August 24, 2010 § 2 Comments
A BUTTERFLY BONANZA!
Recently I returned from a trip to southwestern Ohio to visit my sister-in-law Amy, who is recovering from hip replacement surgery. She is mending beautifully and determined to get back on her feet —only a few days after returning home from the hospital the visiting nurse said she was doing as well as their typical patient at three weeks out!
While Amy was resting I would grab my camera and head into her garden and the surrounding fields because here was a Butterfly and Hummingbird Bonanza! I encountered dozens of Ruby-throated Hummingbirds, typically feeding and frolicking in groups of threes and fours, and many differing species of butterflies. For the most part, the butterflies that I photographed are the same species of butterflies that are found on Cape Ann and throughout New England. Having no expectation of encountering myriad butterflies, in both range of species and in legions of each, I had not planned accordingly and only packed my Panasonic Lumix. I love this camera, but like all cameras it does have certain limitations. Lesson learned—that is to say—always travel prepared for anything to happen!
Amy is a working architect and, as time and her work schedule have permitted, she has (along with her recently deceased dear husband Tim) redesigned and restored her lovely old farmhouse and gardens. There are several cozy porches and a deck under construction in which to sit and observe the wildlife dramas that play out almost daily.
What makes Amy’s garden so inviting to the pollinators? The old farmhouse is approached by traveling down a crushed limestone driveway. On either side of the drive are fields, either overgrown with wildflowers, or maintained as mowed grass. The fields meet the forest edge. There are several neighboring houses along the drive but privacy is afforded because the houses are sited a fair distance apart and because there are naturalized arrangements of native trees and shrubs. Flower borders are planted in close proximity to her home and also further afield. Beyond the flower borders is a large vegetable garden, approximately twenty feet deep by sixty feet long, with a row of sunflowers bordering the back length and a cheerful patch of zinnias running along the fore edge. Beyond the vegetable garden is a vigorous crop of blackberries and beyond that is a clump of wildflowers, including common milkweed (Asclepias syriaca), which were covered in Monarch caterpillars, and the tall growing New York Ironweed (Veronia noveboracensis), which was in full bloom. All of these elements provide clues as to why Amy’s garden is a haven for the butterflies and hummingbirds. Additionally, adjacent to the house is an old peach tree, which bears great quantities of fruit. Because Amy has been under the weather from her hip injury she was not able to maintain the peach tree this past season. The peaches were falling to the ground and rotting—not really a bad thing as you will soon see—imagine the not intolerable odor of vinegary peach juice.
The combination of the atypically lengthy stretch of hot, sultry weather, punctuated by soaking rain storms, along with the salt and mineral-rich limestone driveway, flowering plants, wildflowers, surrounding woodlands that provide shelter and larval food for caterpillars, hummingbird feeders, and rotting peaches—all work in tandem to create a paradise for the pollinators—bees, butterflies, and hummingbirds.
In the morning I would find Buckeyes, Question Marks, and Red-spotted Purples drinking salts and minerals from moist patches in the driveway. Hungry families of Ruby-throated Hummingbirds were noisily nectaring from the flowers and feeders; one feeder is sited beneath the peach tree and the other about twenty feet away, under the lilacs, a hummingbird superhighway of sorts, with inviting nectar flowers along the route. The male and female hummingbirds are both territorial and, when encountering anything out of the ordinary (my camera and I, for example) will threaten by whizzing and whirling, albeit harmlessly, close to your head.
By mid-day the hummingbird and butterfly scene was full underway. Spicebush Swallowtails at the Rose-of-Sharon, tiger swallowtails, yellow sulphurs, Eastern Tailed-Blues, Monarchs, checkerspots, and angelwings nectaring at the zinnia patch, phlox, and lobelia, and most remarkable of all, were the number of butterflies that were drawn to the pungent lure of rotting peaches. By late afternoon dozens of Hackberry Emperors, Red-spotted Purples, Question Marks, and Red Admirals were to be found intently imbibing from the fermenting peaches, and by day’s end, I believe they were drunken butterflies, making extraordinarily easy subjects to photograph. I would be down on my hands and knees with the lens held so closely it was nearly touching them, and several times that did happen as they fluttered or hopped onto the camera’s lens. In the lingering remnants of late day’s light, the hummingbirds were there again at the feeders and flowers, and all manner of swallowtails in the wildflower meadow were nectaring from the New York Ironweed.
The three different species of butterflies in the above group of photographs have a unique relationship. The Red-spotted Purple and Spicebush Swallowtail (both palatable to predatory birds) are thought to have evolved to mimic the Pipevine Swallowtail (center photograph), which is highly toxic and foul tasting.
I was sad to say goodbye to my sister-in-law but glad to return home to my family. My unexpected yet welcome encounter with the butterflies of Southwest Ohio reminded me once again that butterflies are a symbol of transformation, joy, and beauty throughout cultures the world over. Perhaps Amy’s butterflies mirror the transformative journey to which she has embarked.
August 9, 2010 § Leave a Comment
Dear Gardening Friends,
I have received many emails in the past several weeks from people wondering what is the large, yellow butterfly that they are seeing perusing their gardens and neighborhoods. I imagine they are observing a tiger swallowtail–either an Eastern Tiger Swallowtail or a Canadian Tiger Swallowtail. They may not recognize it as either species because tiger swallowtails are highly palatable. Their delicate tails, and then some, may have been sheered away by hungry birds snipping. The first two photos below show a newly emerged tiger swallowtail with tails intact and a swallowtail without tails.
I wrote the following column several winters ago after having recently read A Tale of Two Cities. If you can bear to read about winter storms during this delicious stretch of warm weather, you will find information that will be helpful in identifying whether visiting your garden is a Canadian Tiger or an Eastern Tiger Swallowtail. Additional identifying photos are at the end of the column.
A Tale of Two Tigers
Recalled to Life
As seed and plant catalogues pile ever higher in my ever-shrinking office, I am culling all for sources of delicious vegetables and herbs, native plants, fragrant cultivars, and plants that will expand the Lepidoptera and songbird habitat. With inviting descriptions accompanied by enticing photographs, it is difficult to exercise restraint. Absorbed in thoughts of new life in spring, I am reminded of an incident that occurred at about this same time last year.
My husband and I had returned home from a venture along the backshore to witness the waves cresting in the aftermath of a late-winter storm. With great gusts blowing up from the south, the storm was tropical in temperature, but not in degree of ferocity. Drenched to bare skin, we came in through the cellar to remove our soaked clothing, where, to our dismay, we encountered a newly emerged tiger swallowtail butterfly, unable to fly, with its wings dragging along the cold stone cellar floor. I carefully picked it up by holding the butterfly along the sturdy leading wing margin, and brought it into the warm kitchen. Its wings had not fully unfurled and the butterfly was in distress. We provided a twig for it to crawl upon, which would have allowed its wings to hang down, and then, perhaps, fully expand. That was unsuccessful and the butterfly preferred instead to simply rest in my hands. We offered it a Q-tip soaked in sugar water and I cupped my hands and held it there for a long time, hoping the warmth would recall it to life.
Within the brief moment of time a butterfly emerges, if just one of the steps in the complicated dance goes awry, the creature will likely fail. The crimpled, wet wings are tightly compacted within the chrysalis. The butterfly pushes head first through the pupa case and upon emerging, with its crochet hook-like feet (tarsi) grasps at nearby surfaces. Body fluids are drained from the swollen abdomen and pumped through tubular wing veins (called struts) to the very outer margins of the wings. The butterfly’s double drinking straw (proboscis) must zip together, or it will be unable to nectar. For several hours after eclosing, it remains in a stationary state, the most vulnerable of positions, to allow its wet wings to dry thoroughly. The mystery of how the tiger swallowtail came to be in our basement, and why it eclosed in early March, prompted me to learn more about this magnificent species of butterfly.
The Golden Thread
Tiger swallowtails are recognized by their four rows of tiger-like yellow and black stripes and thin black tails extending from each lower wing. Canadian Tiger swallowtails are found in all provinces and territories of Canada, northern New England, and eastern New York. Eastern Tiger Swallowtails are more common from southern New England and south to Florida. We are fortunate in Massachusetts to be located where overlapping of both species occurs. Canadian and Eastern Tiger Swallowtails are closely related and were not recognized as separate species until 1991. The clearest way to see the difference is to compare wingspan. The Canadian is smaller, with a wingspan of just under 3 inches; the wingspan of the average Eastern is 4.5 to almost 5 inches— the southern female ranks as the largest butterfly of the East Coast. Canadian Tiger Swallowtails are generally a paler yellow and the darker border next to the body is thicker. When the wings are folded, the yellow sub-marginal band on the fore wings is largely continuous, not interrupted by black wing veins. Tiger swallowtails are highly palatable and, as a defense against predators, have evolved with rapid wing movements and erratic flight patterns, which make these differences between the two species difficult to discern without side-by-side specimens or photos.
Species: glaucus ~ Eastern Tiger Swallowtail
Species: canadensis ~ Canadian Tiger Swallowtail
The purpose of identifying the different species is relevant when planting to encourage tiger swallowtails caterpillars to colonize your garden. Host trees for Canadian Tiger Swallowtail caterpillars include native species of birch (Betula), black cherry (Prunus), and aspen (Populus). The Eastern Tiger Swallowtail caterpillars have adapted to a wide range of host trees from multiple families, especially wild cherries (Prunus sp., Prunus virginiana), tuliptree (Liriodendron tulipfera), ash (Fraxinus), and sweetbay magnolia (Magnolia virginiana) in the Deep South. Both species are generalist when nectaring. I most often observe tiger swallowtails nectaring at plants with clusters and panicles of small florets, for example, native buttonbush (Cephalanthus occidentalis), Joe-pye weed (Eupatorium purpureum), common milkweed (Asclepias syriaca), butterfly bush (Buddleia davidii), and Verbena bonariensis.
Adding to the challenge to accurately identify whether Canadian or Eastern, female Eastern Tiger Swallowtails may exhibit sexual dichromatism, a dark-phase that mimics the highly unpalatable and toxic blue/black coloration of the Pipevine Swallowtail. The yellow form of the females is more typically seen in our region and is similar to the males, except that the hindwings above the black margin are covered in beautiful blue iridescent scales. Iridescence in wing scales is an example of how Lepidoptera have evolved with structural color that is disorienting to predators. The flashes of light created by the iridescent scales, combined with undulating wing beats caught in sunlight, causes hungry birds to be confused. The characteristic “tails” that lend swallowtails their common name are significant aerodynamically. Airflow is directed over the wings, enabling extended glides at higher angles, whereas Lepidoptera with more broadly cut wings would normally stall.
We look for tiger swallowtails eggs on the topside of host tree leaves. The spherical, green, pinhead-sized singular eggs are not easy to see amongst the surrounding foliage. The first instars are dark brown with white markings, which resemble bird droppings (another defense against birds). Later stages become luminous light green, with yellow and black thoracic “eyespots” that mimic the eyes of small snakes. Tiger swallowtail caterpillars have yet another defense against predators. When threatened, they will evert their osmeterium (a unique horn-like appendage that resembles a snake’s forked tongue), which emits a smelly secretion.
Most tiger swallowtail caterpillars feed at night, spending the day in a rolled-up leaf mat bound with spun silk. When ready to pupate, the caterpillar turns chocolate-brown and spins a silk girdle, a “thread of life” that supports it in an upright position as it begins to pupate. The chrysalis resembles a twig, or knob of wood jutting from the trunk, and the thread holding it in place is as fine as a strand of golden thread. In the case of the chrysalis formed in late summer, the pupa enters a state of diapause and the adult emerges in spring. The same thread of life girdling chrysalis to branch will keep the pupa secure through winter snow, sleet, and ice, and during violent spring thunderstorms and nor’easters.
The Track of the Storm
Artfully mimicking the twiggy growth and withered leaves of the lantana (Lantana camara) standards we winter-over, it became clear how a tiger swallowtail chrysalis could find its way into our cellar. Prior to bringing plants indoors, we now thoroughly examine all for signs of Lepidoptera pupa. The unsolved mystery is why. The eerie atmosphere created by the tropical storm in winter, coupled with the unsettling early emergence of the butterfly is haunting still. Perhaps the electric energy and unusual balmy temperature carried by the storm caused the butterfly to eclose several months too early. Whatever the reason, I return to the not unpleasant task at hand—catalogues beckoning with plants to enhance the songbird and Lepidoptera landscape—anon to be engaged in the garden of possibilities.
It was the best of times, it was the worst of times, it was the age of wisdom, it was the age of foolishness, it was the epoch of belief, it was the epoch of incredulity, it was the season of Light, it was the season of Darkness, it was the spring of hope, it was the winter of despair, we had everything before us, we had nothing before us, we were all going direct to Heaven, we were all going direct the other way . . . ~ A Tale of Two Cities by Charles Dickens