Stony Creek Ravine: Insects! The Good, the Not-all-Bad, and the Really Ugly

Stony Creek running fast and furious through the ravine after the many rain storms.

I’m sure you must have noticed. Insects are having a fabulous summer. Ticks are poised at the edge of tall grass, their back feet planted, their front ones waving about, trying to hitch a ride on anything that passes. Mosquitoes are reproducing like mad in any of the available standing water left by the repeated deluges that we’re experiencing. It’s not a pretty picture for us humans! But it can be, if I look more closely.

Text and photos
by Cam Mannino

This last few weeks I’ve explored the small, older section of Stony Creek Raving Nature Park, the western trail from Knob Creek Drive on West Gunn that leads to the Ravine itself. Armed with Deet, I wanted to see if I could find some beautiful, or at least interesting insects that would give me a break from the not-so-lovable ones! So here’s what I found, for better and for worse…

The Trail Begins in Sunny Meadows Filled with Wildflowers

The Meadow is lavender with Bee Balm blossoms and complemented by dashes of orange from Butterfly Milkweed.

Mottled sunlight slips over your shoulders when you first enter this area of the park. On one of my many visits between the downpours, I saw a flash of orange among the shadows which turned out to be the Gray Comma (Polygonia progne). It looks very much like the autumn coloring of the Eastern Comma (Polygonia comma); since it’s summer, it had to be the Gray Comma. These butterflies emerge from within logs or from under tree bark in April and mate. This Gray Comma would be the offspring of those that overwinter. It will produce a generation which will fly in August or September and hibernate to start the cycle again.

The Meadow Trail: Butterflies, Dragonflies and Rolling Meadows of Wildflowers

Foraging Butterflies

Once out in the open meadows, I paused to appreciate the frenetic flight of the Great Spangled Fritillary (Speyeria cybele). It dashed across the field, landing for a few seconds, then fluttering off again just above the flowers. Their caterpillars have a fondness for Common Blue Violets (Viola sororia), so they will occasionally appear on lawns. In our parks, they prefer native Wild Bergamot/Bee Balm (Monarda fistulosa), thistles and milkweed, according to the Butterflies of Michigan Field Guide by Jaret C. Daniels.

The Great Spangled Fritillary gets its name from the shine of the large silver spots on its hind wings. Here it’s sipping from Butterfly Milkweed.

Aren’t you always happy to see Monarch butterflies (Danaus plexippus)? The one my photographer friend Paul and I saw in the meadow arrived from somewhere between Mexico and Michigan, wherever its forebears stopped to lay eggs. With luck, this one will help set in motion the “super generation” of Monarchs; they make the whole 3,000 mile journey to Mexico where they overwinter. For lots more details on Monarchs, check out the blog that features them.

Paul and I hoped this Monarch would lay eggs for us on this Butterfly Milkweed. No luck that day. Photo by Paul Birtwhistle.

Territorial Dragonflies

Dragonflies patrol over the meadows as well, zinging here and there in an effort to establish territory and find a mate. The striking male Blue Dasher (Pachydiplax longipennis) with a green face zipped by me, but it was the juvenile Dasher who settled on a stick. It has the coloring of a female, but a much slimmer body than an adult. The female Dasher lays her eggs by flying over still water and repeatedly dipping her ovipositor into the surface to release her eggs.

Another denizen of the fields, the Halloween Pennant dragonfly (Celithemis eponina) foraged with a bouncy flight. These small dragonflies stay aloft more easily on windy days than other dragonflies and can even fly in light rain, shaking the water off their wings in flight. This one insisted on looking straight at me until it zoomed away. Luckily you can still see its vivid coloring and the huge compound eyes on either side of its head (with nearly 30,000 lenses). Two of its three simple eyes shine above; they’re believed to improve its navigation in changing light and also may help stabilize them as they speedily change course above the greenery.

The brown wing patches on the Halloween Pennant’s wings are thought by some to shade its body on hot days.

Two other dragonflies kept me company on the meadow. A juvenile male Common Whitetail (Plathemis lydia) followed me along the path, evidently hoping I’d stir up some insects that it could snatch from the air. And several Widow Skimmers (Libellula luctuosa) bobbed among the grasses on every trip to the park. The clear tips of their seem to disappear at a distance, but the dark patches near the abdomen are visible, so I sometimes mistake them for a large black fly until I get closer.

Pollinating and Nectaring Bees

Of course, bees forage busily along the path as well. Dr. Gary Parsons, from the Entomology Department at Michigan State University, identified this little native bee nuzzling a Rough-Fruited Cinquefoil blossom (Potentilla recta) as a female Leafcutter Bee (genus Megachile.) The clue he gave me is that a leafcutter has stiff hairs (scopa) covering the underside of its abdomen and that’s where it carries its pollen. In the photo on the right, the one flying away with its bright yellow underside was evidently a dead giveaway.

Paul snapped a fine shot of one of our native Bumblebees (genus Bombus), oblivious of a Bull Thistle’s (Cirsium vulgare) thorns below as it gathers nectar from the blossom.

A native bumblebee feeding on nectar from a Bull Thistle blossom. Photo by Paul Birtwhistle

Colorful Long-legged Flies

Along with the butterflies, dragonflies and an occasional damselfly (more about them later), an assortment of metallic flies dotted the leaves along the trail, but not your plain old black house flies! Dr. Gary Parsons tells me that they are from the family Dolichopodidae, also known as Long-legged flies. These common tiny insects perch in bright sunlight waiting for smaller, unsuspecting insects to cruise by. I like their diminutive size, the way they stand so elegantly on those long legs – and they come in an assortment of colors as you’ll see below!

The Plants that Feed and Shelter Them All

Now of course, what sustains all these creatures are the native plants that serve as host plants for their offspring, i.e., larvae/caterpillars. Here a Common Pug caterpillar (Eupithecia miserulata) is foraging on the petals of a Black-eyed Susan (Rudbeckia hirta). Dr. Parsons reminded me that petals are actually just modified leaves so caterpillars can feed on them, but since they disappear quickly, leaves are the staple of a caterpillar’s diet.

A Common Pug caterpillar foraging on a Black-eyed Susan blossom

The beauty of native plants is that they can be both decorative and productive, providing lots of sustenance for the insects that are an essential ingredient of the entire food web. So here’s is just a sampling of the myriad of native wildflowers and grasses along the meadow trail.

The Forest Trail Above the Ravine: Damselflies, Abundant Moths and One Useful but Really Ugly Fly

The dappled forest above Stony Creek Ravine

Under the Forest Canopy, Beauties and the Beast

The forest at Stony Creek Ravine Park is a different world when it comes to insects. At the edge, where the forest meets the sunshine, butterflies seem to dominate. Both of the ones I saw imitate the dappled light of the forest with brown wings marked with white spots in lovely patterns. The Little Wood Satyr (Megisto cymela) is the smaller of the two. Notice how the design on the underside of the wings is a bit more complex. Some sources suggest that the eyespots distract predators from attacking vital body parts. Butterflies can survive with ragged wing edges but an attack on the head is instantly fatal. I thought perhaps the larger spots on these forest edge species also provide more camouflage when the butterfly lands in dappled light. No one seems to be sure exactly how their patterns function.

The larger Northern Pearly-eye (Enodia anthedon) spends more time in the woods itself, especially near moist areas. It feeds on tree sap, rotting fruit, fungi and even dung – not a picky eater, evidently, eh? You’ll often see its head slanted downward on a tree trunk. Quite the set of spectacles on those buggy eyes and the orange and black antennae are very fancy!

The Northern Pearly-eye in its characteristic upside down position

Deeper in the shade of the forest, though, tiny moths flourish. The oaks in our forests and lawns act as host plants for the largest variety of insect caterpillars of any tree in North America, according to Dr. Doug Tallamy, a professor of entomology and author of The Nature of Oaks. Some moth larvae pupate on the tree, some burrow into the soil below but many just pupate within the leaf litter and then emerge in warm weather. So as I walked down through the woods at Stony Creek Ravine, huge clouds of tiny, triangular, leaf litter moths floated up at my feet. Almost every one immediately scuttled back under the leaves. But a gray one, that I believe is a Speckled Renia moth (Renia adspergillus), paused on a patch of bright green moss. So exciting for me see one as more than a flutter at my feet!

This Speckled Renia moth landed briefly on the edge of bright green moss before scooting back under the leaf litter!

Actually that short pause may not have been a good move for the Speckled Renia. Nearby, I saw the “not-so-bad” but “very ugly” insect of the blog title. Robber Flies (family Asilidae) are aggressive predators, and like the “bad guys” for whom they are named, they generally ambush other insects, including their own kind, from a hiding place. I saw two different insects meet their demise in the grip of a Robber Fly.

Robber flies don’t bother humans unless you’re handling one; I’d avoid that unless you’re doing research. And they are simply providing the service predators provide: keeping the numbers of their prey at a balanced level within their habitat. If you see one in your garden, ignore it; it will probably eliminate many pests for you. At a wetland, I met one up close and personal and really, that is one ugly bug!

The bristles on the head of the Robber Fly protect its face when its wrestling with its larger, struggling prey like bees, grasshoppers or dragonflies!

Deeper in the forest, I watched a black and white blur move toward a log. As I stepped forward, it suddenly transformed into just a fleck of something lying on a log. I thought perhaps my eyes had deceived me and it was just a bit of falling detritus. But I decided to ask Dr. Parsons if I’d really seen a living, moving creature. On the left below is the pointy fleck I saw, on the right the closeup I sent to Dr. Parsons.

Dr. Parsons let me know I wasn’t crazy. The tiny moth’s larvae is part of a large insect family, the Tortricidae, commonly known as Leaf Rollers. The caterpillars in this family eat and pupate in a carefully rolled leaf, hence the name. Dr. Parsons surmises that the adult moth above is most likely a Banded Olethreutes (Olethreutes fasciatana). Many members of this family specialize in fruit trees and their caterpillars are considered pests. This one’s offspring feeds on Wild Black Cherry (Prunus serotina), but they’re not considered particularly harmful. Some experts think this camouflage is an attempt to simulate an unpalatable bird dropping. If I hadn’t seen this tiny moth moving, I’d never have noticed it, so I guess the trick works!

Dancing Damselflies Seek the Spotlight in the Creek

But enough of Robber flies and bird droppings! Let’s move on down to the West Branch of Stony Creek itself to enjoy instead the mating ceremonies of elegant Damselflies!

Stony Creek in late June flowing slowly around rocks and under sticks in late June.

I paused near a wooded wetland to witness what appeared to be a pair of damselflies courting. The male Ebony Jewelwing (Calopteryx maculata) landed first and fluttered about from twig to twig, keeping his iridescent colors flashing in the sun. The elegant brown female appeared and began what looked very much like flirting, flying close to him, then landing farther away with her abdomen cocked at an angle. Perhaps she was ready to mate, but the male hesitated. According to Robert DuBois, author of Damselflies of Minnesota, Wisconsin & Michigan, he may have had good reason; females can mate 4 or 5 times each day, rarely with the same male! Anyway, I gave them some privacy and headed toward the creek to see how other males were faring.

In late June, Stony Creek meandered its way around the rocks and sticks protruding from the slowly moving water. A group of Ebony Jewelwing males held a competition there for the sunniest spot on a prominent stick in the creek while waiting for females to show up. One male posed on the stick and began to display. Displays of his impressive wings can be intended to ward off competitors and may also interest females in the surrounding greenery. Periodically, he launched gracefully off his stick and zipped off to confront other males trying to oust him from the spotlight. A series of a scrambles with a group of competitors ensued for about 10 minutes. The University of Wisconsin Field Station’s “Bug Lady,” says that male Jewelwings compete by bumping into each other until one flies off. That’s certainly what occurred at Stony Creek Ravine as the originally male settled back on his stick after each skirmish.

If the male is successful, he’ll grab onto the female’s abdomen with his pincers and the two of them, locked together, will fly to a nearby perch. If she is ready to participate, she bends her abdomen upward and the partners form a heart-shaped “mating wheel.” Benoit Renaud, a generous photographer at iNaturalist.org got a wonderful photo of two doing just that! Thank you, Benoit!

Ebony Jewelwing damselflies in a heart-shaped mating wheel. Photo by Benoit Renaud (CC BY)

After mating, the male releases her and together they fly off to find rushes, sedges, moss or floating plant material. The female then bends her abdomen downward, slits a hole in the plant with her sharp ovipositor and lays her eggs. The male stands guard to protect her from males who might try to abscond with her and remove his sperm before she lays the eggs. Evidently, despite that heart-shaped wheel, damselfly mating is not a particularly romantic process. But it’s kept these graceful insects on the wing for thousands of years, so we won’t argue with it, right?

A week or so after I took my damselfly photos, the July deluge poured down on us. The once placid creek rushed through the ravine, flowing over the rocks and sticks in the damselflies’ courting arena. According to the “Bug Lady,” the Ebony Jewelwings like plants in a “moderate current” in which to lay their eggs. So I’m assuming there was a bit of a hiatus in their mating ceremonies this year!

After a series of heavy rains, Stony Creek rushed over rocks and sticks in a sparkling flood.

And Then The Fireflies Arrived…

A firefly beetle in India. Photo by Ashwin Viswanathan (CC BY) at inaturalist.org

I learned this week that fireflies sparkle at twilight in moderate or tropical zones all over the world. I love knowing that. Imagine! As the earth spins away from the sun each day, these tiny Firefly beetles (family Lampyridae) dance across landscapes, delighting humans around the globe!

The males of our local beetle, the Common Eastern Firefly (Photinus pyralis) dance in a “J” formation, flashing their signal as they swing upward. A chemical reaction in the cells at the tips of their abdomens creates the bioluminescence that delights us. And with luck, a female in the area sends a coded signal back in just 1-2 seconds and they find each other.

The incredible variety of insects around (and often in) our home serves many purposes. The possum near our shed eats all the ticks it can find each summer. Bats, birds, and even the ugly Robber Flies, gobble up mosquitos by the millions. Bees pollinate our garden, wildflowers and nearby farmers’ crops. The beating wings of thousands of flying insects lure migrators back to our yard each spring. Here are a few of the most interesting ones we saw just this week.

Recognizing all the services that insects provide, I avoid wide-spectrum “bug killers” and instead try to utilize long sleeves, high socks and strategically applied Deet or Permethrin to repel them when outside. Despite all of that, like you, I swat flies and mosquitoes, flick insects off exposed skin and get snarky when insects slips inside the house.

But then at our darkened windows on these steamy, rain-soaked evenings, I pause to enjoy the tiny fireworks of a glowing beetle dancing in the tall grass at the edge of the field. And I’m lifted out of my grousing about bugs and rainy weather. Night after sticky night, the flash of the firefly reminds me that some insects are magical and that all of them play a crucial role in keeping life humming on this gorgeous little planet.

2 thoughts on “Stony Creek Ravine: Insects! The Good, the Not-all-Bad, and the Really Ugly

  1. Love reading these Cam! I wish I had more insects. Seems like every year I see fewer!

    Do you know why they mowed a section of the wet prairie? I looked at the area they left intact in the middle of it all but can’t see anything unusual. A lot of poison ivy! It amazes me how PI has adapted to surviving in full sun under a grassy cover! I have some in my field as well. Never saw PI on the property when I was a kid! Now I have that as well as bittersweet, which is really difficult to fight!

    Coffee soon?

    Colleen

    ________________________________

    • Hi Colleen – we mowed down some small areas at the wet prairie where big bluestem and Canada goldenrod have become abundant after shrub clearing in the last several years. This should help set back these aggressive plants while we work to establish more plant diversity through seed addition.

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