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.

Any ten-year-old child can probably identify the most common woolly bear larva in the area, the isabella tiger moth (Pyrrharctia isabella). It boasts orange and black bristles in a banded pattern. That same child may also try to convince you this critter can predict the severity of the coming winter by looking at the length of the caterpillar’s bands of bristles. But just as groundhogs can’t truly predict the spring, moth larvae cannot predict the winter. After each molt, a stripe of the black setae (stiff hairs) is replaced by orange setae. This makes the orange band broadest in the last instar, or stage of larval development.

The author holds a giant leopard moth caterpillar (Hypercompe scribonia) in her hand. Photo © Lake County Forest Preserves.

I found another type of woolly bear caterpillar on a recent hike at Ryerson Woods (Riverwoods) that might be less familiar to folks. The larva of the giant leopard moth (Hypercompe scribonia) sports shiny black bristles separated by red inter-segments. Like the isabella moth larva, this giant woolly bear lacks stinging spines and doesn’t bite. When alarmed, it curls up into a tight ball, displaying its setae like little swords that can irritate the skin and mucous membranes of potential predators. This defensive posture also makes its bright red inter-segments prominent, a literal “red flag” to warn predators they’re unpalatable.

In its defensive posture, a giant leopard moth caterpillar displays its stiff setae and red inter-segments. Photo © Donald W. Hall.

Once these woolly bears have gorged themselves on asters, milkweed, sunflowers, violets, and even dandelions—and almost finished growing as larvae—they ramble on to find a suitable spot under leaves or logs to wait out the winter. Unlike most moth larvae that spend our freezing months tucked inside a pupal “sleeping bag,” in general tiger moths overwinter as nearly full-grown caterpillars, pumping glycerol through their bodies to keep their cells from freezing solid. They then emerge in spring to munch a bit more before creating a cocoon and completing metamorphosis.

The familiar orange-and-black woolly bear caterpillar emerges in spring as an adult isabella tiger moth. Photo © Patrick Randall.

An adult giant leopard moth. Photo © Christopher J. Williams.

As the sun sets earlier in the final days of fall and winter approaches, take these last moments to try to find these fascinating larvae before they hide away and press pause on their development. Discover new trails with our Hike Lake County Challenge before it ends on November 30. Then, come spring, look for the adult moths when both larvae and people emerge to explore the new season.

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

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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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Final songs of summer

Post by Jen B

As summer winds down, a telltale hum that signals the changing seasons begins to ramp up in the fields and forests. These trills and chirps are the mating calls of tree crickets (Oecanthinae)—a group of fascinating insects that are often heard but seldom known or seen. Their small size and mint green color helps camouflage them amidst the verdant grasses, shrubs and trees of late summer.

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