The din of the dog days

Post by Jen Berlinghof

The dog days of summer are a bounty for the senses. We see the lemon-yellow of whorled sunflower blooms, taste the ripe flavor of a homegrown tomato, smell the spicy sweetness of bee balm flowers, feel the heat of the day and the cool of the evening. Yet the most quintessential sensation of these end-of-summer days is hearing the overwhelming cacophony of cicada songs around the Lake County Forest Preserves in northern Illinois.

When we talk cicadas, the first questions that often come to mind concern periodical cicadas that emerge en masse every 17 years. This phenomenon is fascinating, but our last emergence of Magicicada occurred in 2007, so we will have to wait until 2024 to experience that spellbinding season again.

The cicadas we hear now, and indeed every summer, are considered annual cicadas. While their lifecycle actually lasts anywhere from two to five years, they’re not synchronized, so we end up hearing and seeing some each year.

Whether periodical or annual, all cicadas go through the same basic lifecycle. A female deposits rice-shaped eggs into grooves on small branches. She makes these grooves with her sharp ovipositor, a sword-like organ that extends from her abdomen for this purpose. Later, teeny cicada nymphs hatch out, then plummet to the ground and burrow in the soil in search of a root to feed on. They start with grass roots, and as they grow and molt, the nymphs eventually work their way up to a host tree root where they’ll sip away at sap for years.

When it’s time to emerge, cicada nymphs claw out of the dirt and head for higher ground to complete one final molt: shedding their exoskeltons. The exoskeletons, or what my kids always called “cicada coats,” remain on tree trunks and tall grasses long after the cicadas’ wings have inflated and they’ve flown away to complete their courtship and mating rituals.

The most obvious of those rituals is the mating songs of the male cicadas. These “true bugs” sing with their tymbal, an organ with a series of ribs that buckle when the cicada flexes its muscle. Like a bendy straw being pushed together and pulled apart, each snap of a rib collectively creates the loud, buzzing song.

And loud it is, sometimes reaching up to 100 decibels, the same intensity as a motorcycle rumbling past on a warm summer night. It may seem strange—and deafening—that a cicada sports exposed eardrums on its abdomen right next to the tymbal. But nature has figured out a workaround; just as male cicadas start to sing, a small muscle folds the eardrum shut.

You might have noticed the cicada chorus isn’t monotonous. It includes a variety of buzzing, clicking, and grinding noises. There are actually more than 190 species and subspecies of annual cicadas throughout North America. In Lake County, we commonly hear three species. The dog-day cicada (Neotibicen canicularis) sounds like a buzzsaw and tends to sing during the heat of the day. The scissor-grinder cicada (Neotibicen pruinosus) sings its grinding song from late morning until dusk. And Linne’s cicada (Neotibicen linnei) sounds like a whirring rattle all day long.

For better or worse, our eardrums don’t fold shut when cicada songs really get going. It’s worth keeping in mind, though, that what may seem like racket to us is sweet music to female cicadas’ ears. Enjoy the crescendo of the chorus in these dog days of summer.

Leopards and tigers and bears!

Post by Jen Berlinghof

Around the first frost is the best time for spotting bears in the Lake County Forest Preserves in northern Illinois…woolly bears, that is! These fuzzy caterpillars succumb to a late fall wanderlust and can often be found traversing trails and roads, as well as climbing vegetation and nibbling a last few bites before winter sets in. They belong to the subfamily Arctiinae, commonly known as tiger moths. Their scientific name stems from the ancient Greek word arktos (“bear”), for the appearance of their hairy larvae.

A woolly bear caterpillar (Pyrrharctia isabella) found along the Des Plaines River Trail. Photo © Lake County Forest Preserves.

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Summer “buzz kill”

Post by Jen Berlinghof

The sun had set, the campfire was doused, and the food was stashed away for the night as my sons and I tucked ourselves into our sleeping bag cocoons, thoroughly exhausted in a way one can only be from a day spent entirely outdoors. Still, sleep would not come easily. The whirling drone of thousands of annual cicadas buzzed through the nylon walls of our tent loud enough to overpower our fatigue. I lay awake, thinking it odd the cicadas would be calling after dark, when I caught a hint of the rising full moon through the ceiling screen and realized they were staying up late to party with the extra light. One of my boys groaned, “Isn’t there anything that can stop these CICADAS?” As a matter of fact, the next day we found just the thing: a cicada killer wasp (Sphecius speciosus).

The author holds a dead cicada killer wasp in her palm. Photo © Lake County Forest Preserves.

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“Submarine cottages”

Post by Jen Berlinghof

Late spring and early summer are busy seasons for children visiting the Lake County Forest Preserves for pond study programs. The shorelines of ponds pulse with the excitement of students, nets in hand, ready to discover the macroinvertebrates teeming under the water’s surface. The most delightful find this season by students has to be what Henry David Thoreau once called the “submarine cottages” of caddisfly larvae.

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Dwindling lights

Post by Jen Berlinghof

At a recent Firefly Campfire at Ryerson Conservation Area, kids and adults alike were flitting around, as fast as the fireflies they were trying to catch. For many of the children, this was their first time experiencing the age-old summer tradition of capturing living light. While the woods that night sparkled like the fourth of July, many of the adults lamented that their yards didn’t have many fireflies—certainly not like the numbers they remembered chasing as children. Turns out they may be on to something.

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Widespread anecdotal evidence of these dwindling evening displays have prompted scientists to take a look at possible reasons. One big culprit to the demise of these bioluminescent beetles seems to be the one thing that makes them so special: light. Continue reading

Des Plaines River Trail—Kilbourne Road to Independence Grove

Post by Jen BerlinghofIMG_7700

Our adventure to traverse the entire length of the Des Plaines River Trail continued with our trek from Kilbourne Road to Independence Grove Forest Preserve under the shining sun and heavy air of late summer. The air was heavy not only with humidity, but with the calls of cicadas, tree crickets, and katydids melding into a three-part harmony that signaled the end of summer. The air was also pregnant with the perfume of flowering plants. It was clear that this hike belonged to the bugs and blooms. Continue reading

Acorn abodes

Post by Jen B

My family went on a bike ride last weekend at Ray Lake Forest Preserve. All afternoon, rain sputtered on and off as the clouds played tag with the sun. After climbing up a steep hill, the sky darkened again and we sought refuge under a canopy of large oak trees. One of my sons yelped,”Ouch! That raindrop hurt!” We quickly realized it wasn’t a raindrop, but a storm of acorns jiggled loose by the wind, plopping down on us. The trail became littered with acorns, and the kids began grabbing them. Upon inspection, the boys noticed tiny round holes in many of the acorns—evidence that these nuts were homes to acorn weevils (Curculio spp).

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