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.

“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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Slippery spring saga

Post by Jen Berlinghof

It was late March, fourteen years ago, when I took my first hike at Ryerson Woods. The air felt heavy with thawing snow. The sun warmed my back for the first time in many months. Standing at the edge of a small, glistening pool of water in this oak flatwood forest, I saw my first blue-spotted salamander (Ambystoma laterale). About the length of a crayon, this inky black amphibian is adorned with tiny, blue confetti-like spots on a dewy body. Blue-spotted salamanders hide in abandoned mammal burrows or under logs most of their life. Each spring, warming temperatures and increased precipitation lure these creatures out of their covert caverns for a slow and steady march to their breeding ponds.

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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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Water Connects Lake County

It comes as no surprise that in a place named “Lake County” you are never more than a stone’s throw away from water. Lake County, Illinois is scattered with thousands of acres of wetlands, dotted with over 170 lakes and rivers, crisscrossed with 400 miles of streams, and bordered by massive Lake Michigan. This year at the Lake County Forest Preserves, we are celebrating this wealth of water by exploring how Water Connects Lake County through educational programs and recreational opportunities.

One way water connects the critters of Lake County is through the magic of metamorphosis. Ponds, streams and other wetlands host and hide well-known animals in surprising forms. Take a look at the picture below. This is a type of insect found in most local bodies of water. Can you identify this creature?

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