Content provided in partnership with
Diana's mountain retreat: named for the Roman goddess of woodlands, a singular butterfly survives in a shrinking habitat
Natural History, March, 2008 by Gary Noel Ross
[ILLUSTRATION OMITTED]
July 4, 1992, 5:30 P.M.: My pickup truck is parked off a lonely Forest Service road that loops around the rim of Mount Magazine, a loaf-shaped peak in Arkansas. Peering over the steering wheel, I have a panoramic view of a long valley 2,000 feet below, but my attention is focused on the nearby wildflowers. In front of me, bordered by patchy, stunted forest, is a small meadow yellow with coreopsis flowers, and off to the side, within a bright gap in the trees, purple coneflowers advertise themselves with droopy whorls of pink petals and yellow-orange pincushion centers. I've been holding vigil here since midday, hoping to spot a medium-size butterfly known as the Diana fritillary (Speyeria diana). So far I've counted nine species of butterflies, but no Dianas.
- Most Popular Articles in Reference
- The importance of understanding organizational culture
- Credit card attitudes and behaviors of college students
- What factors attract foreign direct investment?
- Libraries Need Relationship Marketing - mutual interest marketing concept, ...
- How to set performance goals: employee reviews are more than annual critiques
- More »
Then I realize a new butterfly has appeared atop one of the coneflowers. Its black and light-blue wings show it to be a female Diana. I grab my binoculars and watch as she walks slowly on the flower's spiky center, probing into the crevices to access the minute reservoirs of nectar. Occasionally she flies upward a few feet, circles the small patch of coneflowers two or three times, then resettles to resume feeding.
Past experience has taught me that temperate-zone butterflies depend upon warmth from the sun for flight energy and usually cease feeding long before the sun sets. But as one hour passes, then another, my Diana shows no sign of retiring. The sun sinks toward the western horizon and deep indigo tones advance from the east, but still she concentrates on her sugar fix. Fireflies begin to flicker in the darkness. My eyes are so tired and the light is so faded that I have difficulty discerning the Diana's dark silhouette.
Finally at 8:50 P.M., the butterfly launches straight up and alights upside down on a yellowing leaf of a nearby hickory tree. With her wings now closed, the dark brown of their underside is revealed. After a few seconds she tucks her two forewings partly into her hind-wings. The overall effect is that of a frayed, dead leaf. I keep watch for another ten minutes to make sure she has indeed settled in. Then I retreat into the camper in the bed of my pickup, quickly down two cans of Ensure--my usual evening meal when in the field--and fall into my own nocturnal slumber.
The S.diana is the largest of some fourteen species in a genus of butterflies commonly referred to as the greater fritillaries. Members of the genus typically sport a checkerboard pattern of black spots on their wings--their name "fritillary" is from the Latin word for "dice box"--against an orangey background; the undersides of their wings are brown with silvery spots. In most species the males and females look similar, but the females are characteristically larger. All live in regions with cold winters and snowfall. The males emerge from their pupal stage (chrysalis) in early summer, usually a few weeks before the females, and die within two to three weeks after mating. The females, however, live for three or four months, and lay between 1,000 and 2,000 eggs during a three- to four-week period in the autumn.
That is an extraordinary number of eggs for a butterfly, a hint that the greater fritillaries must compensate for some hurdles in their life cycles. The eggs are deposited singly on ground litter, not on plants upon which the larvae, or caterpillars, can feed; violets, their host plants of choice, are usually desiccated by that time. Although the larvae hatch in late autumn and partly consume their egg casings, they do not feed on vegetation--instead they hibernate in the ground litter throughout the winter. In the spring, however, with the fresh growth of violets, the young caterpillars emerge and start munching away on the foliage.
Some of these features, such as the overwintering of very young larvae, are unusual for butterflies. Even among the cold-friendly fritillaries, however, the Diana is unusual, beginning with its coloration, which--atypically for fritillaries--is different in males and females. The upper surfaces of a female's wings are black with pale blue splashes and dots; the undersurfaces are a rich mottled mahogany color. By contrast, male wings are dark brown with extensive orange outer margins on top, while below they are a dull cinnamon color. And whereas most fritillaries are at home in sunlit meadows, Dianas are partial to heavily forested habitats (in Roman mythology, Diana was the goddess of woodlands, childbirth, and fertility).
[ILLUSTRATION OMITTED]
First named in 1775 from specimens in Jamestown, Virginia, the species was historically common throughout the temperate deciduous forests of the southern Appalachian Mountains and westward to the Ozark-Ouachita Mountains of the Midwest. Presumably it once had a continuous range, but in Butterflies East of the Great Plains, published in 1984, Paul Opler and George Krizek recorded four separate populations. Two of those, they noted, had already disappeared:
Find Research Guides for:
Most Popular Articles in Reference
- The importance of understanding organizational culture
- Credit card attitudes and behaviors of college students
- What factors attract foreign direct investment?
- Libraries Need Relationship Marketing - mutual interest marketing concept, ...
- How to set performance goals: employee reviews are more than annual critiques
- More »