On FRIDAY, I’ll be talking about how the canyon came to be and why it’s one of the coolest places on the planet. You’ll learn some easy geology and discover, among other things, the tale of my finding the continent’s smallest butterfly in its largest and most spectacular ditch. You’ll also see pretty pictures (unlike that shot of Mr. Dorky up there). More like these:

Autumn’s falling leaves probably show more diversity than snowflakes. So it was odd and puzzling to find matching patterns in poplar leaves one October morning.

This mystery began during a walk through some hardwoods with my buddy Steve Kappel. We were talking about evolution or politics or something when Steve stopped, picked up a quaking aspen leaf (Populus tremuloides) and stared at it for a while without uttering a word. (That’s a classic Steve move.) I kept walking and blathering on about Darwin or Democrats or something.

But I soon reversed course. It is usually noteworthy when Steve stops in the woods.

“What’s with the green patch?” he asked.

Clueless, I pondered the leaf.

“Yeah, what’s with the green patch?”

We looked down to find most of the yellow poplar leaves retaining a patch of green tissue radiating from the basal area of the midrib. Very few had bilateral patches. I collected some leaves and emailed a photo and query to a handful of smart people. Many had theories; none had an explanation. It wasn’t until I put the leaf under a dissecting scope that I found the answer.

Residing in a tiny pocket of tissue near the green patch was a translucent caterpillar not much more than 2 millimeters in length. It was feeding in there; I could see the frass (caterpillar poop). With help from Dave Wagner, the renowned entomologist at the University of Connecticut, our critter turned out to be a moth in the family Nepticulidae, probably Ectoedemia argyropeza or most certainly a member of that genus.

“The really cool thing is that the larva secretes an anti-senescent substance that keeps part of the leaf alive – probably a cytokinin,” Dave wrote in an email. Cytokinins are plant hormones that promote cell division. In this case, it seems, the caterpillar was keeping part of an otherwise dead leaf alive so that it could keep eating.

Another cool thing is that this moth is parthenogenetic; females can produce fertile eggs without help from males, which, as it turns out, are quite rare.

The tiny adult moth flies in spring. Many species in the genus are black and white with orange scales around the head. But don’t expect to find one. Your best bet for discovering this animal is to watch the trail for patterns in poplar leaves this fall.

They swarm at mountain summits, along dirt roads, in back yards and over meadows. Some are migrating; some are mating. But mostly they’re doing what dragonflies do — flying around and killing things. Here’s the scoop on dragonfly swarms.

August is prime time for flights of the large “Mosaic Darners” in the genus Aeshna. “Devil’s Darning Needle” is a colloquial term for these insects. They are the big and marked in pastel blues, greens and yellows. North America has about 16 members of this genus, all of which can be identified by the shape of the two stripes on the thorax. Pictured here is a pair of Variable Darners (Aeshna interrupta) copulating on my front porch; in this species the stripes are broken — or interrupted.

Swarm Foraging
Dragonflies mature from egg to growing larvae in water — rivers, lakes, bogs, marshes, roadside ditches and backyard ponds. Aeshna, most abundant at lakes and ponds, can undergo a mass emergence from their natal waters to fly as adults in big numbers. And if they’re not having sex, dragonflies spend a good portion of their day flying around and killing things. So much of what we’re seeing now amounts to swarm-feeding or swarm-foraging.

Swarms form around prey species, often small flies. On the wing dragonflies patrol, nab a flying insect, dispatch it with a swift bite and most often land somewhere to finish its meal. In these feeding swarms, dragonflies can track and follow aggregations of prey species as they shift in location and abundance. They can even locate food using past experience and topographical clues. One researcher in Costa Rica (Young 1980) noticed Roseate Skimmer (Orthemis ferruginea) gathering in good numbers to feed over trays of black-pepper berries fermenting and drying in the sun. The skimmers were feeding on fruit flies and other insects attracted to the berries. When the trays were removed, the Roseate Skimmers departed post haste. When empty trays were returned to the site, the skimmers returned to investigate, apparently keying on the visual clue as a source for food. Other causes for swarm formation include dragonflies and their prey gathering in the lee of an otherwise windy setting, for example, or in a sun-dappled clearing in the woods where evening light makes prey easier to locate (Corbet 1999).

Migration
August, at least here in the East, is also the month for swarms of an amazing dragonfly called Wandering Glider (Pantala flavescens). About three inches long, Pantala is the color of gold and a flying machine. It is found on every continent except Antarctica. Its long, wide wings allow this dragonfly to cross oceans, making Pantala a champion flier among dragonflies, in many respect the albatross of insects.

It is also steeped in mythology. Pantala, for example, is a symbol of courage and victory in Japan. Large numbers appear in Honshu (the nation’s main island) and Kyushu (the third largest island) around August 15, a date on which Buddhists believe ancestral spirits visit their homes. On August 13, 2009, Pantala flavescens invaded Montpelier, Vermont (where I live and have an office), probably numbering in the thousands. Exactly one year later, on August 13, 2010, they came again. Thousands of these elegant dragonflies swarmed the city. They cruised the intersection of State and Main. They hovered in the parking lot of the Shaw’s grocery store. And they patrolled in front of the Vermont Statehouse. Few people noticed the Wandering Gliders that day, at least until I went downtown with a net and started swinging. Pantala is a champion migrant.

Most adult dragonflies live out their lives at a single site – a pond, a bog, a river – over the course of days, weeks or, rarely, a few months. But some live long and migrate like birds. We see it mostly in the fall. In fact, birders often notice migrating dragonflies from hawkwatch sites. One of my best encounters came while birding on Monhegan Island, off Maine’s midcoast, in September of 2009. It was a river of dragonflies, almost entirely Common Green Darners (Anax junius) heading out to sea, southbound for who knows where. But we’re learning. Researchers are attaching tiny radio transmitters to Anax junius and other migratory dragonfly species in order to track their movements (Wikelski 2006). Others can catch a migrating dragonfly in, say, New Jersey, and by measuring trace concentrations of certain molecules (stable isotopes) in its tissue can learn about where it grew up. It turns out, among dragonflies, you are what you eat. What a dragonfly ate while growing up can give a biologist a clue to where it was born (or hatched in this case) no matter where or when it is caught by a researcher. With tools like these only now are we beginning to learn how far and for what reason dragonflies are migrating. I’ll cover migration in a separate blog post. But here’s a post, video and photos from a Pantala swarm I encountered in Michigan on July 24, 2010.

If you want more, check out The Dragonfly Woman’s blog post on swarms. I heartily recommend this site.  The Dragonfly Woman is tracking swarms around the continent. If you’re seeing a swarm, please report it to me in the comments section of this post.

References

Corbet, P.S. (1999). Dragonflies: Behaviour and ecology of Odonata. Essex, Harley Books, 829p.

Wikelski, M., Moskowitz, D., Adelman, J. S., Cochran, J., Wilcove, D.S., and May, M.L. (2006) Simple rules guide dragonfly migration. Biol. Lett. (2006) 2, 325–329

Young, A.M., (1980). Observations on feeding aggregations of Orthemis ferruginea (Fabricus) in Costa Rica (Anisoptera: Libellulidae). Odonatologica 9:325-328.

OK, it’s not exactly a tongue. Butterflies and moths have a straw-like proboscis that they coil like a watch spring and unfurl to suck nectar from flowers. The primrose moth’s proboscis is about half the length of its body. That anatomy alone might be enough to generate interest in this insect. But now consider that the primrose moth is Pepto-Bismol pink with a lemony band at the tips of its wings. In that pink presentation and probing proboscis, the primrose moth offers us a lesson in form, function and evolution.

Primrose moths (Schinia florida) fly about searching for the evening primrose (Oenothera biennis), a common garden and roadside plant with a dangling, elegant yellow flower. The primrose flower opens at night and then closes by day. So a visiting moth, if it sticks around until dawn, gets an intimate embrace of petals. Besides the hug, the moth gets nectar. I’m not actually sure what the plant gets out this deal. The moth doesn’t appear to pollinate evening primrose, according to botanists and scientific literature published on this particular encounter of insect and plant. In fact, the moth seems to get the best of this relationship. The female moths lay eggs on the evening primrose; when the caterpillars emerge they start munching the plant where it hurts – the flower buds.

In any event, most of the action happens at night, when the primrose springs opens its flower and the moth plunges head-long into the blossom. Even so, the alert flower watchers among us can witness, in broad daylight, this intimate meeting of moth and bloom, among the countless examples of the powerful, shared evolution of insects and plants, which you’ll see in another photograph below.

I often encounter primrose moths still buried in a blossom the day after their night of binge-nectaring. They’re like a drunk passed out at the bar at dawn. Only the moth is harder to spot than a drunk. Those pink wings are buried out of sight in yellow flower petals. The only wing portions still visible are the trailing edges, the yellow edges, which conveniently resemble the yellow edges of the primrose petals. The moth has evolved with wise camouflage so that it can sit and drink nectar, presumably unnoticed by predators.

One of my favorite naturalists, William Hamilton Gibson, says we can hardly know the evening primrose until we know its nighttime visitor. Gibson was an exuberant 19th century writer and illustrator. In his 1892 book “Sharp Eyes,” a collection of essays and illustrations through the seasons, Gibson revels in the moth and its blossom:

“Is this a mere withered, useless blossom that droops upon its stem? Is it not rather the prettiest luminous fairy tent that ever sheltered a day-dream? Last night, when its four green sepals burst from their cone, and sprang backward to release their bright, glossy petals, a small moth quickly caught the signal, and settled in quivering contentment, sipping at its throat. Its wings were of the purest rose-pink, bordered with yellow.”

Gibson continues:

“In the color of its marking, we find an outward expression of its beautiful sympathy, the yellow margins of the wings which protrude from the flower being quite primrose-like, and the pink being reflected in the rosy hue which the wilting primrose petals so often assume, especially at the throat.”

Did you catch that “beautiful sympathy?” A wilted primrose flower turns pinkish. So a primrose moth merely sitting on the stem of the plant may resemble an old flower and still find safety in the color pink. Evolution by means of natural selection (or so I assume).

What we cannot see in this little drama is the moth’s proboscis lapping nectar from the base of a primrose blossom. But we can imagine it. Take a close look at the flower. It has a long, slender tube with nectar, called the hypanthium, below the base of the petals. It’s a long reach for a moth seeking nectar. No matter. In nature form follows function. The moth unfurls its built-in drinking straw for a sweet reward, much as we depend on our drinking straw for that last half-inch of a favorite milkshake.

So, this summer, get your favorite milkshake or maple creamee to go – and enjoy it in the good company of the primrose and its illustrious visitor.

You’ll smile when you find it. And its elegance will weaken those knees. You’ll drop to the soil to dwell with two tiny pink flowers dangling from a wispy stalk. Then, in the presence of Twinflower, you’ll wish you were three inches tall.

So here’s a tradition continued. I blogged on Twinflower last year. I’ll blog on it every June for as long as I am able. This is, after all, the the most elegant plant in the woods.

Northerners across the globe can enjoy Twinflower. Among its many delights is that it is circumpolar, occurring in cool temperate forests around the globe. It’s a dainty plant thriving – here and on the far sides of oceans – in climates and latitudes a bit harsh on humans.

It is also Carl Linnaeus’ favorite flower. A botanist, physician and zoologist, Linnaeus is often depicted holding Twinflower. And it is only fitting that Twinflower (Linnaea borealis) is named for the father of modern taxonomy, who laid the foundation for binomial nomenclature.

Twinflower is my favorite as well. I may yet see it in Linnaeus’ home country when I travel to Sweden some day (where I’ll also watch some of the best ice hockey in the world). Then, in Twinflower’s presence, the Earth itself will seem smaller, its continents joined by a tiny plant with nodding flowers.

For now, enjoy Twinflower where you find it. Here are a few more images, including one looking up into the corolla.

Spring beauties, for those who haven’t had the pleasure, are perhaps the season’s gentlest and most charming flowers. This diminutive plant stands only a few inches tall, with a couple of oval leaves (opposite) on each stem. The five petals in each flower are white with delicate pink to reddish veins.

Spring beauties are the flowers of your dreams. They’re among the first blooms of the year. They adorn the earth. And viewed up close through a hand lens, their good looks can make your knees buckle. Or, as one newly enlightened person said after one of my wildflower walks, “You haven’t lived until you’ve seen spring beauties through a hand lens.”

Bumble bees and spring beauties have a kind of mutual attraction. But this one is almost like beauty and the beast. In the woods one day, when the robust and fuzzy bee would land on each gentle spring beauty flower, both flopped to the forest floor under the bee’s weight. That didn’t deter the buzzer, however. It hung upside down on the bloom, sucked down nectar (I assumed), got brushed with pollen and moved on to the next flower for another feeding and flop to the earth. I laughed out loud as I watched.

That bee-beauty encounter is some of what I adore about the outdoors. It’s enough to see and enjoy a spring beauty alone – or any flower for that matter. It’s even better to look longer – and to watch pollination in action or whatever else might be happening around you in the woods.

Consider the pair of White-breasted Nuthatches I noticed on my walk away from the bee and the beauty. They’re the chunky birds with dark backs and white undersides that walk down the tree trunks. A male had just landed at his nest hole in a large sugar maple with a bill-full of insect. The female poked her head out from inside the hole to receive the meal from her mate – almost a sure sign that she’s incubating eggs.

I stayed around for the long, slow look. The male went off again foraging. He located a metallic wood-boring beetle (family Buprestidae), wedged it into the bark of another maple and began to peck away at its bronzed metallic shell. The beetle popped loose and fell to the ground. I picked it up, made a quick identification and returned the beetle to its proper place on the food chain.

Meanwhile, the male nuthatch was back at the nest hole, his bill packed with more insects and perhaps some vegetation. And he was using the package to dust vigorously the opening around the hole. This sweeping activity, often observed in nuthatches, may serve to mask the scent around the cavity to keep squirrels or other predators from noticing the nest.

The rest of my walk continued with other long, slow looks: a male Common Grackle fanning his wings and tail feathers in macho-like display to another male on a branch above; a Yellow-rumped Warbler snatching insects on the wing; and, finally, a Common Snipe making his eerie, winnowing courtship sounds in flight. I could see the snipe fan his tail to produce this sound as he plunged to earth – all in search for a mate. (Hey, it even turned me on.)

Slow birding at its finest.

April is the cruelest month, breeding

April is the kindest month. The forest returns with cold desire. Blades of wild leeks slice through the soggy, brown remains of autumn to release sweet-onion perfume. A ruby-crowned kinglet, his head ablaze, sings a hurried tee-tee-tee-tee, tew-tew-tew-tu-tu-tu-tu, teedle-dee! teedle-dee! teedle-dee! Spotted salamanders, black with yellow polka-dots, slimy slithering clowns, crawl by night to forest pools for their vernal orgy. The spring beauties, bolts of pink lightning on soft petals, meditate in misty woods. April leaves no sense unfulfilled.

T. S. Eliot’s April is a month of physical life and spiritual death. So in addition to my prose above, here below, in shades of red, is a visual and spiritually rich tribute to April: Ruby-crowned Kinglet, speckled alder catkins, a female beaked hazelnut flower and a Baja fairy duster in the Arizona desert.