Cicada Mania

I was told there are no 13-year cicadas in Maryland.

After transforming into a young adult or "teenager," the cicada leaves the external skeleton of its nymph behind.
In biology, exuviae ["exuvia" is singular, "exuviae" is plural] are the remains of an exoskeleton and related structures that are left after ecdysozoans (including insects, crustaceans and arachnids) have molted.
- from Wikipedia - Exuviae


Dragonflies, damselflies, stoneflies, and mayflies also leave behind these ghostly but tangile shadows of their former selves.
- from Bug Eric - Cicada Shells

I found numerous exuviae attached to the hardware cloth wall of my chicken run, along the curb, on trees, and at the base of trees.

Maybe you've seen them in your neighborhood: A white or cream-colored cicada with beady red eyes.

No, they're not albino cicadas. They're just teenagers, many just emerging from their nymphal skin.

When cicadas first shed their exoskeleton, they may appear a bit white.

But they slowly change color as their adult skin hardens, their wings will inflate and then they'll start to sing.
- from WLWT5 - White cicadas in Cincinnati: No, they're not albino

Freshly molted, they are white and soft-bodied, but within a week, their bodies darken and harden, allowing them to fly and make that distinctive cicada sound with their thorax.
- from Nature - Cicadian Rhythms: Why Does the 17-Year Cicada Emerge Like Clockwork?

After moulting, an arthropod is described as teneral; it is "fresh", pale and soft-bodied. Within one or two hours, the cuticle hardens and darkens following a tanning process analogous to the production of leather. During this short phase, the animal expands, since growth is otherwise constrained by the rigidity of the exoskeleton. Growth of the limbs and other parts normally covered by hard exoskeleton is achieved by the transfer of body fluids from soft parts before the new skin hardens.
- from Wikipedia - Ecdysis

The vast majority of these cicadas have orangish-red eyes. A few mutants can have blue or white eyes, though this is uncommon. Cicadas have five eyes - two large red ones with three small, dark colored eyes in between.
- from National Park Service - Brood X Periodical Cicadas FAQ

The three jewel-like eyes situated between the two main, compound eyes of a cicada are called ocelli. We believe ocelli are used to detect light and darkness. Ocelli means "little eyes" in Latin.
- from Cicada Mania

I am still looking for a blue-eyed cicada.

In a few hours after its last molt, its body will turn bluish black and orange, like other members of Magicicada septendecim, the largest of three Brood X species. In several days, it will be able to fly - and call.

Some cicadas have shriveled-up or otherwise damaged wings. Most of the time, wings become damaged during the molting process (ecdysis), specifically while their wings harden (sclerotize). Their wings and body are most vulnerable when they are still soft.
- from Cicada Mania - Why do some cicadas have shriveled up or damaged wings?

Since many cicadas must crawl onto the same places, they often bump into or climb over each other. This is a problem for those light-colored, recently molted cicadas who are waiting for their exoskeletons to harden. At the delicate stage when they must hang undisturbed, they are finding themselves trampled by other cicadas. This causes the many deformed cicadas.
- from Celebrating Randomness - So Many Deformed Cicadas

Deformed cicadas are typically eaten quickly by predators since they cannot fly as well as normal cicadas.

"Swarmageddon" produced far more cicadas than predators could eat during their short visit. Norma observed that her sour cherry tree produced more fruit than in previous years, likely because birds were favoring eating cicadas over the cherries. Unfortunately, my chickens were still young and didn't make it out into the back yard until the cicadas were almost gone. But at least they got to sample a few.

Adult cicadas are only around for a few weeks before they die. Their mission is simple...perpetuate the species. To do this, they first need to find a mate by making a lot of noise.
Male cicadas produce the loudest sounds in the insect world. Entomologists believe that the sound protects these insects by hurting predators' ears.
- from National Park Service - Brood X Periodical Cicadas FAQ

"They are screaming at about 96 decibels. That's louder than the jets flying into Heathrow," says Kritsky [an entomologist at Mount Saint Joseph University]. Indeed, prolonged exposure could cause permanent hearing damage.
- from The Guardian - Sex-mad and spectacular: 17 incredible facts about cicadas

Only males can call, using vibrating membranes called tymbals on either side of their hollow abdomens.

They call for different reasons; if you pick one up, you may hear an alarm squawk. But the main reason for calling is to attract females. Around dusk each evening, cicada will add its call to a chorus of other males hoping to find mates. Each species’ chorus has a distinctive sound.

When a female is interested, she will respond with a wing flick, which sounds like a snap. The male will notice and fly toward her, changing his call to a more complex one.

With each call and flick, he will approach closer. The female listens for acoustic cues to make sure he is the right species. Competition can be fierce, and a rival male may try to drown out his song.

Once he is very close to the female, he will stop calling and begin to touch her with his forelegs. If she is receptive, they will mate, tail to tail. A male can mate many times, but a female usually mates only once.

Within an hour after mating, the female will find a tender tree branch and slice it open with her swordlike ovipositor. She will insert up to 30 eggs, then make more slits until she has deposited a total of 400 to 600 eggs.

This is a branch from our Asian pear tree that was cut open by a cicada. Eggs are not visible here.

The cicada and its mate will die after two to four weeks above ground. Their nitrogen-rich bodies make excellent fertilizer.

Ends of tree branches will typically turn brown and die from cicadas laying eggs. Fortunately, this kind of stress only occurs every few years.

Six to 10 weeks later, tiny nymphs will hatch and drop to the ground. They will burrow below with their mole-like forelegs, latch onto a root and begin to feed and grow. If you're in the area, be sure to look for them in 2038.