.

April 25, 2006

We have several tiny butterflies that frequent our farm drive, even though there seems little to attract them. Most of the early ones are blues, tiny mites that fly up almost under one's feet, especially after a rain. The spring azure is often the first to appear, sometimes when old snow still hangs on, and is certainly the earliest to emerge from its pupa. Butterflies cannot fly if their body temperature is less than 86 degrees, and it is an interesting fact that the first early brood of spring azures is much darker in color than those that develop later in the year, to better absorb any warmth provided by the sun. Some other species that may also show themselves such as the mourning cloak and tortoise shell have survived the winter as adults, hidden in piles of leaves or in protected spots in outbuildings or woodpiles.

Last week, another even smaller flyer caught my eye as it fluttered by. Most butterflies have a distinctive manner of flapping their wings, even though some such as the monarch seem to fly in slow motion and others like the red admiral move about in fast forward. This insect, however, reminded me somewhat of an awkward beetle. Then, too, its color was unfamiliar, having dark top wings with large bright orange areas on its lower set. When it finally settled so that I could see it more clearly, it held its wings in a "V" shape rather than flat out or tightly together over its back. It took considerable searching through my books to identify it, but I came to the conclusion that was a least skipper, a common resident but one I had never seen before.

Skippers seem to be a cross between a butterfly and a moth. Butterflies have antennae that resemble slender stalks with knobs on the tips, while moth antennae are usually feathery looking, and skippers have butterfly-type antennae but with a hook at the tip. Butterflies and skippers are active during the day while moths are more often abroad at night. Butterflies have slender bodies, while moths and skippers tend to be stout. Butterflies are usually very bright colored, while most moths and skippers are drab. Butterflies hold their wings together over the back, while moths typically hold their wings out to the sides, and skippers let you see both top and bottom. Butterfly caterpillars are generally smooth-skinned, whereas moth caterpillars are fuzzy or spiny. Skipper caterpillars, on the other hand, are often "naked" and have an oversized head atop a tapering body. Butterfly larvae shed their skins leaving a chrysalis, while moth caterpillars make silken cocoons or burrow underground before forming pupae. Some skippers weave loose cocoons while others don't.

The least skipper has a wingspan of only _ inch (although even this is relatively large compared to one tropical moth with a wingspan of only 1/8 inch) and can be found throughout the eastern U.S. and Canada. It has a low, fluttery flight, and is usually found in tall grasses, often in ditches or other damp areas, where it feeds on nectar from the flowers of low growing plants. Females lay eggs singly on grass blades, the food plant for its light green miniscule caterpillars. I read that the last brood hibernates over the winter as caterpillars, but if the one I saw formed its pupa and then already hatched this spring, it got a very early start indeed.

Butterflies seem to be attracted to our gardens by seeing bright colored flowers but scientists have determined that they have very sophisticated senses of smell and taste, and these are what bring them rather than sight. Many of the receptors are on their antennae, segmented tubes moved by tiny inner muscles. These may be covered with minute hairs, knobs, bristles, or scales that are extremely sensitive to odors and chemicals, movements, physical contact, and even air humidity. The main functions are usually smell and taste, however, and butterflies often wave their antennae about as they "sniff" the air for telltale scents and odors. Insects need two antennae, incidentally, to establish direction. Tiny as they are, they can distinguish which is receiving the stronger scent and therefore can fly toward the source.

Butterflies rely on taste as well as smell and many of their taste receptors are located on their feet. Thus, a butterfly is led to a food source by the smell, lands upon it to taste with its feet and then probes with its feeding tube for confirmation. Observers have determined that the taste receptors in the feet trigger an increase in the butterfly's internal blood pressure causing the tube-shaped tongue to uncoil automatically.

Much as I enjoy seeing the first tiny butterflies, it is the arrival of the big swallowtails that convinces me that summer is really just around the corner. I saw a tiger swallowtail this week and am watching for a giant swallowtail, the black beauty with prominent yellow dots that form bands across its wings. This is a busy time here at the farm as we host weekend open houses this week and next. Bill, Cindy, Jim, and Catt will join me in welcoming you, so come see the wildflowers, the lumber operation, or just to walk the trails and visit our wild garden.

April 18, 2006

With so many fascinating things going on now that spring has definitely sprung, it is difficult to write about any one thing. Should I speculate about why the male kestrel (a falcon and one of the pair nesting in a ventilator hole in the side of our barn) persists in carrying around a very dead snakeor describe the unfamiliar miniscule butterfly that flitted around the drivewayor bemoan the numbers of Asian ladybugs that must be vacuumed each day from around the bedroom windowsor exclaim about the wild garden that is absolutely carpeted with bloodroot, hepatica and spring beautiesor tell about the frenetic activities of the treefrogs and toads?

Our most common treefrog, the spring peeper, measures little more than an inch in length, but it definitely makes up in sound for what it lacks in size. If you live anywhere close to a pond or wetland, you have undoubtedly heard its distinctive call, and when dozens are sounding off in chorus, it can be absolutely deafening. The call of a frog or toad is unique to its species. It is created by passing air through the larynx in the throat, and is amplified by an inflated vocal sac under the throat. Sound has a big advantage over sight in being able to produce signals over long distances. It can go around obstacles like trees so that it is very good in the forest, and it is effective both day and night. These calls convey lots of information, such as the species of the caller, as well as its sex and intentions, and presumably how desirable it would be as a mate. Peepers have a particularly piercing sound; in fact, one biologist measured one with peak amplitude at 110 decibels at a distance of fifty centimeters. Considering that sound pressure levels above 85 dB close to the source are considered harmful to the ear, it is fortunate that the treefrog call lasts only a second or two, although even then close proximity to a large population can cause pain.

This tiny amphibian, using its adhesive toe pads, can climb into trees and bushes, where it feeds mostly on soft-bodied insects, spiders and other small invertebrates. It can move very quickly, sometimes jumping over 17 times its own body length. It is very difficult to see in the daytime because of its size and protective coloring, but if you do happen upon one, you can distinguish it from other treefrogs by the prominent "X" on its back. The best way to find one is to go out at dusk with a flashlight and sit quietly by a pond until one calls close by. Even then, it requires patience to zero in on the sound, as it is difficult to track.

Researchers have identified at least two types of calls. Most common is the "advertisement" call, a single-note peep used to attract the attention of a female. The other is a trill, which warns other males to keep away. During mating the much smaller male typically grasps the female tightly from behind and releases his sperm directly onto the eggs as they are laid in the water. The female may lay up to 1,000 eggs, and they hatch into tadpoles, tiny fish-like creatures that lack legs, have gills for respiration, and tails with fins for swimming. Most fall prey to insects, turtles, snakes, or salamanders so all frogs tend to breed simultaneously, producing so many offspring that predators cannot take them all. The few that survive undergo a dramatic transformation. While the tadpole feeds entirely on tiny plant-life like algae, the adult frog eats mostly creatures such as worms and insects. Even the heart changes from the two-chambered organ typical of fish to a three-chambered one. At the end of two months, the tadpoles have developed legs, lost their gills and developed lungs. Their intestines have shorted as they shifted to a carnivorous diet, and their eyes moved closer together so as to give them the binocular vision they will need as predators. The final step was to reabsorb the tail.

The other easily identified call at the pond is that produced by the American toad. The male of this species emits a long, trill lasting 20-30 seconds and often, just before the first toad finishes, another will begin at a different pitch. The combination of toads and spring peepers creates quite a concert. This large (in contrast to the peeper), fat amphibian has a brown back and spotted belly, but its most distinctive characteristics are the wart-like protective glands on its back that produce a foul-smelling, toxic chemical which repels some predators. Even at that, raccoons have been seen to flip over a toad and eat it from the underside to avoid the glands, while hog-nose snakes simply swallow the toads whole, evidently ignoring the taste.

Now that I have focused the activities of the noisy peepers and toads, there is only a bit of space left to touch on the other topics mentioned at the beginning of this article. I have no explanation for the kestrel and the snake, except that perhaps his mate declined it as a gift and he is having a hard time finishing it off by himself. We will continue to vacuum up ladybugs, and you can see the flowers, and perhaps the butterfly, for yourself if you come visit our open houses that will be held on April 29-30 and May 6-7. We'll be happy to see you again.

April 11, 2006

There is a pink cast to some of the trees on the hillside across from the house these mornings, but it is necessary to get closer to see that it comes from tiny scarlet flowers on the red maples. Everyone knows that fruit trees as well as redbud, dogwood, and magnolia trees have blossoms, and we often plant them in our yards so that we can enjoy their beauty in the spring. What many people do not realize is that our forest trees also produce flowers; in fact, if they didn't, they could not produce seeds. Some kinds, such as the elms and maples, bloom profusely but the flowers are so small and often delicately tinted so that they are seldom noticed. Others, such as the poplars, oaks and walnuts, have peculiar flowers in the form of catkins that, without petals or sepals, do not look like flowers at all.

The flower is the reproductive unit of our more advanced plants. Each must have a pistil, the female reproductive organ, and may also have stamens (the male reproductive organs that produce pollen), petals, and sepals. The pistil must have at least one stigma, style and ovary and may have more. At the top is the stigma, a special tissue that can receive the male pollen grains. After the pollen grains land on the stigma, either blown by the wind or carried by an insect or animal, pollen tubes grow down through the style to the ovary carrying the sperm. The ovary produces reproductive cells called ovules, which when fertilized by the sperm become the seeds.

Some flowers have both male and female reproductive organs and are called "perfect" flowers; others have only one or the other and so are either male or female flowers. Some plants have both kinds of flowers, while others have males on one plant and females on another. Elms have small greenish "perfect" flowers, while walnuts have separate male and female flowers on the same tree.

A birch tree also has both male and female flowers. Birches can begin flowering when they are as young as five years old, and the flowers appear in the spring at the same time as the new leaves. The male flowers are drooping catkins, while the female flowers are upright. Pollination is by wind, but then the female flowers ripen to form hanging catkins in late summer that contain hundreds of tiny winged seeds. A large tree can produce up to 1 million seeds in a year, but only a few of these will germinate and grow into mature trees. The majority of seedling trees become established close to their parents, but some seeds can travel long distances on the wind.

Oak trees have male flowers on one part of their branch, and female flowers on another part of the same branch, but you have to look closely to see the female flowers. They might be taken for buds but are actually reddish 3-lobed stigmas. Below each there is an egg-shaped camouflaged ovary that becomes the acorn. The male catkins are yellow, wormlike things and once the stamens have released their pollen into the air, the entire catkin will fall from the tree, littering the ground. A great oak may be so covered with clusters of tassel-like catkins that its entire crown has a yellowish or reddish tone.

An aspen tree may be either all male or all female. Trees flower in March and April, before the leaves appear, with both the male and female trees producing catkins. Pollinated female catkins ripen in early summer and release tiny seeds each weighing about one ten-thousandth of a gram, which are tufted with hairs. Willows and other poplars, boxelder, and mulberry bear the male and female flowers on separate trees. To confuse the issue further, there are also species which have not only have "perfect" flowers but, also, on the same tree, either male or female flowers or both.

Most trees are wind-pollinated and so their flowers have no need for any petals or sepals to attract insects. After discharging their pollen, the male flowers wither and soon disappear. Other trees, however, are pollinated by insects, and must have attractive flowers. These may have bright colors, large size, or ultraviolet patches, and some trees like the black locust and the linden, are so fragrant and laden with nectar that they attract swarms of honeybees. Each kind of tree has its own time for blooming. Silver and red maples, elms, cottonwood, aspen and the redbud bloom in early spring, long before their leaves appear. Many trees bloom shortly after their leaves unfold like the oaks and hickories. The catalpa and linden and bloom last, in June, long after their leaves are fully developed.

Meanwhile, beneath the trees, the first wildflowers are appearing. Spring beauties have opened their first blossoms, and hepatica and bloodroot will be close behind. We are approaching the loveliest time of the year.

I climbed the hill above the barn a few days ago, headed for the bits of native prairie that still contain a small population of pasque flowers. These areas were never cultivated during all the farm's years as a dairy operation and it would seem that the close cropping given them by generations of browsing cows benefited the flowers that grew there, perhaps because the thick grass cover was kept in check. For whatever reason, now that the fields are no longer grazed, these relatively rare wildflowers are becoming more and more scarce, and the few that do show themselves are often gobbled up by passing deer. Still, each springtime finds me crawling around up there on my hands and knees, clearing away the matted grass and leaves in search of the first fuzzy buds.

The French reportedly named this plant passefleur or pasque flower because it blooms about the time of Passover (Pesach) and Easter, and that name has persisted. It has two-inch lavender blossoms that bloom before the leaves appear, each composed of five to seven petal-like sepals that enclose the flower parts. Petals are usually the showy part of a flower while sepals are usually green and inconspicuous, but in the case of pasque flowers and other members of the anemone family, the petals are absent and sepals take their places, although it has never been clear to me how botanists determine what is which. I read that at one time, the blossoms were dried and powdered, and were thought to be useful in treating eye diseases like cataracts, which is a clouding of the lens of the eye leading to blindness.

White silky hairs densely cover all parts of the pasque flower giving the plant its fuzzy appearance. When the blossom fades, the deeply cut, lacy leaves expand and the flowering stalk stretches up, displaying a large head of conspicuous seed plumes. Each silvery feathery wisp is attached to a small dry one-seeded fruit that is carried off by the wind. At this stage, the plumed pasque flower resembles another prairie resident, prairie smoke, but the two species are unrelated.

The pasque flower is especially interesting because it has a caudex, a thickened section of its stem just below the soil level from which each year's growth emerges. Perennial plants have developed a variety of strategies for survival through inclement weather. Some have tubers such as potatoes that are technically modified underground stems that act as storage organs. Others have bulbs, which are upright underground stems surrounded by overlapping, fleshy scales. Still others have corms, solid underground stems without scales. The difference between these stratagems and the caudex is that they are primarily concerned with storing food, while the caudex is mainly a water storage adaptation and is found in many desert and prairie plants. Plants so equipped can store moisture and survive many months of hot, dry conditions.

I found no emerging pasque buds on this week's visit, but did uncover a birdsfoot violet hiding beneath a clump of grass. The dark purple flower of this tiny plant is about an inch wide and looks something like a pansy, with a flattened face and three lower petals a light blue color. Its leaves are cut into narrow segments and look something like the foot of a bird, giving rise to both the common and species name. Farther south, this plant is said to be evergreen, with its foliage persisting over the winter, and I wonder if that is the case here as well, as the rosette of leaves is well developed for a new growth. In any case, it will be in bloom shortly after the pasque flower, and I'll make sure to visit it again before it fades. Its tiny, copper-colored seeds will be ripe in about a month and are contained in smooth green capsules. When the capsules open, the seeds are catapulted up to five feet away from the parent plant, while ants also assist seed dispersal by carrying seeds back to their nest.

The bird's-foot violet occurs in scattered populations in eastern North America north of Florida, from southwestern Ontario (where it is considered a threatened species) and northern New England west to Iowa and Kansas. It prefers savanna conditions and produces a short, vertical rhizome and a few fine roots off of this main stem. Like all violets, it's a cool season plant, growing best during the cool, moist weather of late winter.

Woodland plants are more protected from springtime storms and are more advanced than those of the prairie. Spring beauty and hepatica buds are showing color, and Virginia bluebell and bloodroot sprouts are pushing up through the leaves. Every day brings something new springing green.