SCOTT SHALAWAY Milkweed is a butterfly magnet

In about a week the butterfly milkweed in the hayfield will burst into bloom. Widely scattered in patches across the four-acre meadow, my favorite native wildflower splashes splotches of evening sun from one end of the field to the other.
As its name implies, brilliantly orange butterfly milkweed (Asclepias tuberosa) is a butterfly magnet. Monarchs, in particular, seek out milkweed of all species. Females lay their eggs on milkweed leaves, and after hatching, the caterpillars devour the leaves, which are toxic to most herbivores. The bodies of both larval and adult monarchs retain remnants of the toxic compounds in their bodies. Consequently, predators, particularly winged ones, avoid monarchs.
But butterfly milkweed flowers attract a variety of butterflies. Many species, large and small, nectar at its flowers and add to its appeal as a backyard wildflower. Just watch a field of blooming milkweed to confirm this point .
I try to get up to the hayfield at least several times each week. Yellow-breasted chats, prairie warblers, and blue-winged-warblers sing from perches around the perimeter of the field, and a pair of bluebirds owns a nest box at each end of the field. Deer often spend the night in the high grass that remains unmowed along my trails. In the hayfield, there's always something interesting to watch.
Blossoms were alive
One spring, as I approached a large patch of the colorful milkweed, the blossoms seemed alive. They seemed in motion. I glassed them with binoculars and discovered scores of butterflies single mindedly sipping nectar from the flowers. I've often seen butterflies nectaring on milkweed, but nothing like this. I've never seen such a concentration of butterflies. Curiously, none were monarchs.
Most were fritillaries. Fritillaries are medium to large orange butterflies. The upper surfaces of their wings are marked with black dots, dashes, and crescents. From a distance they blend into the milkweed's flower head. That's why the flowers seemed to move. It was the flutter of the fritillaries as they perched atop the orange wells of nectar.
The largest fritillaries had wingspans of about three inches. I identified them as great spangled fritillaries. Others were smaller, with wingspans of approximately two inches. These, I concluded, were meadow fritillaries. Regardless of their specific identity, they were definitely fritillaries of some sort. And there were hundreds of them.
As I moved from one patch of milkweed to another, I discovered each was crawling with butterflies. The vast majority were fritillaries, with a few tiger swallowtails thrown in for variety.
Native butterfly garden
It was a spectacular, native butterfly garden. I had encouraged it by allowing the elongate pods to go to seed each fall, but these beautiful wildflowers colonized that hayfield decades ago after the ridge was first logged. I've taken advantage of this population of butterfly milkweed by moving a few plants each year from the hayfield to beds around the house. The resultant scattered patches of milkweed in the side and back yards now also attracts butterflies.
That fritillaries are so common comes as no surprise. Their larval host plants are violets, small flowers that grow wild in many lawns. Though the summer flight of the fritillaries has begun, females delay egg-laying until August. At that time, they lay single eggs on or near violet plants. After hatching, the tiny caterpillars crawl into the leaf litter and go dormant until spring. When they re-emerge in April, they eat the young violet leaves, and ultimately transform into adults in June.
Endure caterpillars
Most butterflies eat only certain plants as caterpillars. This is the most important lesson in butterfly conservation. If you want butterflies, you must endure the caterpillars. Without food for caterpillars, the best we can hope for is an occasional butterfly fluttering by.
If you need help identifying backyard butterflies, I recommend a new field guide entitled Butterflies of North America by Jim Brock and Kenn Kaufman (2003; $22.00; Houghton Mifflin). More than 2,200 images, detailed range maps, and informative text, including larval food plants, vault this pocket-sized book to the top of the list of butterfly field guides.
sshalaway@aol.com