"A Trill of a Lifetime"

We immersed ourselves in the emergence, hiking toward the calling—louder, louder—I could hear at least two species singing and the air was full of dark bodies flying. Near a cherry tree you could hear the crescendo—loud then soft, loud then soft—better than any orchestra. We had the best seats in the “house”—our legs—as we experienced this 17-year symphony.

Northern Illinois Brood (XIII)

Palos Valley Forest Preserve Cook County June 2, 2007

Journal of Susan Post

by Susan Post

No other insects in North America excite as much curiosity and wonder as do periodical cicadas when they make their sudden appearance every 13 or 17 years. Periodical cicadas are widely distributed in the eastern United States (east of the Rocky Mountains), but occur nowhere else on earth There are seven species of periodical cicadas—four with 13-year life cycles and three with 17-year life cycles. The best way to identify the species is by sound as each species song is species specific.

After years of living in underground tunnels, thousands of periodical cicadas emerge from the earth as if by a predetermined signal, shed their nymphal skins, and spread through the nearby trees and bushes. Up to 40,000 can emerge from a under a single tree!

The cicada's precise but prolonged time schedule revolves around survival for the masses. When a large population of juicy insects appears on the scene, predators make the most of the situation, but simply cannot eat all the insects. Thus, a significant number of cicadas live to reproduce. Long-lived predators may actually remember the feast and return to the scene in subsequent years. Short-lived predators, being well fed, from the cicada banquet, reproduce successfully and leave a large population to await the next year's emergence. However, the “next” emergence doesn't happen for another 13 or 17 years, so the periodical cicada is able to outlast and escape its enemies.

From morning 'til night the males fill the air with their loud, droning song. The song is like the familiar sound of the common, dog-day cicada that fills the summer evenings, only it is louder and heard at the end of spring. (See our article on Summer Cicadas). The males are the only ones singing.

During 2011 The Great Southern Brood (XIX) will emerge. Their deafening drone will perk up woods from Illinois to Louisiana and Virginia to Georgia. There are 15 broods of cicadas in North America—twelve 17-year broods and three 13-year broods.

Periodical cicadas spend 13 or 17 years eighteen to twenty-four inches deep in the soil of wooded and forested areas feeding on sap from tree roots. They dig their way out of the soil during late May and June and climb up tree trunks, posts and poles to molt into adults. The adult insect is about one and a half inches long with a black body, red legs, and red eyes. They have piercing and sucking mouthparts and will feed on a variety of woody vegetation. Each adult may live five or six weeks, they will mate, and the female will pump her egg in slits of small twigs and shrubs using her sickle-like ovipositor. (This will cause some twig dieback but no long-term consequences to the tree.) The eggs will hatch after six to seven weeks and the newly hatched nymphs (about the size of an ant) fall to the ground and burrow until they find a suitable tree root, where they feed and wait. The nymphs will undergo five molts in their 13 or 17 years.

Perhaps Aldo Leopold described them best when he talked about the passenger pigeon—They traveled the countryside this “traveling blast of life;” like Leopold’s pigeons they will also disappear, unlike the passenger pigeon however, the cicadas will return. If you are an eager periodical cicada watcher, you need not despair as you wait for the next emergence in 13 or 17 years. Several broods of both 13 and 17 year cicadas are found in Illinois, so every few years, if you are willing to travel a little, can provide a periodical cicada viewing opportunity and as an entomologist from Iowa states, “a trill of a lifetime!”

Side bar

A cicada emergence is something that must be experienced. Brandi Sangunett, a masters student in Natural Resources and Environmental Sciences at the University of Illinois, had the opportunity to experience just such an emergence during Memorial Day, 1998. " My husband and I went camping at a beautiful place called Pounds Hollow in southern Illinois. The trees around the campground were littered with the shells of cicadas; the ground was covered with tiny holes from which they left their terrestrial homes and began an arboreal existence. At night, as we were sitting around the campfire, they began coming out of the ground in droves. They crawled up any upright object, including our legs, to molt from their last instar into adulthood. They also began falling from the trees as they lost their footing and pummeled us like dive-bombers. As we slept in our tent, we could hear them crawling up the sides. After they reached a suitable place under our rainfly, we could hear them cracking open. They emerged as white, ghostly aliens and slowly unshriveled into eerie black creatures with demon-red eyes. In the morning as I began taking down the tent, I removed the rain fly and a gaggle of them escaped into the trees. The air was filled with an ominous humming which could be heard for miles around. The entire forest sounded like a huge machine or like the hum of buildings in a city.”

Heron Pond

by Susan Post

Long before human records were kept, the extreme tip of southern Illinois bordered the shoreline of a much larger Gulf of Mexico. Though the seas retreated, plants and animals remain in southern Illinois that are more commonly found surrounding the present day Gulf of Mexico. Heron Pond, located in Johnson County, provides a glimpse into this ancient landscape.

In this strange, silent, primeval world of the southern swamps, the only sounds one hears are created by humans or birds: the groan and creak of the floating boardwalk underfoot, a pileated woodpecker hammering on a long-dead snag, a prothonotary warbler chortling as it feeds its young, or the startled cry of a wood duck fleeing through the trees. Cypress trees, in a seemingly vast stand, support upon their "knees" little colonies of plants —islands in miniature. The surface of the pond is covered with several species of duckweed. This thick green blanket is broken only by a fallen cypress needle, the black ribbon of a swimming cottonmouth, or the delicately embossed outline of a floating frog. In the quiet and stillness, the bayous of Louisiana come to mind.

This area was originally described by an English journalist in the 1860s as "a forest of dead trees—a cheerless miserable place, sacred to the ague and fever." Other early visitors described it as a place where your first and only thought was "how shall I get away again" or more simply, "the pit of hell." These descriptions of the swamps of southern Illinois, of vegetation more typical of Mississippi, Alabama, or Louisiana, were made by individuals viewing the landscape without the luxury of a boardwalk.

Heron Pond, located 1 mile northwest of Forman, Illinois, is a bald cypress forest named for the great blue herons that nested in the huge cypress trees. It is part of a larger area called the Cache River State Natural Area. The trail at Heron Pond begins west of the parking lot. Crossing the Upper Cache River on a suspension bridge, you enter the bottomland forests, soon leave them behind, and enter the world of the swamp.

In spring, the trail is lined with wildflowers; by August the huge white blossoms of spider lily have opened, creating patches of white in the unrelenting green. By late fall the cypress trees have discarded their needles, littering the duckweed with brown. Fortunately, your adventure into the swamp is greatly aided by a long boardwalk.

Though the southern swamp, with its midsummer heat, humidity and mosquitoes, could still be called "the pit of hell" by the unprepared, the sights and sounds of this unique landscape soften this unfortunate description for most, and a visit to Heron Pond becomes an adventure into the remote past.

Prairie Pages

Here is an article by Sue Post published in the Illinois Steward, Spring 2009 issue about a few of our favorite Illinois Prairie sites (click download or fullscreen for better readability):
Prairie Pages

“We Sweated and Survived”

We finished up our Dragonfly Blitz on Thursday, 29 July, visiting parts of Wildcat Hollow. Within 15 minutes of our arrival at the marsh, we spotted the elusive Comet Darner – a red beacon. And just like that, it was off, taunting us, daring us to catch it. Peering through binoculars from shore, ecstatic cries, “it’s coming right at you!” “to your left!” “on your right!” only seemed to confuse those standing with their nets at the ready. Skillfully, the Comet Darner snatched a saddlebag dragonfly and zipped off to the prairie.

Our skipper and moth expert, Jim Wiker, refused to give up, and after stalking it through the tall grass, returned with the Comet Darner in hand for all to admire.

Grand Total: 21 Species of Dragonflies

A few photos from the class:

IWIN Dragonfly Blitz Day 2

After our second day of the blitz, with heat index of 109, we are up to 29 species of butterfly and 20 species of dragonfly.

Today we visited Fulfer Creek and the Daybreak Sanctuary adding:

Mocha Emerald
Swift River Cruiser
Flag-tailed Spinyleg
Great Blue Skimmer
Blue-faced Meadowhawk

Tomorrow is our last day; fingers crossed for good weather and a few more species to add to our list.

We'll have plenty of pictures to post when we get back to the office!

Illinois Wilds Institute for Nature Dragonfly Blitz

"They're the greatest mathematicians. They can estimate the length of your net and add 18 inches." Richard Day

Thirty-two participants will spend three days in east-central Illinois trying to see as many species of dragonflies as possible.

Our first day, it was 90F and 75% humidity. At Ballard Nature Center in Altamont IL, we found 15 species of dragonfly:

Green Darner
Eastern Pondhawk
Slaty Skimmer
Twelve-spot Skimmer
Black Saddlebag
Carolina Saddlebag
Red Saddlebag
Halloween Pennant
Calico Pennant
Whitetail
Widow Skimmer
Eastern Amberwing
Spot-wing Glider
Blue Dasher
Spangled Skimmer

Tonight we blacklight for insects!

Summer Cicadas

by Susan Post

Late evening of the hot days of summer is the perfect time to hear the loud drone of male cicadas. Even during classical times the fact that only male cicadas produced sound was well known, leading to the chauvinistic comment—"Happy are the cicadas for they all have voiceless wives."

After spending anywhere from one to six years underground as a nymph, cicada males loudly announce their arrival upon the scene. The call is produced, not by rubbing wings or legs together, but by muscles vibrating a pair of drum-like membranes in the cicada’s thorax. An air cavity acts as a resonator and connects to the outside through a pair of tiny holes called spiracles.

While many of us may be familiar with the dog day or annual cicadas found in our yards—prairies also support cicadas. People who've seen this insect in high quality prairies say they “fly up like partridges when disturbed.” The adult prairie cicada's body is large, approximately one and half to two inches long and brownish yellow with conspicuous brown and white markings. Prairie cicada nymphs, instead of feeding on the roots of trees like their city and forest cousins, prefer to suck the sap of the long roots of prairie dock and compass plant.

Whether you hear the drone of the cicadas in your backyard or on the prairie, recognize it for what it is and enjoy this brief, poignant, noisy love serenade of summer.