October is autumn’s transition month. Some days are warm and sunny, creating almost an illusion of late summer or early September. And on those days, a few bees and butterflies flutter across my path, caterpillars bump along through the grass and native wildflowers still bloom in the fields. A turtle in the Draper marsh basks in the thinning light.
Change is in the air. Let’s look back to see what October had to offer as we take the first cold, rainy steps into the austerity of November.
Early October: Late Season Wildflowers Host the Occasional Bee or Butterfly
One Sunday afternoon in October, a Common Buckeye butterfly (Junonia coenia) fluttered down onto the trail right in front of my husband and I. In the summer, Draper Twin Lake Park hosts a rainbow of butterflies. Some mate, lay their eggs and expire, leaving caterpillars behind in their chrysalises. But this colorful little butterfly migrates south for the winter and returns in the spring. Perhaps it stopped at Draper to sample the various goldenrods, since it prefers yellow flowers. Can you see the slightly bug-eyed expression on its face? I laughed to think it was as surprised to see my husband and I as we were to see it land right in front of us!
Late October: Swaying, Russet Prairie Plants Provide a Fall Feast for Wildlife
The video above may look like a sea of dry brown stems to you. But to the birds, particularly the American Goldfinches (Spinus tristis), it looks like your heavily laden Thanksgiving table. In just the video’s 40 seconds, you are seeing hundreds of thousands of seeds: Indian Grass, Coneflowers, Black-eyed Susans, Stiff Goldenrod, Little Bluestem and many more. On the August birdwalk, we spent a happy ten minutes or so watching a flock of goldfinches swaying on bobbing stalks as they stuffed themselves with Stiff Goldenrod seed (Solidago rigida). First there were two and then suddenly there were five all scrabbling to feed on the abundant seed heads.
Relishing Autumn’s Transformation
The Draper prairie with its great looping trail really may look dry, brown and lifeless to some hikers. But not to me. At this time of year, I feel a lot like Ratty, a “country gentleman” sort of muskrat in the children’s classic Wind in the Willows, by Kenneth Grahame, a book I quoted in an earlier blog. Like me, Ratty senses the restlessness of autumn. He heads out into a farmer’s field, much as I waded out into the tall grass of Draper’s northern prairie: “…he thrust into the great realm of wheat, yellow, wavy, and murmurous, full of quiet motion and small whisperings. Here he often loved to wander through the forest of stiff strong stalks that carried their own golden sky away over his head — a sky that was always dancing, shimmering, softly talking; or swaying strongly to the passing wnd and recovering itself with a toss and a merry laugh. Here, too, he had many small friends, a society complete in itself…”
Ratty is a kindred spirit. Autumn also plunges me into the bending and tossing grasses and the whispering of dry stems where I can stand shoulder deep in the prairie and just “be” with it all. Like him, I sense a community of other creatures in the flocks of fidgety birds, the agitated butterflies searching for the last bloom, the relentless plodding of a caterpillar through the grass stems. Autumn’s restlessness urges me to celebrate the change, change and change again of every season. I appreciate that reminder.
Stony Creek Ravine Nature Park is a small park with big contrasts – between the sunlit, gently rolling meadow and the forest with large trees grasping the steep slope that plunges down to the creek stippled with sunlight below. It’s a fairly short walk, just in and out, for now. Eventually, we hope this elbow of a park will be joined to 208 spectacular acres to the east, now being acquired by our Parks & Recreation Commission. So I’d suggest you see it soon, so you can say you “knew it when!”
An Undulating Path through a Meadow of Fluttering Wings
The trail begins in a grove of trees at the end of Knob Creek Drive with its single parking space. A few years ago, Stewardship Manager Dr. Ben VanderWeide removed walls of invasive shrubs that crowded the edges of the trail into the park, obscuring the meadow. Now when I step into the park, the landscape is open to fields filled with tall flowers and sunlight. The meadow is an exuberant, dense tangle of native and non-native wildflowers – and a lot of thistle! But the butterflies and bees make do with what they find and they are everywhere! So I periodically ventured out as far as possible into the shoulder-high plants to get a little closer!
Ben had reported seeing lots of GiantSwallowtails (Papilio cresphontes) on thistles at the park. Having seen them there in previous years, I was excited to look for them. But after a very hot week, they had evidently moved on to greener pastures. I only saw one at an unreachable distance across the meadow on my first visit. But since I saw many of them later at Charles Ilsley Park, here’s a photo of one to refresh your memory. Pretty impressive size, eh? They are actually the largest butterfly in North America!
My birding friend, Bob Bonin, also saw something at Stony Creek in August that I only saw from a distance. I had a quick glimpse of a Snowberry Clearwing Moth (Hemaris diffinis) but couldn’t wade fast enough into the greenery to catch a shot of it. Bob generously shared his beautiful shot of one feeding on the last drops of nectar from a native Bee Balm (Monarda fistulosa). Clearwings lose some of the wing scales due to their hummingbird-style, hovering flight, leaving areas of their wings almost transparent. The yellow and black fuzziness of the Snowberry Clearwing (Snowberry is one of its host plants) means that it’s often mistaken for a bumblebee – perhaps providing some protection from predators.
Native bee-balm also prompted a stopover by the Silver-spottedSkipper (Epargyreus clarus) which, according to Wikipedia, prefers to hang from the underside of leaves at night or on hot and humid days. Bee-balm, true to its name, attracts many native insects, including the ubiquitous native Bumblebees (genus Bombus). (Click on photos to enlarge; hover cursor for captions.)
For the first time ever, I noticed European Honeybees (Apis mellifera) literally running around the tops of non-native Queen Anne’s Lace. I’d never before noticed this “busy bee” activity! They rush across each lacy blossom, perhaps quickly gathering nectar or pollen. Bee Culture, a beekeeping magazine, says that Queen Anne’s Lace produces the greatest amount of nectar in hot weather, so perhaps that’s what attracted them. Let me know in the comments if you have more info than I could find on this phenomenon. Here’s my amateur video of the bee race at Stony Creek Ravine.
It’s always heartening to see Monarch Butterflies (Danaus plexippus) in our parks, especially a female one sipping on Common Milkweed (Asclepias syriaca), its favorite host plant on which to lay eggs!
The Eastern Tiger Swallowtail (Papilio glaucus) is a generalist who can live in lots of habitats, from forests to meadows to urban areas. Its caterpillar can eat and grow on many of the trees in our parks, including Wild Black Cherry, Willows, Cottonwoods and Tulip Trees (see below!), but also on non-native plants like Lilacs. This adaptability means it’s thriving, and that made me glad as it paused so delicately to sip from the only tender part of a Plumeless Thistle (Carduus acanthoides).
A Great Spangled Fritillary (Speyeria cybele) looked a bit ragged and uncomfortable one humid afternoon. I wonder if it had landed on too many prickly, bristly plants like the Plumeless Thistle! Most of the “spangles” are on the underside of the hindwings, so I’ve included an older photo to show them, since this butterfly clearly had no attention of feeding with its wings up.
A Red-spotted Purple (Limenitis arthemis) paused on non-native Queen Anne’s Lace (Daucus carota). It prefers rotted fruit or even dung and carrion, but occasionally it sips nectar from small white flowers like these, according to the citizen science website, butterfliesandmoths.org. These butterflies sometimes produce two broods. The first caterpillars hatch and once half-grown, form a “hibernaculum,” an over-wintering refuge which for caterpillars usually involves a folded leaf and some spun silk to secure it. They then emerge in the spring and finish maturing. According to Wikipedia, some of the first larvae “are able to mature during the summer, so they emerge as the second brood [in] early fall,” but may have a tough time surviving winter cold. The prime condition of the butterfly below makes me wonder if it was from an early second hatch.
Some small butterflies also made the most of the late summer meadow. The common and colorful Pearl Crescent (Phyciodes tharos) landed repeatedly on the path in front of me, as they often do. These very small butterflies can mate many times between April and November so we’re almost bound to see one on any summer walk in our parks. And we’re also likely to see the non-native Cabbage Butterfly (Pieris rapae). I just love the sculptural look of the ventral (underside) of the wings on the one below. I think she’s a female since I can just make out the double wing spots on the dorsal (upper side); males have only one spot.
Right now, you’ll probably see a creature along the trail that looks like a butterfly with its black wings edged in beige, but is really the Carolina Locust (Dissosteira carolina). Despite seeing them every summer, I’ve never gotten a shot of their sudden flights from under my feet. So I can only show you what they look like once they land. But I’ve borrowed with permission a photo from an iNaturalist.org photographer, Joshua G. Smith, who held one in his hand to get a photo of the wing.
The Woods, the Deer Effect and a Bubbling Creek Below
The woods at Stony Creek Ravine Nature Park is full of big oaks and some beautiful native Tulip Trees (Lirodendron tulipfera)! These are not the shorter, heavy flowering cultivated trees that I grew up seeing in people’s yards. These mighty trees grow beautifully straight and tall often with few limbs once they reach 80-100 feet. In virgin habitat, they can grow to 160 feet and their girth can be as wide as 10 feet! According to Ben, there’s a huge one on the new piece of property that is planned to eventually connect with the existing 60 acre park. I hope someday I’ll be able to see it and show it to you here!
Wild tulip trees (vs. nursery cultivated ones) only bloom at the top of the tree, so their glamorous flowers are rarely seen, but are rich with nectar. Their bark is ridged in an orderly pattern. The leaves have a unique, squared-off shape. And the graceful, seed-filled cones stay on the tree all winter only falling to the forest floor in the spring. I have never seen the flowers up close or the cones, so my thanks go to iNaturalist.org photographers kwilie and Sandy Wolkenberg for sharing the bloom and cone photos below. We’re lucky to see Tulip trees here because we are at the far north edge of their range. Can you tell I’ve found a new favorite native tree?
The forest floor beneath the impressive trees, though, is almost barren. The shade of course is very dense. But a huge problem is that, despite a limited hunting season in this park two days each week in from October to January, the deer are plentiful. As a result, few woodland plants reach maturity on the forest floor. Deer have no front teeth, so the stems left on the plants they graze are ripped and flattened as seen below. Rabbits, for instance, with their incisors, make a neat, angular cut. But hope springs eternal! Though most tulip tree seeds don’t survive, I found a small sapling that somehow had escaped the notice of the deer -so far.
As you hike down to the creek, more grasses appear. The creek’s moisture encourages some flowers, especially in the spring when the trees haven’t leafed out and more sunlight reaches the forest floor. In summer, the moist river bank is a hangout for damselflies. One warm, gray afternoon, I saw a female Ebony Jewel Wing (Calopteryx maculata) looking at me head-on from a fallen branch.
Her mate is a bit more glamorous, but I also like the elegant understatement of the female.
The west branch of Stony Creek burbles along, tumbling over rocks, slipping under fallen trees, catching glints of sunlight on its surface. And beneath the surface, small fish school in the shallows.
Deep in the woods on the far side of the creek, the shriek of a young Red-tailed Hawk begging to be fed grated upon my ears. Young hawks can repeat this harsh cry for 4 to 6 weeks! I know what adult hawks are dealing with, because in some years, a young hawk subjects my husband and I to their cries from the field next to our house! But hawks believe in tough love and eventually it gets hungry enough, I guess, to do its own hunting. Here’s my recording at Stony Creek Ravine Nature Park.
The youngster was nowhere in sight, but here’s a photo of one taken along Predmore Road near Lost Lake Park in 2017.
On a later visit, I was startled by a flash of huge wings, as a young hawk (I think!) flashed across the path in front of me and stumbled into a tree much too small for its size and weight. It wobbled back and forth on a thin branch for a few seconds. But before I raised my camera, it lumbered up into the air and soared off into the woods on the far side of the meadow. As far as I could tell this “desperate escape” was caused by the harassing pursuit of a single Blue Jay (Cyanocitta cristata) – hardly the behavior of an adult hawk! Like a lot of adolescents, this young bird just needs a bit more time to grow up.
Back Up in the Meadow – Baby Birds and a Fun Baby Insect
It’s a steep climb out of the ravine, up through the woods to the path and the sunlit meadow. Back on the trail, I noticed out in the meadow a few fledglings learning to make their own way in the world. A juvenile Eastern Bluebird (Sialia sialis) still sported the fledgling’s dappled chest, a field mark common to other members of the thrush family. It had landed high on the bare branch of a snag to survey the field, looking quite confident that it could survive on its own.
A little Song Sparrow (Melospiza melodia) popped up out of the greenery, looking like a plush toy! Donald W. Stokes’ Guide to Bird Behavior (Vol. 1) points out that a good field mark for juveniles is that their tails are about half the size of an adult Song Sparrow. Next spring, this little sparrow will look for a nesting site within its “song neighborhood,” i.e. close to the the place where adult birds sing the songs that it heard and memorized as a nestling. According to this Cornell Ornithology Bird Academy website, juvenile male sparrows need to practice for several months before they can sing their repertoire perfectly – sort of like babies babbling before talking.
Far out in the meadow, I saw a hard-working male American Goldfinch (Spinus tristis) traveling about with a juvenile. Male Goldfinches do most of the fledgling feeding because the females are busy with a second clutch of eggs. Goldfinches wait to breed until mid-summer when thistles provide them with fluffy pappus (downy plant material) to make an almost water-tight nest lining. Then they feed their young with partially digested thistle seed. I could hear an insistent fledgling calling to be fed and could see the adult male flying to meet it. Each time, the two of them disappeared into the greenery for a meal. I moved further into the dense undergrowth, trying to see the adult feeding the youngster. Finally, the fledgling, alone again, came out onto a bare tree stem and diligently chewed at its tip. My best guess is that this behavior is a way to practice stripping hulls from the seeds that make up almost all of a goldfinch’s diet. But I’m not sure, though I’ve seen two young goldfinches do this in the last week!
Out in the field, the adult male Goldfinch hopped about on a thistle, filling his beak with seed to share with the youngster. I believe the thistle he chose is again Plumeless Thistle. At least it appears to feed the birds and butterflies!
The birds will be able to enjoy a treat before too long, because a big, energetic patch of American Pokeweed (Phytolacca americana) with its Dr. Seuss-style color scheme has appeared along the trail! The green berries in the photo below will gradually turn white and then deep purplish-black. When ripe, they are much beloved by birds, particularly the Gray Catbird, Brown Thrasher, Northern Cardinal and the Northern Mockingbird, according to Wikipedia. However, they are highly toxic to most mammals, including us humans! So admire them, but no snacking, not even one!
On the way back to the car, I spotted one of the largest and most graceful nests of EasternTent Caterpillars (Malacosoma americanum) I’ve ever seen. These gregarious caterpillars head out each morning to forage together and return to their tents at night. The tents are added to each day before they leave, so they have multiple layers. As a result, the caterpillars can go to different parts of the tent for heating or cooling. Though their feeding can defoliate trees, they cause little permanent damage and the trees generally re-leaf once they’re gone.
My forays deeper into the meadow left me with socks covered in burs and sticky seeds. So on my way back to the car, I stopped at the beautiful bench commemorating the Kezlarian’s generosity toward this park. Along with the burs, I plucked a small caterpillar from one sock and set it on the bench. To my delight, it quickly began scooting around on the granite at a rapid pace. I laughed out loud! It was an inchworm! I looked them up when I got home and discovered they are caterpillars of the large and diverse moth family, Geometridae. Here’s the 30 second video I took of it that still tickles me. (It should have some cartoon music in the background, but again, I’m a complete beginner at videography!)
By the way, after filming, I let it climb on a dry leaf, carried it to a nice green one and wished it well.
The Persistence of Nature as a Challenge to Care
Places like Stony Creek Ravine Nature Park strengthen my hope when life feels challenging. The intense July heat – reportedly the hottest July in history worldwide! – finished the bloom of many flowers that might have lasted longer in a normal year. But honey bees rush about on less nectar-rich blooms, trying to gather their much-needed supply of pollen to feed the young or the nectar for making honey to feed the over-wintering colony. Some butterflies make their way across great distances in unpredictable weather, seeking out available nectar to feed themselves and suitable host plants for their eggs. Young birds exercise their new skills, learning within weeks how to forage on their own in a landscape shaped by the changing climate. The glimmering creek down in the shadows of the forest rises and falls with the rainfall, but, for now, flows on.
This same persistence, I think, also challenges us to do what we can to cool our planet and return to the patterns that nature has bequeathed to us through eons of experimentation. We owe it to the wildflowers, bees, butterflies – all of the natural world that supports us – to shape our lives not just to our human needs, but the needs of all the living beings that share this little blue planet with us. The township stewardship program is working on that, I’m working on that – and I bet you are, too. Let’s press on!
When most of us think of pollinators, the EuropeanHoney Bee (Apis mellifera) comes to mind first – and with good reason. These hive bees work industriously in agricultural fields and orchards. And we benefit from the fruits, vegetables and of course flowers they visit. According to MSU Extension, though, they are active in temperatures above 60 °F and prefer clear, sunny, placid weather. In case you haven’t noticed (or don’t live in Michigan), that’s not yet our weather here this year.
Luckily, native bees and hoverflies come to our rescue, and the rescue of countless wildflowers. Bumblebees (genus Bombus), our chunky native bees, only require temperatures above 50° and will fly in wet, dark and windy weather – the kind we’re living with this year! And along side them are other native bees and the ever-present hoverflies who look like bees but aren’t. So let’s see who’s out and about in our parks pollinating plants on these cool, damp days of early summer.
[A Disclaimer: I’m a learner when it comes to insect identification, but I’ve done my best to figure out what I’m seeing. Let me know in comments if you think I’ve erred. And if you’d like more detailed info, check out my two main sources: a fine book by Heather Holm entitled Pollinators of Native Plants and this excellent web article by Jason Gibbs from MSU Dept. of Etymology.]
Native Bees Happily Take on the Job of Spring Pollination
Female bees of all species carry most of the load when it comes to pollination, because they feed pollen to themselves and their young. Some species stash it on hairs or in pollen baskets on their hind legs. Others let it spread thickly across the stiff hairs of their abdomen. Wasps, like Yellow Jackets or Hornets, can look like bees but they don’t collect or eat pollen. (They are predators who keep insect numbers in check, including some garden pests.) So if you see lots of yellow or orange pollen on the leg or abdomen of an insect, it’s a bee! Where are these bees finding pollen now?
Native Wild Lupine (Lupine perennis) rises elegantly within the restored prairie at Charles Ilsley Park in early June. Look for them near the observation deck at Gallagher Creek Park as well. They are a popular stop on the pollen route for our native bees right now.
A Metallic Green Sweat Bee (genus Agapostemon) found the Lupine blossoms irresistible. These very small bees are solitary; they don’t live in hives. Instead, they make tunnels in bare soil and tend their young alone. Sweat bees are occasionally attracted to human sweat on hot, dry days but their sting is not as severe as a bee or wasp. They are normally docile while foraging but can be aggressive if you get near their nests. But please don’t use pesticides on them. These little bees do a lot of pollinating! Creating a spot of bare soil on your property away from your garden and house where they can nest will make both you and them feel safer.
One cool afternoon, I watched a couple of sweat bees make the proverbial “beeline” for the native Daisy Fleabane (Erigeron annuus), a close relative of asters and daisies, but a different genus. These tiny, sun-faced flowers are one of the first blooms to emerge in spring and they last all summer. So it seems that the two sweat bees heading in from the right on the photo below know a reliable source of nectar and pollen when they see one!
A native Bumblebee (genus Bombus) used its long tongue to reach inside the lavender lips of the Lupine blossoms at Gallagher Creek Park and then flew off with its pollen load tucked neatly into the pollen sacks on its legs. According to author Heather Holm, bumblebees sometimes use a technique called “buzz pollination” in which they release pollen from tight places by clinging onto a plant’s anthers (the tip of the male stamen that holds the pollen) and activating their flight muscles, making a buzz. Poof! Out comes the pollen. Neat trick. (Click on photos to enlarge; hover cursor for captions.)
Carpenter Bees (genus Xylocopa) shape their nests by patiently shaving off wood bit by bit to make perfectly round holes, usually on the underside of branches, or at our house, under deck railings! They lay their eggs inside, sealing each egg in separately with neat plugs of pollen to keep the young larvae fed. Later, the young bees will overwinter in these nests to emerge for mating the following spring. Here’s what I’m quite sure is an Eastern Carpenter Bee (Xylocopa virginica) nuzzling a Blackberry blossom (Rubus allegheniensis). It looks a lot like a native Bumblebee, but its abdomen is shiny black instead of fuzzy and it has a dot in the center of its yellow thorax.
The blackberry bush also hosted another bee. I believe it’s a Masked/Cellophane Bee (genus Hylaeus). These solitary bees are the only ones that transport pollen in a crop like some birds do with seed. These bees use exisiting cavities in wood for nesting, and wrap their larvae in a thin membrane that evidently gave them the name “cellophane bees” – and they also have white patches on their heads, hence the “masked” name.
Native Golden Alexanders (Zizia aurea), an early summer flower, attracted the attention of another native pollinator, the solitary Leafcutter Bee (genus Megachilidae). They can be very active within blossoms, making what some sources describe as a “swimming motion.” Evidently, that also releases a lot of pollen that they carry on stiff hairs on their abdomen. Their nests are built vertically in hollow plant stems or other natural cavities. They neatly cut and then chew bits of leaves to line each cell. Entomologists suppose that the leaves may preserve the moisture in the pollen plug at the end of each cell, so it will last until the larvae hatches to eat it. The larvae then pupates, emerges for a short life of a few weeks and starts the cycle again.
And then there are the “Wannabees”
I love Jason Gibb’s term “wannabees” for the ubiquitous Hoverflies – also called flower flies – members of the genus Taxomerus (family Syrphidae). Hoverflies visit flowers frequently and are commonly mistaken for bees. Many of them mimic bees and wasps, being patterned in white, black and yellow (or orange). But they differ from bees in one important way; hoverflies do not have stingers. They just want their predators to think they do! They feed on both pollen and nectar. Though hoverflies don’t carry as much pollen on their smooth bodies as bees do on their fuzzy ones, they may make up for that by visiting flowers more often. As a result, they are considered the second most effective plant pollinators. Another great benefit of hoverflies is that their larvae eat aphids like crazy, much like ladybugs do. So they can keep plants healthy as well as do some pollinating.
Drama Unfolds on Daisy Fleabanes!
It’s not a surprise that the nodding stalks of Daisy Fleabane (Erigeron annuus) show up in every field in the spring. Hoverflies move constantly from one to the next since not many different wildflowers bloom in this cold spring! As they land, of course, they drop pollen on the waiting stigmas of the flower, just what’s needed to produce more Daisy Fleabane. From my observation, the flowers in bright sunlight get more attention from hoverflies than those in the shade. Perhaps they see in ultraviolet like bees and the flowers look much more inviting in the sunshine?
But more than just pollination is taking place on those sunny little blooms! It turns out that a Daisy Fleabane can be a stage for high drama – birth and death among the petals! One tiny fleabane flower featured the mating of two hoverflies while a third ignored them in its avid search for a good meal. The dispassionate female seems to be casually having a snack as well.
And on another Fleabane blossom, an ambush! I’ve just learned about Crab Spiders (genus Thomisidae). These crafty arachnids don’t spin webs. They simply sit on or just under the edges of flowers waiting to grab unwary insects. Those long curved front legs do look a bit crab-like!
The Bluebottle Fly (genus Calliphora) in the photo below seems to have been oblivious to a crab spider until it was grabbed around the middle by one of the long legs of its hidden predator. Those big fly eyes look vaguely shocked, don’t they? The hoverfly on the blossom above seems unconcerned, its head deep in the pollen. And what I think is the green sweatbee flying in may choose to do the same on a different bloom. I doubt they stayed around long enough to be a second and third meal for the spider!
What about the Butterflies?
Well, butterflies are arriving, or hatching or coming out from under bark after overwintering. But not many are present yet. And let’s face it; the flowers available now are not especially tempting when compared to the variety and plentitude of summer. So the butterflies that appear in the parks make do with other food sources – sweet tree sap, rotting fruits from last fall, carrion, even occasionally the nutrition left in animal scat! Here’s a selection of the butterflies I’ve seen so far and not one of them was pollinating a flower! (Click on photos to enlarge; use pause button for captions.)
I’ve also seen three different Monarchs but they didn’t stop to have photos taken. And the very tiny White-striped Black moth (Trichodezia albovittata) is a first sighting ever for me. Its miniscule black and white wings flutter so fast that when flying, it looks like a blurry signal of dots and dashes! I was so happy when it paused for a few moments!
You’ve probably noticed that I’ve used the word “larvae” several times in this piece. The common term for these squiggly young is “caterpillar.” Caterpillars (as I’ve mentioned before) are the preferred food that birds stuff down the tender throats of their hatchlings. They are great baby food for birds, full of protein and fat and easy to swallow.
So let’s be glad that our native insects are out gathering pollen for two reasons. Our bees and wannabees keep the wildflowers (and eventually fruits and vegetables) reproducing year after year. But by also feeding pollen to all those larval bees and flies, they feed the young of clever birds who winkle them out of holes and pluck them off of leaves and limbs. Yes, we may get a few cut, chewed or even defoliated leaves in our garden. But many of those caterpillars will nourish the next generation of glorious birds singing the morning chorus! Now doesn’t that make you appreciate insects just a wee bit more?
During this cold week, when nature seemed pretty hunkered down – and I sure was! – I decided to explore how our local bugs get through the winter. I’d always thought of insects as killed off by the cold – and many are – but others are biding their time and getting through the winter in surprising ways – like the bark beetle larvae which left their filigree in the fallen tree above.
A Chickadee’s Home for the Night?
But I did venture out at dusk to see if I could spot birds settling in for the night. And a couple of Black-Capped Chickadees (Poecile atricapillus) obliged by disappearing into a snag. One let its tail protrude from the hole long enough for me to locate it once it suddenly disappeared!
When I tried lightening this hole on the computer, the little bird appeared to have turned its head straight upward to fit into the hole! If that’s what really happened, I hope it found a more comfortable place to spend the night once I left. Perhaps just getting out of the cold, though, is more important than a stiff neck.
Now, Concerning the Winter Survival Strategies of Insects…
Bernd Heinrich, in his book, Winter World: The Ingenuity of Animal Survival, claims, “…there is no life-form on earth as diverse, varied, tough, and inventive as the insects. ” Heinrich’s adjectives – diverse, tough, and inventive – certainly apply to the varied and creative strategies that our Bear Creek insects employ during the winter months! So now, while walking along the snowy trails, I can imagine all these small creatures swimming under the ice, tunneling beneath the bark, dozing in tree holes or eating inside plant galls, waiting like we all are, for the burgeoning of spring.
Wasps, Hornets, Bees and Ants: Long Live the Queen!
This category of insect winter survival has two sub-strategies. Almost all wasps, hornets and many bees, including our native Bumblebees (genus Bombus), live only one season. After mating in the fall, the only member of the hive that survives is the fertile queen. She leaves the hive and inserts herself into a crevice in a log or under bark – some moist place in which she won’t dry out as easily in the winter. If she survives, she rouses in the spring and goes off to find a new nest location, lays eggs and the hive begins again (click on photos to enlarge or hover over them for captions).
European Honey Bees (Apis mellifera)and Ants (family Formiciadae) have a different strategy – staying in the hive with the queen, and protecting her during the winter. Honey Bees eat honey during the winter and they keep their hive and the queen warm by fanning their wings. They were imported from Europe because this survival strategy meant that Honey Bees dependably provided honey and crop fertilization from the same hive year after year.
Ants lower their metabolism in the winter and pile onto their queen in order to keep her warm. I believe I saw evidence of Carpenter Ants (genus Camponotus) in this tree on the western trail through our Oak/Hickory forest last summer and fall.
Carpenter Ants don’t eat wood like termites; they chew it to make the galleries that connect parts of their nest, and then deposit it outside. Assuming that these were Carpenter Ants, they will have moved deeper into the nest and are now hibernating together with their queen.
When spring warms a bee hive or an ant nest, bees and ants are ready to go, having survived the winter as adult insects.
Green Darners: Migration
A very small number of insects migrate much as birds do. Those of you who read the blog this summer will remember that some of the Green Darners (Anax junius) head south in the winter.
According to National Geographic, these large dragonflies build up fat reserves and as cold weather sets in, some of them ride south on a north wind. Like avian migrants, they make stopovers to rest and feed along the way and, strangely, follow the same flight paths as birds (don’t they worry about being eaten?). But unlike birds, it’s a one-way ticket for these Green Darners. They breed in the south and die and it’s their offspring that arrive the following spring. Some Green Darners and many other dragonflies, though, use the following strategy.
Damselflies and Most Dragonflies: Naiads under the Ice
Naiads appear in Greek mythology and children’s books (like C.S. Lewis’ The Chronicles of Narnia) as glamorous winged water nymphs overseeing streams, rivers, and fountains. The naiads under the ice at Bear Creek, however, are simply the homely immature life stage of the beautiful dragonflies and damselflies we see in the summer. In warm weather, the females lay their eggs on vegetation in the pond or marsh. Drab, wingless naiads with hooked jaws hatch from the eggs. Even in winter, these hungry carnivores are swimming about consuming mosquito larvae and other invertebrates. After molting up to 15 times (some dragonflies take 3 years to finish molting!), they crawl up out of the water onto a plant, bend backwards out of their exoskeleton in one last molt and emerge in the warm sunshine as brightly colored and patterned dragonflies or damselflies like these:
A Quick Overview Before We Go On: The rest of the insects I’m exploring here have a four stage development: 1) Fertile females produce eggs; 2) Larvae , which in butterflies and moths are also called caterpillars, emerge from the eggs and eat like crazy; 3) Pupae form. In butterflies, their bodies harden into their pupal form which is called a chrysalis. Moths and many other insects spin cocoons and go through the pupal stage inside them; 4) Adults emerge from chrysalises or cocoons and mate to start the cycle again. It turns out that different insects spend the winter alive and well – but in different stages of development.
Overwintering as Adult Insects: Mourning Cloak Butterflies
The adult Mourning Cloaks (Nymphalis antiopa) that we see in early spring emerge from bark crevices or trees holes where they hibernated during the winter (those woodpecker holes in snags do a lot of good, don’t they?).
These early spring butterflies hatched the previous summer. They ate a little and then went into summer torpor, which is called “estivating.” In the fall, the adult butterflies became active again, ate to put on weight, and settled into a hole to wait out the winter. In the spring, they emerge very early, sometimes when snow is still on the ground, and mate. And their eggs, larvae and pupae begin the cycle again.
Overwintering as adults gives some butterflies an advantage since in early spring, there is less competition for food (tree sap, decaying matter) and fewer predators, since many birds haven’t yet returned from migration.
Overwintering as Pupae: Spring Azure Butterflies
According to the University of Wisconsin Madison Field Station website, the tiny lavender/blue Spring Azure butterfly (Celastrina ladon) overwinters in the pupal stage that in butterflies is called a chrysalis. When the female emerges in early spring, she mates within hours of hatching, lays her eggs the next day and dies on the third – an extremely short adult life!
Larvae hatch from the eggs and eat for about a month. Each then forms a pupa (called a chrysalis in butterflies) and the Spring Azure stays in that form from early summer until the following spring! A long wait as a pupa for a very short time as adult mating butterfly!
Overwintering as Larvae (commonly called caterpillars): Bark Beetles and Woolly Bears
This overwintering strategy, like the Queen strategy of bees and ants, takes at least a couple of forms – staying under bark or freezing solid!
Bark Beetles: Busy Tunneling Under the Bark
Bark Beetles (family Curculionidae) are tiny insects (about 1/10 of an inch) that can survive the winter as larvae, pupae or adults. They are a major food source for woodpeckers, especially in the winter (so that’s why woodpeckers continuously peck at tree bark!). According to Donald Stokes’ book, Nature in Winter, adult insects bore through the bark to a softer inner layer. The males enlarge a “nuptial chamber” where mating takes place. The females then tunnel out into a branch or the trunk, under the bark, to lay their eggs. The larvae who hatch from the eggs make increasingly larger tunnels as they eat and grow during the winter.
Eventually, they form pupae under the bark from which adults emerge in the spring. The adults bore back through the bark and fly off to another tree. According to Wikipedia, some of these tiny insects become pests and kill trees, especially when climate change and other factors promote their survival. Most, however, tunnel within weak and dying trees or aid in recycling the wood of dead trees.
Woolly Bear Caterpillars: Freezing Solid!
Woolly Bear Caterpillars are the larval stage of the somewhat drab Isabella Tiger Moth(Pyrrharctia isabella). These caterpillars, by the way, don’t predict winter by their bands; they simply molt throughout the summer “becoming less black and more reddish as …winter approaches” (Bernd Heinrich, Winter World).