Monday, August 30, 2010

August 28, 2010

On Saturday I wandered down to the mailbox, camera in hand, on a dew-soaked morning that was chilly even though the sun was well up. Summer's winding down--the goldenrod has just started to bloom and the teasel has died back, but there's still some life to be found in it.

Differential grasshoppers (Melanoplus differentialis) are common pests, but here the cold nearly stilled them and they looked like intricate sculptures.

On the milkweed next to the mailbox, I found this year's first swamp milkweed leaf beetle.

Here's a field cricket (Gryllus pennsylvanicus)--in the field!

There was a lot of bird activity. The neighbor's pair of house wrens scolded as I walked past and there was a couple of chickadees feeding in the cedars. The chickadees here all appear to be Carolinas but we are within the Carolina-black-capped hybridization zone and they can't be told apart except by direct measurements.


Thursday, August 26, 2010

Milkweed puzzle


The common milkweed (Asclepias syriaca) in my field is a famously toxic plant. It produces cardenolide alkaloids in its foliage, cardiac toxins that affect sodium and potassium levels and interfere with heart contractions. It also produces a sticky latex sap and leaf hairs to foil herbivory.


It is common knowledge that the Monarch butterfly caterpillar (Danaus plexippus) which feeds on milkweed has evolved to tolerate the plant's toxins, sequestering them in its body, rendering it toxic to its own predators.

In the course of wandering my field with my camera for the last year, I have found that the milkweed plant is host to many more insects than Monarch larvae. Even if I can't find anything to photograph in the rest of the field, there's always something to be found on the milkweeds. And it turns out that many of these insects pull off the same trick--consuming the plant with impunity and using the toxin to ward off their own enemies. Some of them, in addition to tolerating the cardenolides, have evolved techniques to disarm the plants other defenses. Monarch caterpillars first clear an area of hair before feeding and also cut the latex canals in the leaf, reducing the pressure of the sticky sap. Anurag Agrawal's video discusses this topic in depth (http://cybertower.cornell.edu/lodetails.cfm?id=481).


Another Lepidopteran, the Milkweed Tiger Moth caterpillar (Euchaetis egle) eats milkweed foliage.


The Large Milkweed Bug (Oncopultus fasciatus) lays its eggs on the milkweed and its nymphs, along with the adults, feed on the plant's juices and maturing seeds.


The Red Milkweed Beetle (Tetraopes tetraophthalmus) larvae bore into the stems and roots of the plant to feed.


The Swamp Milkweed Leaf Beetle (Lasidomera clivicollis) consumes the foliage and the flowers.

All these milkweed specialists advertise their own toxicity with bright, apsomatic coloration. This warns off predators that would otherwise eat them. It works so well that some non-toxic insects [again famously, the Viceroy butterfly (Basilarchia archippus)] wear the same colors to avoid predation.


The milkweed does depend on insects for pollination, and produces large, fragrant flower clusters. However with the exception of the occasional Monarch adult, the pollinators I've observed are different species than the milkweed specialists above.



It makes me wonder how this is working for the plant. It spends energy producing toxins and defenses that many insects have evolved to disarm. The plant toxins protect the insects from vertebrate predators, but the insect work-around must be fairly easily developed since it occurs in at least three orders. And while the milkweeds do survive to set seed, by the end of the summer they are pretty ragged. Are milkweeds just barely protecting themselves against these insect specialists, engaged in an arms race with them as Anurag Agrawal suggests? Do these specialists benefit the plant in some way? Or is the milkweed protecting itself against some other rapacious insect that is completely foiled by the plant's defenses? Vertebrate herbivores--geese, bison, or deer? Food for thought.



Tuesday, August 17, 2010

Killdeer Plains--August 15, 2010

On another humid, overcast morning, Steve and I set out for Killdeer Plains. The 9000 acres are managed for wildlife and hunting by the ODNR. It occupies an area that was formerly prairie and some remnant spots are managed for prairie vegetation. Even though it is only 1/3rd the size of the original prairie, the open vistas are startling to see in Ohio.



We usually come here to see the birds. The raptors are spectacular--there are nesting bald eagles here and in winter, scores of harriers and rough-legged hawks, and once we got a good look at a merlin. Owls too--it’s a well-known winter roosting spot for long-eared and northern saw-whet owls, and short-eared owls hunt the fields. In winter, flocks of horned larks, snow buntings, and longspurs are common. We nearly always see trumpeter swans, and once we saw American white pelicans on the marsh.



Although we did startle a great blue heron, today belonged to the insects. Mixed groups of puddling butterflies were everywhere. Male butterflies do this to ingest minerals which are then transferred to the females in sperm to help improve egg viability.


Buckeye (Junonia coenia) and pearly crescentspots (Phyciodes tharos).


Red-spotted Purples (Basilarchia astyanax) and Little Yellows (Eurema lisa).


Buckeye


Viceroy (Basilarchia archippus), which famously mimics the toxic Monarch butterfly.


We missed the peak of the prairie flowers, but there were still some in bloom:


Swamp Milkweed (Asclepias incarnata), with Pearly Crescentspot,


Hairy Sunflower (Helianthus mollis),


Partridge-pea (Chamaechrista fasciculata).


Other insects were abundant too. Each time we stopped the car, horseflies swarmed around in alarming numbers.


Ailanthus webworm moths (Atteva punctella) flocked to the common milkweed.

Steve got this picture of a damselfly near the marsh.

I found a robber fly out among the prairie flowers. This one appears to be a bee killer (Promachus fitchii) which does just that, scouting its prey from exposed vegetation.

Sunday, August 15, 2010

August 14, 2010

I went out yesterday on another sodden, hazy morning not expecting to see much. The only plants blooming in the field right now are ironweed and Queen Anne’s lace--the milkweed’s long done.


But you never know. I did find some milkweed tiger moth caterpillars (Euchaetias egle)--a showy caterpillar that metamorphoses to a pretty nondescript adult moth. Years ago before the milkweed took off in the field, I tried to grow some butterfly weed (another milkweed) in my garden. It was never very happy in my shady site, and then one summer, a whole clutch of these caterpillars ate it right to the ground. Sometimes when you plant for wildlife, you get what you ask for!


Halfway down the driveway and just as I was about to turn back, a doe and fawn crossed the road and came up the hill toward me.


This fawn’s spot pattern doesn’t match that of either of the fawns I saw in July, so this is a different family.


They got pretty close before the doe finally scented me. It scared the snot out of her--she didn’t stop snorting until she got to the other side of the soybean field behind the sumac jungle!

Saturday, August 14, 2010

Butterfly tree

I’ve had a creepy curiosity in my yard all summer that I finally took some time to examine this week. About a month ago I noticed Red Admiral (Vanessa atalanta) butterflies in the front corner of the yard along the edge of my front field and the neighbor’s soybeans. I know from childhood that they are territorial and bold around people and also that you can find them in the same place every evening. Last time I mowed I got strafed by butterflies there, so I figured I’d go look around when I had time.


When I went out in the evening, I found a group of 5-10 butterflies, mostly anglewings--Commas (Polygonia comma) and Question Marks (P. interrogationis), but also a Red Admiral and a hackberry butterfly (Asterocampa celtis) flying around a ragged, half-defoliated slippery elm (Ulmus rubra Muhl.) sapling in that corner. The butterflies would fly around in groups and then occasionally land on the tree. Elm species are host plants for the anglewing caterpillars, but not the Red Admiral. All of these species are territorial as adults and the adults feed on tree sap as well as rotting fruit and dung. As I watched, I noticed bees and flies hanging around the trunk too. A few birds flew in and out of what was left of the canopy--I think they were female indigo buntings.


Question Mark Butterfly



Hackberry Butterfly


Once I got around to the soybean side of the tree where I could get close look, it was clearly a sapfest. Butterflies swooped in and out, and around my head, a troop of horseflies swarmed on the trunk for minute, then disappeared, and a bald-faced hornet made an appearance. There was even an adult cicada in the branches. There was a lot of activity and buzzing around--there was a definite “creep factor” at work here!

Horseflies (Tabanus sp.). Only the female horsefly drinks blood, so these are probably males.



Cicada adult






Sunday, August 8, 2010

The Sumac Saga

When I moved here 15 summers ago, the front acre was a long, sloping lawn with young conifers planted along the eastern boundary. I decided to let it go wild, just planting more trees and shrubs to fill in the boundary, making a mixed hedgerow. Now it is at an old-field stage, filled with milkweed, goldenrod and asters and young ash, mulberry, and red-cedar saplings.


About 10 years ago Steve planted a staghorn sumac (Rhus typhina L.) fruit in a coffee can and left it on his back porch. Two years later, it sprouted and we transplanted it into the hedgerow where it thrived. I really thought this was a good idea at the time. It’s native, and the sumac I’d seen along roadsides grew in small groups with an attractive, open, antler-like form.


Unfortunately though, despite the annual beating it takes from the deer, it has formed a dense clonal thicket and is marching tumor-like across my field. None of my guide books mentioned this tendency (although I have recently found this information online) and I had a bad moment a few years ago of thinking we had planted tree-of-heaven by mistake. But no, sumac it is.



It’s beautiful in the fall, and the wildlife does make use of it, but nothing else grows within it’s boundary.


I’ve read that it can be controlled by cutting it back in July and August, but that the sap can produce a poison ivy-like rash. I don’t want to eradicate it entirely, but I’m not sure how taxing it would be to have to cut it back each year. The clones are apparently relatively short-lived and it will not thrive in shade, should the saplings manage to top it. But for now it’s joined in the battle among the other invasives in this field--multiflora rose, Canadian thistle, and teasel competing for this space.


Saturday, July 31, 2010

Down In the Woods--July 25, 2010

Just past dawn, ignoring the heavy atmosphere and impending rain, I escape into the woods that were once my childhood sanctuary and playground. As soon as I descend the ravine, the canopy closes over, enveloping me in twilit gloom, rainforest-humid. Mosquitoes whine around my head and memories crowd in.


By the time I was in grade school I was allowed to come down into the woods by myself. I soon learned that if I stayed still and quiet, the woods would come to life around me. I enjoyed being alone there, and I still am most comfortable by myself. It’s a tract of about 100 acres, so my treasured solitude was real, and I began to get a sense of the forest as sacred.


The once well-defined path has blurred from disuse and deadfall and I carefully pick my way down the steep hill. This slope was once a riot of wildflowers in the spring, and at this time of year, high summer, it was covered with vegetation. Now I see little greenery, just disturbed leaf litter from foraging turkeys. Here is where I used to find white and rarely, red trilliums, the mottled red and white berries of false Solomon’s seal, and once, a lacy maiden-hair fern.


The forest here is a mix of trees (officially a mixed mesophytic forest); giant red oaks and sugar maples, beeches, tulip poplars, and a patch of sassafras. Hemlock and maple-leaf viburnum grow here too, both relics of the last glacier. Last logged in the 1870’s, the forest here bears the hallmarks of an old-growth, unmanaged stand. The terrain is hummocky from the rootballs of uprooted trees, and there are few stumps. Logs lie decaying on the forest floor and muscular grapevines twine up into the canopy undisturbed. Although there are several old giant trees, there are many more younger trees waiting to sprint up in the next patch of light.


The woods is quiet on this oppressive day except for the gull-like alarm calls of a red-shouldered hawk as he spots me, and farther back the “pee-o-wee” of an eastern wood-pewee and the wood thrush’s flute. The adjacent Hach-Otis property has been preserved as a bird sanctuary since 1944 and when I was a child, I often saw beautiful, unusual birds. Once, when I was very young, in an open patch near the yard the buzzing, looping display of a male hummingbird, startled, and then entranced me. The high canopy harbored birds that I only rarely saw--the flame of a scarlet tanager and the incessantly-singing red-eyed vireo. One rainy spring Friday, I came home from school to find the woods full of jewel-like warblers. Termed a “fall-out,” migrating songbirds congregate before crossing an obstacle (in this case, Lake Erie) until weather conditions are right. I was already interested in watching birds, and after the weekend was over, I had seen nearly 30 species of warblers.


As I reach the bottom of the hill a soft rain starts, but the canopy keeps me dry. The short walk to the stream was once overgrown and choked with jewelweed, but is now browsed bare by deer. The nameless stream I once scoured for frogs has eroded deeply here between the banks at the crossing, exposing a swath of blue clay, and the latest bridge lies twisted in the water. The stream cuts through clay here, but further downstream, it turns and abruptly becomes lined with round glacially-transported rocks.


I continue along and descend into the floodplain next to the Chagrin River. This place has always had it’s ghosts and artifacts; a nearly visible imagined house, a cairn of small round glacial rocks, piles of plastic pots washed downstream from the now-defunct nursery, scattered daffodils blooming out of place among the wildflowers in the spring. It is rumored to have once been a nudist camp. Today I find more pots, and curiously, a small stump full of golf balls.


Away from the river, I find wild leeks flowering in patches of bare soil, but closer in, spicebush and multiflora rose shrubs rise to crowd the path and the weeds that I remember finally appear forcing me to pick my way carefully to the river trying to avoid the electric “zing” of the waist-high stinging nettles. The invasive purple loosestrife and towering Joe-Pye weed bloom at the water’s edge.


The river today is high and turbid and I decide not to risk my camera trying to wade in. I startle a great-blue heron into croaking flight and a female mallard flaps away upstream. As a child, I often found the pterodactyl heron footprints in the mud along the river without realizing what made them. Then one morning I was rewarded for rising early by spotting the bird itself silhouetted at dawn on a rock at the river bend. The cliffs rise to each side of me, but this is a low spot, often completely flooded during ice-melt. My parents respected the flood-prone Chagrin and I was not permitted to come here until age 10, but after that, a new world opened up.


These cliffs of clay and shale tower 150 feet over the wide valley which the Chagrin has re-carved through glacial debris deposited 10,000 years ago down to the Devonian-age Chagrin shale lining the riverbed. Just upstream of this spot, the river crosses from the hilly topography of the glacial moraines to the more level ancient lake plain. So although the surrounding terrain is rugged, the river starts winding lazily here, dumping sediment as it slows. The cliffs are unstable and erosion-prone--dusty and crumbling under bare feet when dry, slippery with patches of foot-grabbing quicksand when wet. My friends and I climbed these often, testing ourselves against gravity, sometimes learning exactly what a toe-hold is.


While I learned the value of stillness early, my friends and I played here too. We were the last free generation of children running through the woods unencumbered by cell-phones, water bottles, sunscreen, or even shoes. I was bound only by my father’s piercing whistle calling me to dinner. We took our chances, swinging on grapevines over deep ravines, and happily risking our necks on the cliffs. While I often returned home wet, scratched, and bleeding, no one I know was ever seriously injured. Later, we risked stolen cigarettes and first kisses in the cover of the trees.


I retrace my steps back out of the floodplain and start the climb up to the cliff top along the ridge. The property here is privately owned, and I come upon a tract that has been logged. It’s clearly been done carefully and selectively; I can find no trace of heavy machinery and younger trees have been left behind, but the old giants are gone.


As a child, I worried about losing the forest this way, and bulldozers still loom in my nightmares, but the Hach-Otis tract is now a nature preserve and most of the landowners seem to understand what a treasure they have. Today I don’t find any more signs of human disturbance than I ever did, not even a footprint. The wildlife has come back prodigiously from the birds and fox squirrels of my childhood. Raccoons were garbage scavenging pests, rarely seen during the day. The only evidence of deer was one or two delicate chains of tracks passing through each summer although I desperately wanted to see one. Once I did find a woodchuck and its burrow and the animal was so unfamiliar to me that I had to look it up. Now the fox squirrels have been joined by gray squirrels of all shades, and the raccoons have become a true rabies-carrying plague. Deer have decimated the wildflowers and herbacious layer in the woods. Flocks of turkeys haunt feeding stations, dust-bathe in yards, and peck at their reflections in the sides of vehicles. Foxes and coyotes are common, beavers and otters have returned to the watershed, and bears and bobcats are rumored.


Although the wildlife burgeons, the trees themselves are in jeopardy. While there is now hope that the chestnut may be returned to it’s range, most of the other tree species have their own exotic pathogens. The beeches are crumbling from beech bark disease, an unfortunate interaction between an exotic scale insect and either of two fungi. The once-flourishing dogwoods are almost gone, victims of a fungal disease and oaks are periodically defoliated by gypsy moth caterpillars. The emerald ash borer and hemlock woolly adelgid are on the doorstep, seriously threatening both of these tree species, and thus, the whole community is imperiled.


As the ridge steepens and opens up on my right, I can see the Hach-Otis bluffs across the wide river valley. The old trail, once tracing the very edge has completely eroded here, and at the top, most of the old “Moss Meadow” has slumped down the cliff face too. When I was young, this unique community was an idyllic spot. The southwestern exposure created a hot, dry windswept area. The top of the cliff was a clear moss covered area affording a commanding view of the river valley. The few trees at the edge were stunted and wind-tortured. I used to come here to look for kingfishers and hawks, and I often got to see a pair of red-tails at eye level as they circled over the valley. Now some of the moss remains, but trees crowd the view from the edge.


The scale of this place remains undiminished in adulthood. The cliffs still soar, producing a swoop of vertigo. A sudden gust of wind makes me turn to the now charcoal sky to the north. The thought of walking back in a wind storm under these widow-maker trees gives me a thrill of real fear. The arduous hike remembered from childhood is still difficult and I know I won’t be able to get to shelter before the storm hits. I am lucky--the wind dies down and the storm subsides to just rain. I hike quickly back until the final hill. This was a formidable obstacle in childhood, mentally separated into seven sections with rest stops between. Today it’s still a struggle and I stop more than once despite the soaking rain.


As I leave the forest, I realize anew how much it has shaped me, and I hope to be able to return soon.


Camp, Mark J. Roadside Geology of Ohio. Missoula, MT: Mountain Press Publishing Company, 2006.


Ostrander, Stephen. Natural Acts of Ohio. Wilmington, OH: Orange Frazer Press, 1994.