August
The calendar tells us that the end of summer is fast approaching, but we avert our gaze. It is simply too hard to imagine the sunhats and tubes of sunscreen on the table by the front door being replaced by woolly hats and thermal gloves; or high-grip, lined boots taking the place of open-toed sandals and bare feet. This month, the cycles of heat and thunderstorms intensify in dripping humidity, while the maximum temperatures gradually decline. In the closing days of the month, the hills may even be shrouded in early morning mist. Meanwhile, the cicadas are buzzing loudly all day, and the crickets are calling day and night. Embrace the cacophony. There is no alternative, for there is no relief from the noise. A second “no alternative” is that the slow, gentle vacation season is drawing to a close. University students are returning to town. The slow trickle during the opening weeks is a prelude to a weekend tsunami of parental cars later in the month. All too soon, students will be swarming in all the usual places, and the academic year will begin again.
By and large, the natural world continues its seasonal cycle unperturbed by the abrupt and arbitrary transitions in human affairs. My essays for August start with a celebration of the creatures that luxuriate in the heat of summer, especially turtles and butterflies (“High Summer”), and I offer no apology for returning to the glory of summer butterflies in the closing essay (“Summer Butterflies”). Between these essays, I take a journey to yesteryear, or more precisely, 390 million years ago, when the local terrain was a shallow sea near the equator and inhabited by unfamiliar animals (“Lamp Shells”). I also take time to consider the amazing biology of the biting insects that plague our August lives (“Blood on the Menu”).
High Summer
Some say that high summer is the time around midsummer when the day length is at its peak, but many argue that we need to wait another six weeks or so for “real” high summer. Wait until the bones are warmed right to the marrow, the heart (or many hearts if you are an insect) is warmed to the cockles, and the roots are warmed all the way to the farthest tips. High summer is the time when my bread dough rises in an hour. It is the time when some people start to complain and shove noisy air conditioning units into their windows while others luxuriate in a world that has forgotten what it feels like to be cold.
In the competition for who loves the warmth of high summer the most, first prize must go to the painted turtles. They sit in long rows on rocks or logs just above the water level, a haphazard mix from tiny youngsters to ten-inch-long mature females, their dark shells glinting in the sun. Each turtle extends its long neck, facing its black head streaked with bright yellow stripes to the sun. When space is limited, a smaller turtle heaves itself onto the shell of a larger individual, double-decker style. I’ve never seen a triple-decker. Perhaps these turtles lack the agility to climb so high, or perhaps the bottom one objects and twitches, toppling the climbers off. Every now and then, a basking turtle plops into the water for a snack. It may swim to the bottom of the pond where it gives chase to a small fish, dragonfly larva, or shrimp, or it may take a munch out of water lilies or water hyacinth plants. At the end of the day, the turtles return to the bottom of the pond for a good night’s sleep.
Where there are painted turtles, snapping turtles are also usually found. The snappers remain in the water, where they paddle languidly with all four legs, their long neck outstretched at the front and long tail extended behind. From bow to stern, these beasts can be a good three feet long and can weigh twenty pounds or more. Alas, the snapping turtle is what usually goes into turtle soup (except when cheap cuts of rabbit or chicken are used).
Like painted turtles, snappers are omnivores. Anything from a worm to a small painted turtle or a young muskrat that’s looking the wrong way is fair game, together with many aquatic plants. Last weekend, we watched a massive snapping turtle work away at the lily leaves on the beaver pond at Sapsucker Woods. Its formidable jaws clamped onto a leaf, tore away a sizeable chunk, and then, after a quick munch and swallow, the great bulk of turtle repositioned itself for the next mouthful. Then it floated in the water, the top of its carapace exposed and head and tail down, occasionally lifting its head for a breath of air through its snorkel-like nostrils at the tip of its snout.
The slow-motion, drama-free lives of these turtles were accompanied by the regular banjo strum of green frogs. Still, the scene could have ended in drama because some of the frogs were using the lily leaves as floating sunbeds. Let’s hope that the snapping turtle’s underwater maneuvers create a sufficient disturbance to alert the frogs in good time. All that would be needed is a quick leap to a different lily pad before those fearsome turtle jaws take a bite.
The menu in the water can certainly be varied, but, in high summer, dry land offers one additional item in great abundance: plant nectar delivered as countless tiny meals. Sugar-loving creatures spend their days flying or crawling from one flower to the next, repeatedly extending their tongues to slurp up the heavenly liquid. The nectar comes in receptacles of many colors and shapes. There are the bright yellow wild sunflowers, much more beautiful than the commercial version, the pink joe-pye weed, the purple spotted knapweed, and the brilliant white of wild carrot and snakeroot. Warmed by the sun, beetles, flies, bees, wasps, and butterflies are endlessly busy.
Perhaps the most remarkable nectar-addicted feaster we have seen in recent days is a skipper called the little glassywing. We had superb views of this butterfly while walking through the woodland behind Ithaca College. To the human eye, this site is a bit scrappy, courtesy of electricity infrastructure, including a broad swath of forest cut back to accommodate a line of pylons. The scarlet tanagers playing high in the canopy of hickory trees and the chipmunks racing over the woodland floor weren’t bothered by these eyesores—nor were the glassywings foraging in a clump of spotted knapweed just below one of the pylons. This little brown butter-fly has spots on its forewing that are totally transparent. When I looked down, the spot appeared to be purple (because the butterfly was on the purple flower of a spotted knapweed) and if I had been able to look up from below the wing (alas, I couldn’t do that gymnastic trick), the spot would presumably look as blue as the sky.
It is unusual for butterfly wings to be transparent, but it’s certainly not unique to the glassywing. The wings of the glasswing butterfly, a nymphalid and very distant relative of the little glassy-wing, are entirely transparent, apart from the margins and wing veins. Presumably, the spot on our little glassywing is achieved by the same physics as displayed by the wing of the glasswing. Courtesy of the random arrangement and size of tiny protuberances on the wing surface, light absorption, scattering, and reflection are all minimized. Just for the record, there’s no chance you’d come across a glasswing butterfly in New York State. That species lives in Central and South America.
Although they’re unusual among butterflies, transparent wings are commonplace in many other insects. Wings are fancy extensions of the insect’s exoskeleton, and transparency appears to be relatively easy to achieve. A much tougher task is to make the entire body see-through, as in some marine animals, including some squids and various fish and jellyfish. Generally, being transparent is the very best kind of camouflage, but this doesn’t make sense for our little glassywing. I suspect that its transparent spot is a special way to flash its good health (and eHarmony credentials), a variation on the tail of the peacock. It certainly impressed me.
Other butterflies we have encountered recently have been more in-your-face spectacular than the glassywing. Yesterday, we watched a viceroy butterfly feeding from cone flowers in the Cornell Botanic Gardens. This is the butterfly that looks remarkably like a monarch but, unlike the monarch, is not toxic. Any self-respecting predator, such as a blue jay, will steer clear of the harmless viceroy. We also had the treat of watching a feeding giant swallowtail. Its enormous forewings fluttered energetically to maintain its position in the breeze, while its even larger hind-wings were perfectly stationary, like a rudder. There certainly is something for everyone in our high summer world.
Lamp Shells
We had been asked to “park efficiently” in the information packet provided before our fossil collecting trip organized by the Paleontological Research Institution. The neat line of a dozen cars on the hard shoulder of the road just north of Moravia demonstrated that we’d all paid attention to the good advice. This was the starting point for our trip. Within a few minutes, we were clambering about the base of a crumbling but mostly sheer cliff of shale, along with about thirty other people of all ages.
It’s time to reset your watch by approximately 390 million years—back to the Middle Devonian. Forget Owasco Lake and the other Finger Lakes scoured out by the last ice age, a mere twenty thousand years ago. Instead, float on your back in a warm, shallow sea at the northern end of the Appalachian basin and gaze east toward the towering Acadian mountains. Mountain streams rush down the mountainsides, ultimately reaching a soft, muddy delta where they meet the lapping waves of our inland sea. With your watch reset, your GPS should be telling you that we are close to the equator.
Now flip yourself over. For this bit, make sure your swimming goggles are firmly in place; otherwise, the saltwater will sting your eyes. Look down and you’ll see that the seafloor, perhaps a foot or less below the water surface, is smothered in lamp shells. I am confident of this scenario because the surface of the road cutting is made of the compressed remains of that seabed, now crumbling shale and siltstone that can be peeled off by hand. There is no need for a hammer. About one in three of these shale sheets contains fossilized lamp shells. We quickly developed a search image for three forms: Tropidoleptus carinatus, which looks like a small cockle; the oyster-like Athyris species; and the pretty butterfly shells of Mucrospirifer mucronatus. But that is the tip of the iceberg. There are lots and lots of species. Lamp shells take up nearly sixty pages of the Field Guide to the Devonian Fossils of New York (Wilson 2014), accounting for nearly one-third of the entire book. If you wanted to be a success story in the Devonian period, your best career choice was to be a lamp shell.
This is a good moment to introduce lamp shells. The meaty bit of the animal is sandwiched between two shells that are connected by a hinge at the hind end. One shell protects the top (dorsal) side of the animal, and the other shell protects the bottom (ventral) side. Apparently, these animals are called lamp shells because some of them look like oil lamps used in ancient Rome. Biologists, most of whom are ignorant of Roman lighting arrangements, gave them a different name: brachiopods. Neither of these names provides a clue to the most important thing you should know about these animals: they don’t do much. They just lie on the seafloor (or sometimes burrow shallowly into the sediment) and feed on little bits and pieces in the seawater that waft across their body, a process known as filter feeding. I suspect it is a rather boring way to live, but brachiopods don’t get bored because they don’t bother with a head or brain.
Brachiopods are easily confused with two other kinds of animals: branchiopods and bivalves. The first is just the result of word confusion. There’s little chance to get muddled by the animals themselves, because branchiopods (with an n) are fairy shrimps. Although creatures like fairy shrimps had evolved by the Devonian period, they aren’t mentioned in our field guide (Wilson 2014) and we certainly didn’t see any fossilized fairy shrimp on our trip.
The second opportunity for confusion is much more relevant. Lamp shells are similar in appearance to bivalves, such as cockles and oysters, which also have two shells and no head and also make a living by filter feeding. However, brachiopods and bivalves are very different kinds of animals that just happen to have hit on a similar lifestyle. The main difference is that bivalve shells are positioned on either side of the animal, not on the top and bottom. We uncovered a number of bivalve fossils on the shaly cliff. There are thirty pages dedicated to bivalves in our field guide (Wilson 2014), but the bivalve fossils we found were very small and frustratingly difficult to identify.
History has not treated lamp shells well. Fast-forward from our 390-million-year-old sea to about 250 million years ago. This was the time of the Great Dying, also called the Permian-Triassic extinction event. Scientists argue about why so many species went extinct at this time, but they all agree that lamp shells suffered terribly and never fully recovered. There are about three hundred species today, mostly living in secluded places and at the bottom of the ocean. Today’s stars of the headless filter-feeding world are bivalves, with twenty thousand living species.
Blood on the Menu
By the second half of August, the hundreds of acres of old field habitat at the Lindsay-Parsons Biodiversity Preserve are transformed into a mass of brilliant yellow goldenrod, asters, fleabanes, clovers, and milkweeds—all much enjoyed by pollinating insects. This site is definitely worth a visit, but we have learned from experience to go prepared, meaning we need to wear long pants and a long-sleeved shirt, with every inch of exposed skin doused in insect repellant. Butterflies aren’t the only insects that enjoy the preserve.
Although the day was forecast to be sunny, ideal for pollinating insects, the conditions changed rapidly to overcast and very muggy. We walked along the path through the brief stretch of woodland from the trailhead to the old fields. As we reached the end of the woodland, we saw a man returning from his visit to the preserve. He looked haggard, as if he’d had a bad night. He jerked his head toward the fields behind him and said, “It’s buggy out there.”
He was right. Within a minute in the old field habitat, we realized that this was warfare, and we were the enemy. Amid a perpetual whine of mosquitoes and swarms of other unidentified insects, the only strategy was to keep moving. We could easily outpace a mosquito, whose top speed is no more than 1.5 mph, and the blackflies and biting midges are even slower. Still, it wasn’t a good day for hanging around birdwatching or identifying pollinating insects.
Keeping moving sounded sensible to start with, but we soon discovered two problems. The first was that we got hot and damp walking in conditions that felt like a steam room in a health spa. Rivulets of sweat were running down our backs, and bug spray– laced sweat seeped into our eyes and dripped off the end of our noses. Unpleasant, yes, but a minor discomfort compared to the second problem: we were advertising our presence to the ravaging hordes. We must have smelled so delicious. All that warm carbon dioxide was now mixed with an enticing bouquet of volatile ammonia, acetic acid, lactic acid, ketones, and more. Another gang of biting insects was ready and waiting as we took each step forward.
Why do they love us so much? Whether it is mosquitoes, biting midges, or blackflies, it is only the female of the species that loves us, and her love is short-lived. She needs just one meal of protein-rich blood to make her eggs. Otherwise, blood is strictly off the menu because the iron in the hemoglobin pigment of blood is toxic and causes her lots of trouble. Most of the time, her food choice matches that of the adult male, which feeds on flower nectar and honeydew. Since they spend so much time moseying around flowers, these insects, which we label as blood feeders, are also pollinators. Not much is known about their pollination services, but a few plant species are absolutely dependent on mosquitoes. One is the blunt-leaf orchid, which likes swampy northern forests, in Canada down into New York State.
I am sure that the legions of insects after our blood at Lindsay-Parsons are the consequence of the large pond and swamp at the far end of the preserve. That’s where the blood-fueled females lay their eggs and where the larvae wriggle, feed on microbes, grow . . . and, in due course, join the merry bloodthirsty throng in the old fields. The water habitat at Lindsay-Parsons has nothing to do with the rivers that rush through gorges and tumble down the cliffs as waterfalls near the Finger Lakes—nor is it another of the many bowl-shaped kettle holes, created as the glaciers of the last ice age retreated. Instead, the architect of the pond at Lindsay-Parsons is the American beaver. These astonishing animals dammed a small stream with the branches of trees that they felled with their vicious, bright orange incisor teeth and then dragged into position. Inside the resultant pond, the beavers have built their home, where they are well-protected from foxes and coyotes, which appear not to enjoy swimming for their dinner. At this time of year, the beavers are starting to stock their pond with an underwater larder of tree branches to keep them going through the winter. This is all very well for the beavers, but their engineering kills many trees. We followed the path around the pond, a landscape of utter devastation or haunting beauty, depending on your perspective.
We reminded ourselves that we had come to the preserve for the pollinating butterflies and bumblebees. We did spot a few individuals, but we didn’t linger. Somehow, we were far less motivated by these species than by the hawker dragonflies and kingbirds that were gorging on our tormentors.
We returned to the junction between the bug-ridden old fields and the edge woodland by the trailhead. We were about twenty yards from the junction when we saw a young man emerging from the woodland. He was carrying a large camera, with the clear intention of doing some dedicated photography of the beautiful preserve. He called out “How’s it going?” with great enthusiasm, presumably wondering why were covered up on such a hot day. Within minutes, he would rue his shorts, sleeveless vest, and sandals.
Summer Butterflies
As we approach the end of August, I realize that it has been a good summer for butterfly spotting. We have clocked up nearly thirty species.
To get some context, let’s go back 90 million years. That’s when day-flying butterflies are believed to have evolved. They probably arose from something a bit like a silk moth or an owl moth. We tend to talk about “butterflies and moths” as if they are partners of equal standing, like Laurel and Hardy or Abbott and Costello, but butterflies are really a minority. For every species of butterfly, there are seven, possibly eight, moth species. Butterflies get the limelight because they are fun, and many are very beautiful, whereas most moths are tiny, drab night fliers that are fiendishly difficult to identify.
The butterflies we have been admiring this month make up a story in five parts.
It’s logical to consider the skippers first. That’s because they are among the most ancient of the butterflies, and they look like it, with their sturdy body and short wings that are often held open when the butterfly is at rest. When I lived in the UK, I tended to think of skippers as the poor relations of the other butterflies. That’s partly because of the long-standing arguments about whether they are really butterflies (we now know the answer is yes), but it’s mostly because British skippers are a bit limited. Take your pick among the three most common species—the small skipper, the large skipper, and the dingy skipper—all in shades of brown, with the wingspan of the large skipper reaching no more than 1.2 inches (3 cm). Skippers are much more diverse and interesting in the New World. Come to New York State, and enjoy up to twenty-seven skipper species. Some have wonderful names. For example, the Hobomok skipper enjoys the nectar of our backyard cone flowers; the male of the species shows off a bright orange patch on his underwing as he sucks on sweet nectar. My favorite is the silver-spotted skipper, a good two inches (5 cm) in size and sporting a broad splash of brilliant white on the underside of its hindwing. This is special for anyone who started life in the company of small, dull British skippers.
Next come the lycaenids, meaning the blues, coppers, and hair-streaks. My top lycaenid event of this year was a banded hairstreak that settled gracefully on my sunhat for several minutes while I was walking in Watkins Glen State Park in early July. The oak, hickory, and black walnut trees overhanging the gorge at Watkins Glen provide the perfect resource for this woodland butterfly, which lays its eggs on the twigs of these trees. The eggs persist for nine months or so through the winter, unless they are eaten by a chickadee or other hungry beast. The caterpillars emerge in the following spring to munch on the trees’ catkins and quickly grow before pupating for next year’s butterfly show.
Some lycaenids are much more showy than the predominantly gray-and-brown banded hairstreak. In particular, the spring azure is a wonderful violet-blue. Don’t be taken in by the name. Although it is on the wing by early May, this species (or probably cluster of species) is with us through the summer, usually fluttering low in the vegetation beside trails in the forests and meadows. Spring azures are among the many blue butterflies that form a symbiosis with ants. The caterpillars secrete a sugary solution from glands all over their hairy bodies, and the ants lap it up and protect the caterpillars from birds, spiders, and other natural enemies.
Two down, three to go. Let’s move on to the nymphalids, also known as the four-footed butterflies. That’s because they like to stand on just four of their six legs, curling their forelegs up under their slender body. The four-footeds are very diverse and include the admirals, tortoiseshells, fritillaries, and Baltimore checkerspot (see the essay in “July”), along with the most famous North American butterfly, the monarch. We are getting into the world of big, conspicuous butterflies.
We have especially enjoyed watching one of the four-footeds, the meadow fritillary, which, as the name suggests, flies in meadows and fields, often in large numbers and throughout the summer. The caterpillars eat the leaves of violets, and they would rather die than eat anything else. You’d imagine that Mom would lay her eggs on violets, but she doesn’t. She lays them singly and rather haphazardly on twigs, blades of grass, or other plants, and she leaves the tiny caterpillars that hatch to do the hard work of finding a violet plant on their own. Meanwhile, the negligent parents flit around, indulging in the nectar of composite flowers, including dandelions in spring, sunflowers around midsummer, and asters toward the end of the season.
Onward. Our march takes us next to the pierids, meaning the whites, yellows, and sulfurs. Alas, some gloriously named species don’t come our way. There’s the sleepy orange, which gets as far north as southern Pennsylvania, and the southern dogface, which can be found from Florida to Texas. But we often see clouded sulfurs fluttering in fields and meadows, and we have had excellent views of the orange sulfur, flashing its wings of pale orange with a broad black margin. For better or worse, the most common pierid is the cabbage white, which arrived in the eastern US during the 1860s. It hailed from Western Europe (probably England) and likely arrived in a shipload of turnips or cabbages that berthed in Québec, Canada. The cabbage white promptly spread across North America, probably assisted by railroad transport of fresh vegetables. In just twenty years, it was found coast to coast, except in deserts and the far north. Despite every effort to control this major butterfly pest, the cabbage white continues to flourish. It is by far the most common butterfly in our backyard.
Finally, we have the swallowtails. They are such beautiful butterflies: the eastern tiger, black, spicebush, and eastern giant. The eastern tiger is common, regularly swooping and gliding through the garden on its yellow-and-black-striped wings. Best of all, we have recorded all four swallowtail species in our backyard this year.