“Our fellowship with other creatures is real, our union with the creation is already achieved, because we all rise and fall on a single breath. You and I and the black-footed ferret, the Earth, the sun, and the far-flung galaxies are dust motes whirling in the same great wind…Wherever it flows–in person or place, in animal or plant or the whole of nature–we feel the pressure of the sacred, and that alone deserves our devotion.”
–Scott Russell Sanders, Earth Works (2012)
I have yet to meet the gardener who would not stop digging to watch a butterfly float over the garden fence, alighting on a near blossom to nectar. Here in midcoast Maine, where bleak winter is nearly six months long, the first butterfly of spring is a true harbinger of the long gardening days ahead, as good a reason for celebration as I can imagine.
Butterfly watching is an integral part of gardening for many of us. We delight in watching them sip nectar from the flowers of plants that we grew expressly for their use, and we strive to learn the name of each species, often a daunting task. I am still laboring over photographs of different fritillaries taken in past years, wading through field guide images of similar species, trying to pin down the identity of each unknown.
Adult butterflies are conspicuous incidental pollinators. They survive entirely on nectar which they sip with long tongues, often avoiding contact with the flower’s pollen-loaded anthers. Nevertheless, they do accidentally move enough pollen around to contribute to plant reproduction.
Stages in the life history of the monarch butterfly (Danaus plexippus) serve as a general model for the life cycle of most butterflies: egg, larva, pupa, adult. Eggs are laid on or near a preferred host plant, a milkweed in the case of monarchs. From each monarch egg hatches a tiny black-, white-, and yellow-banded caterpillar that feeds voraciously on the host plant for about two weeks, growing longer and fatter each day, until it transforms into a pupa encased in a chrysalis. It is during this pupal stage, also about two weeks in duration for the monarch, that the amazing transformation to a winged adult takes place.
There are, of course, variations in the timing of each stage. The monarch, the best known of the migratory butterflies, overwinters as an adult in the oyamel fir forests of Mexico before embarking on a multi-generational trek, laying eggs on milkweeds as they travel north and east. A handful of other species overwinter as adults in areas of the country with frigid winters, holding up in the cracks and crevices of rocks and trees. This group includes the mourning cloak (Nymphalis antiopa), Eastern comma (Polygonia comma), green comma (P. faunus), question mark (P. interrogationis), and the Milbert’s tortoiseshell (Aglais milberti). Across the country, these are the first butterflies of spring, the first caterpillars to feast on new foliage. Wherever you live in the U. S., a walk in the winter woods is likely to bring you close to one or more of these species.
Red admiral butterflies (Vanessa atalanta) also migrate, moving northward from overwintering areas of the deep south (North Carolina southward) to appear in Massachusetts during the first week of May, later in more northern locations. I’ve noticed that the wings of early arrivals are often tattered, an indicator of their long northward trek. Adults from spring matings in northern areas begin to appear in mid-summer and repeat the reproductive cycle to produce a third generation of adults seen from late August to October. Some individual butterflies from this third generation migrate south as temperatures drop.
Nettles, including stinging nettle (Urtica dioica) and false nettle (Boehmeria cylindrica) are the larval host plants for red admirals. In our garden we have seen adult red admirals nectaring on a variety of flowering plants, including spring dandelions, chives, and late summer goldenrod.
One of the most beautiful butterflies to grace our garden each summer is the white admiral (Limenitis arthemis), named for the broad white median bands on its black wings, the hindwing marked with a marginal row of blue dashes and a submarginal row of red dots. The reddish-brown undersides of the wings are painted with the same white median bands. (There is another form of this same species called the red-spotted purple butterfly and the two variants hybridize where their ranges overlap.)
The list of larval host plants for white admirals includes many of the tree species that surround Marjorie’s Garden, including red oaks, yellow birches, willows, aspens, and serviceberries. The adults feed on sap flow, rotting fruit – we often see them foraging on overripe blueberries, aphid honeydew, and the nectar from small white flowers, including spireas, privets, viburnums, and summersweet clethra. It is a pink form of Clethra alnifolia that keeps them in our garden through the summer.
The white admiral survives the winter as a small immature caterpillar enclosed within a leafy shelter on one of its preferred host trees. The larva chooses the leaf that will be its winter home in late summer, firmly attaching it to a twig with threads of silk to keep it from falling off the tree in autumn. When ready to pupate, the inch-long caterpillar aligns itself with the midrib of the leaf blade, chews off the end and most of the sides of the leaf, then pulls what remains around its body, forming a small tube held together with more threads of silk. The young larva sleeps through the winter in its leafy cocoon, protected from subzero temperatures by remaining in a state of deep diapause, completing its larval growth in spring.
The eastern tiger swallowtail (Papilio glaucus), easily recognized by its bright yellow wings, the forewings marked with four black “tiger stripes”, is a regular visitor to Marjorie’s Garden, drawn there by pots of annual blue lobelia (Lobelia erinus) scattered about the garden. Males have a few orange and blue spots near the tail while females have more blue on the hind wing.
Female tiger swallowtails can occur in two forms, yellow, like the males, and a dark form with the blue spots but no yellow. The dark form mimics another butterfly, the pipevine swallowtail, which has a very disagreeable taste and thus is shunned by most predators. Where populations of tiger swallowtails and pipevine swallowtails coexist, a portion of the the female tiger swallowtails will have the dark coloration and thus avoid predation.
Favorite larval host plants of eastern tiger swallowtails include tulip poplars (Liriodendron tulipifera), sweet bay magnolia (Magnolia virginiana), willows (Salix spp.), American hornbeam (Carpinus caroliniana), red maple (Acer rubrum), spicebush (Lindera benzoin), American elm (Ulmus americana), sassafras (Sassafras albidum), and black cherry (Prunus serotina).
Eastern tiger swallowtails can often be seen “puddling”, young males congregating in large groups on mud, damp gravel, or puddles to extract sodium ions and essential amino acids. Solitary females also engage in this activity.
Growing annual flowering plants, such as cosmos and zinnias, either in beds or in pots, can greatly enhance the variety of butterflies that visit you garden each summer. As mentioned earlier, the blue lobelia, L. erinus, has proven to be a magnet for eastern tiger swallowtails, fritillaries, and silver-spotted skipper, as well as bees, in our garden. Our recommendations for perennial plants that attract butterflies would include the aforementioned summersweet clethra, goldenrod (Solidago spp.), swamp milkweed (Asclepias incarnata), and purple coneflower (Echinacea purpurea).
In all their diversity of sizes, colors, and life histories, butterflies, both the adults and their caterpillars, add a dimension of wildness to the garden, a sense of wonder. They are indeed part of a sacred world that deserves our devotion.