Little Clay Pots

In late April, little clay pots appeared on our forested trails.  Thumb-sized and sturdy, most were circular but some were oval-shaped.  Never before had I seen such constructions.  Near some of them, I also found small holes deeper than my forefinger could penetrate.  It was as if some tribe of lilliputians had emerged from the ground and secretly constructed them of mud, tiny stones, and bits of moss.

After studying dozens of the clay pots and finding acorns in some of them, I decided that they had somehow formed around squirrel-buried acorns and, in removing the acorns, the squirrels had uncovered the clay pots.  I contacted my favorite squirrel researcher and showed her the clay pots.  But she too had never seen anything like them.

The auhtors collection of mysterious pots

The author's collection of mysterious "pots"

The artistry and diversity of the pots fascinated me. I filled a shoe box lid with them and put them on my desk.  Sooner or later, I hoped to find out what they were.

It turned out to be sooner.  On June 7, the second day of heat and humidity, our son Dave showed me photos of the little clay pots on the Penn State University Entomology Department’s website. They had been constructed by the nymphal stage of Brood XIV of the periodical cicada. Brood X, known as “the great eastern brood,” had emerged in many Pennsylvania counties, including our own, in 2004, but on our mountain, only Brood XIV, the second largest brood of periodical cicadas in Pennsylvania, emerges.

“In April, they [the nymphs] burrow to about an inch beneath the soil surface,” Senior Extension Associate Greg Hoover wrote on the Penn State website, “where they stop and await the proper time to emerge. If the ground is too damp, [as it was in April] mature nymphs build a protective earthen turret.”

But I wondered why I hadn’t seen them during the two previous emergences of Brood XIV on our mountain in 1991 and 1974. I e-mailed David Marshall, an expert on the periodical cicada at the University of Connecticut, for more information.

Cicada on the powerline right-of-way

Cicada on the powerline right-of-way

“No one knows for sure why the cicadas build the turrets when they do,” he answered.  “Most of the time they do not, and yet sometimes a whole area will have them built way up several inches.  Theories range from differences in soil moisture/recent rainfall (nymphs somehow reducing the risk of drowning) to artifacts of differential exposure to light.  People were writing about this 100 years ago in USDA publications, and we have hardly learned any more since then!”

Furthermore, Marshall had no idea who or what had knocked all the tops off the turrets and why some contained acorns.  Neither did any other expert I consulted.  So I had to be content with solving half the mystery of the little clay pots.

We had started to hear the “phar-oah” calls of Magicicada septendecim, one of the three species of Brood XIV periodical cicadas, drifting up from bucolic Sinking Valley 500 feet below our mountaintop, a week earlier.  The day before we partially solved the mystery of the clay pots, Dave had reported that the periodical cicadas were emerging on the powerline right-of-way.  Summer had arrived with a vengeance and clad only in shorts and tank top, I hiked to the top of the right-of-way to welcome back the longest-living insects in North America.  Although I could hear the cicadas screeching down in the valley, those on the right-of-way were silent.

With their red eyes, golden-edged translucent wings segmented like stained glass windows by narrow bands of black, and the first segment of each leg the same orange-red as their eyes, they are strikingly handsome creatures.  They flew up from the scrub oaks and spun head-on toward me, veering off only at the last minute, their wings flashing in the sunlight.  Seemingly lurching under their own weight and barely able to maintain their equilibrium, they reminded me of miniature, poorly-loaded cargo planes.

Cicada on scrub oak

Cicada on scrub oak

Still known erroneously by many people as 17-year locusts, the more than 2400 species of cicadas worldwide belong to the insect order Homoptera, whereas locusts are members of the Orthoptera insect order.  Back in the spring of 1634, when they emerged in Massachusetts, the pilgrims called them “locusts” because of their overwhelming numbers, which reminded them of biblical plagues of locusts.  They had never seen any insects like them because periodical cicadas occur nowhere else in the world but in eastern North America.

The Royal Society of London Journal reported this plague and wrote “that for the space of 200 miles they poisoned and destroyed all the trees of that country; there being found innumerable little holes in the ground, out of which those insects broke forth in the form of maggots, which turned into flyes (sic) that had a kind of taile (sic) or sting, which they stuck into the tree, and thereby envenomed and killed it.” Thus, the misnomer of “locusts.”

However, the truth about these insects is even more amazing than the folklore. Because cicada larvae have sucking mouthparts, they are closely related to aphids, scale insects, mealy bugs, tree and leaf hoppers.  Their small, fishlike larvae use sharp beaks to puncture tree rootlets and suck watery liquid out of them as sustenance during their 17 years underground. When one rootlet dies, they move on to another.

After more than ten years as deep as two feet underground, they move closer to the soil surface.  One researcher, Monte Lloyd, back in the early 1960s, dug up the larvae at various stages and found that they take a four-year rest during their underground growth.

It is probably the soil temperature — around 64 degrees Fahrenheit — that finally triggers the larvae to emerge from their tunnels after sunset, climb a shrub or small tree, and wriggle out of the exoskeleton of their fifth instar or juvenile stage.  The adults are white when they first appear, and cicada connoisseurs recommend eating them at that stage either plain or sautéed in butter and parsley.

Empty cicada exuviae on the powerline

Empty cicada exuviae on the powerline

“They have a nutty flavor, almost like a pistachio nut,” writes David George Gordon in his The Eat-A-Bug Cookbook, while Monte Lloyd says “they taste like a cross between an avocado and a raw potato” and maintains that they are delicious.

Even after they harden, in a day or so, they are excellent food for spiders, snakes, birds, and fish.  The largest wasp in the East — the cicada killer — paralyzes a cicada with its sting, pulls it up into a tree, flies to its nest still holding the cicada, and feeds it to its wasp larva.  But because of the cicadas’survival strategy called by researchers “predator satiation” or emerging in overwhelming numbers as high as 1.5 million per acre, predators couldn’t begin to eat all of them.

A predator fungus, though, Massopora cicadina, that infects the larvae as they burrow into the soil, can be a problem to populations.  The fungus stays with the larvae when they emerge 17 years later and while infected females mate, they don’t lay eggs. Infected males try to mate with both males and females.  This spreads the fungus.  But most cicada populations are fungus-free and perform as they should to perpetuate the species.

After four days of hardening and rest, the males form aggregations, also referred to as choruses or leks that sexually attract females.  There are actually three species of 17-year periodical cicadas, and their calls are their best identifying characteristic.  The most common is the “phar-oah” calling M. septendecim, followed by the ticking and buzzing of M. cassini, and the much rarer M.septendecula, which sounds like a lawn sprinkler.


Video link.

The males produce their songs using ridged membranes on the first segment of their abdomens, which are hollow and probably act as resonating chambers.  The silent females hear them through their tympana or ear drums–membranous organs located on the undersides of their abdomens.

The aforementioned David Marshall and John Cooley caged unmated females and after several days, when the females could hear calling males, they flicked their wings.  Evidently, males end each of their screeches with a downward slur.  If a female is interested in a male, she then flicks her wings.  The favored male makes a buzzing sound meant to keep other males away.  Then he changes his song into courtship mode and, if that works, the female allows him to approach her, whereupon the male performs a final serenade before mating.

All this singing drives many humans to distraction. Some even lock themselves in their homes and call the fire department.  But I enjoyed moving from the lek on the powerline right-of-way to the chorus at the top corner of First Field to another aggregation at the Far Field.  As dawn strengthened every day, the tide of sound began, swelling to a crescendo as the day progressed, fading away to a diminuendo and then a numbing silence at daylight’s end.  After three weeks, the sound became an integral part of my life.

A female cicada deposits eggs in a black locust branch

A female cicada deposits eggs in a black locust branch

But even while some males continued to sing, I watched the females scrape Y-shaped egg nests in scrub oak branches on the powerline right-of-way with their long, black ovipositors, and, pumping their hind ends, deposit up to 20 eggs per nest.  A single female lays as many as 600 eggs in multiple nests.  Sometimes those nest-filled branches will break off and drop to the ground, but, for the most part, “nature’s pruners,” as periodical cicadas are sometimes nicknamed, do little harm to trees.  Even the adults’ feeding by sucking plant fluids during their four weeks aboveground, is relatively harmless to the plants.

By the first of July, most of the singing was over.  In six to seven weeks the eggs would hatch and the white, antlike nymphs would wriggle out of their nests, drop to the ground, and burrow into the soil.

Altogether, I enjoyed hearing and seeing my third emergence of Brood XIV on our mountain. Had I been born here I would have heard the 1940 outbreak a month before my birth, their thrumming calls reaching me through my mother’s womb.  The next outbreak–in 1957–would have occurred the June I finished my junior year in high school.  We had lived on the mountain three years and I was 33, at the peak of motherhood, my three little boys excitedly collecting cicadas in glass jars, when they emerged in 1974. During the 1991 emergence, the boys were off on their own, and I was 50 years old and busily engaged in my writing career. Last June I was 67 and, like William T. Davis, the so-called Cicada Man of Staten Island, who identified and named half the cicada species in North America, I have been pleased to track my life through Brood XIV periodical cicada outbreaks.  Such tracking gives me a keen sense of my own mortality.

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For more information (and entertainment), consult cicadamania.com.  This website, started in 1998, is “dedicated to cicadas, the most amazing insects in the world.” They post photos and information about cicadas from as far away as Australia, and they diligently track the major broods of periodical cicadas in North America.

The Penn State webpage includes a timetable of expected appearances of the periodical cicada in Pennsylvania and the counties in which they may emerge.

The wings of cicadas eaten by predators litter the trail above the garage

The wings of cicadas eaten by predators littered the trail above the garage

All photos and video shot on Brush Mountain, June-July 2008, by Dave Bonta