(journal)

Swamp Muse

A seasoned Louisiana naturalist discovers a thing or two about a rare butterfly as he explores a drought-stricken wetlands near his home.

By Gary Noel Ross

 

 

Wednesday, May 31, 2000. The Bluebonnet Swamp Nature Center is now dry, according to headlines in The Advocate, the Baton Rouge newspaper. The popular urban nature preserve is described as another victim of the South’s record-setting drought. The color photographs depict inconsonance: Portly bald cypress and tupelo gum trees, stalwarts of quiet, tannic swamps in the Deep South, now were anchored in inky muck fractured into mini polygons.

I am alarmed. Just three weeks prior, a friend, Robert Sherman, and I had discovered within the swampy domain a small cadre of a rarely encountered and poorly understood butterfly. This lepidopteran, the Seminole crescent, is barely an inch across but quite debonair: daintily scalloped wings, dark brown except near the body, where there is a blush of orange-red—all accented with small, creamy-colored squares and crescents. Having spent much of my life prying into the private lives of butterflies, I knew that crescents are the quintessential butterflies of the proverbial Elysian Fields. But this spooky swamp? Smitten, I vow to embark upon a new research project.

Sunday, June 4. I hustle to the nearby swampland. The paper had been right on target—nary a puddle in sight. The vegetation is yellowing, and the air is hot, dry, and mute—like the Biblical “scourge upon the land.” Yet several Seminoles are flying; serendipitously, I am privy to a female laying eggs on a small plant growing at what was once the water’s edge. I snip a plant for later identification. After a few hours I depart to check three smaller satellite sinks within the same drainage basin. Drought prevails there, too, but a handful of Seminoles are flying.

Standard field guides offer scant information on the Seminole crescent. Classified as Anthanassa (Phyciodes) texana seminole,the insect is considered a close relative of the Texan crescent, A. (P.) texana texana. Still, the taxonomy is by no means settled. Some butterfly mavens, for instance, have suggested that the two forms are separate species. Regardless, it is easy to tell them apart—the orangey wing splashes in Seminoles are smaller in Texans. And while the latter is common throughout the American Southwest, Mexico, and Guatemala, the Seminole form occurs in only a few scattered localities in Louisiana, Florida, Georgia, and South Carolina. The field guides further note that Seminoles prefer small watercourses, and Texans, dry gulches.

I identify the host as looseflower water-willow (Justicia ovata Lindauvar. lanceolata), a northern member of a predominantly tropical family: Acanthaceae. The species is a semiaquatic colonizer of bare flood-prone earth. Individual plants are short and shallow-rooted, and form a radial pattern of growth. Leaves are narrow, dark green, and glossy; blooms are single, small, lavender, and perched on a thin spike between leaf and stem. That Seminoles are using water-willow makes sense: Researchers record the acanthus family as the exclusive host for the Texan crescent.

With the entire venue dry, I can sleuth the bottomlands. As I walk, an odor—musty, organic—wafts into my nostrils. Amazingly, water-willows exhibit exuberant nascent growth.

Monday, June 5. I return to the beleaguered sanctuary. Elevated boardwalks and stone-bed trails wind through the scant 101-acre preserve, which is encapsulated by an ever-increasing number of upscale residential and commercial sites. Only two-thirds of the enigmatic preserve is ever under water. Now, with the entire venue dry, I can sleuth the bottomlands. As I walk, an odor—musty, organic—wafts into my nostrils. Amazingly, water-willows exhibit exuberant nascent growth, creating splashes of vivid emerald on the crackled earthen canvas. From the corner of my eye I detect a flash of telltale, luminous orange. My head swivels and I log my first Seminole. By noon I have tallied 45 individuals. The Seminole’s milieu is compatible with the greatest concentrations of host plants—the border between normal water level and terra firma. Today the little hot shots seem cavalier, as if they can grasp that this windfall of savory hosts portends bumper families. I, too, am fettered to the moment.

 

During the next few weeks I tackled Seminole Biology 101. At about 9:30 a.m. a male will leave his nightly perch on low vegetation and fly to a low, sun-dappled leaf or even the boardwalk, to bask. He spreads his wings to harvest all the candlepower the filtered rays can muster. By mid-morning males begin patrolling low to the ground in search of virgin females. When a damsel is sighted, the Romeo woos by, looping about her. Often the twosome pirouette upward. If the female is receptive, she will return to ground level to settle onto a leaf to display by opening and quivering her wings. The male postures alongside, and after a few probes with his abdomen, the couple turn in opposite directions and interlock abdomens. And that’s that.

A pregnant female will bask, too. However, she spends much of the late morning and early afternoon searching—almost in slow motion—for water-willows. When satisfied, she alights and closes her wings. For the seminole, egg laying has a decided finesse. The female begins by backing up to an edge of the leaf. She then extends and arches her bloated abdomen beneath the leaf as she quickly extrudes and glues a tiny yellow egg. Her abdomen sweeps from side to side, releasing an egg roughly every four to six seconds, creating a compact row. The breadth of each arc is determined by simple mechanics. Thus the number of eggs per row varies: Early and late rows have fewer eggs; middle rows, the most. The result is a circular cluster. Once I observed a female deposit 145 eggs during an uninterrupted 31-minute session. If disturbed, the female flares off to home in on another suitable leaf. Since a female can bear upwards of 300 eggs from her single mating, she may generate four to six small clutches during her lifespan of barely three weeks.

After five days the eggs hatch synchronously into tiny caterpillars, or larvae. At first the peewees sport four rows of short spines and are transparent, except for their heads, which are a glossy jet-black. The caterpillars soon appear to turn green, but this is due to leaf mash in a distended gut and the Seminoles’ “see-through” bodies. The larvae are social, remaining within their tightly packed cluster. (My mind’s eye conjures a slice of kiwi fruit.) The caterpillars are tidy, munching on the leaf’s spongy undersurface tissues and avoiding the tough internal infrastructures. Within two days the leaf resembles fine lace—a discriminating marker for Seminoles. If disturbed, youngsters curl up en masse, drop to the ground, and feign death. After 10 to 20 minutes the tiny “possums” inch their way back up their host and resume business as usual.

The appetites of caterpillars operate in overdrive. Such gluttony dictates that crawlers must exchange their skins (molt) every few days. Following its first molt, a Seminole caterpillar dons an attire that is opaque black with tan sides and bottom. A couture of black, plumose spines completes the ensemble. The prickles, though, are only a bluff.

Seminole young produce a green “goo,” which they regurgitate when disturbed and excrete in their frass—a.k.a., caterpillar poop. While researching the acanthus family of plants, I have learned that at least six species contain phytochemicals—that is, complex compounds that have no direct metabolic involvement but exhibit specific biological properties in the laboratory. Because no raison d’être is offered for these bonus chemicals in acanthus, I bravely taste the goo. Pungent, like the proverbial “cup of bile”! Therefore, here is my take: Seminole caterpillars may sequester phytochemicals from their host, creating a defense potion to spurn a potential nemesis—perhaps even a microbe endemic to dingy, quaggy habitats.
 
Older caterpillars are less social, dispersing to other water-willows, where they consume all but the tough veins of the leaves. After approximately three weeks a caterpillar will crawl to a tree trunk or bush, to a spot a foot or so above normal water level, to metamorphose into a chrysalis, or pupa. At this point, the Seminole is a mottled dark brown with small tubercles, and resembles a dead leaf. After about a week, a new life-form emerges. (Seminoles produce three to five generations each year but pass the winter as a chrysalis.)

Seminoles and their hosts yo-yo in concert astride an ecological tightrope; that is, while a Seminole colony is dependent upon a watery landscape, too much or too little water can be a curse.

 

My unencumbered access to the waterless swamp provided other insights. Take predation. Having reared several Seminoles in a makeshift home laboratory, I knew that the body and legs of a fresh butterfly are clad with tiny, easily shed scales. Puzzling. Then one day I happened upon a fresh female Seminole as she blundered into the gossamer threads of an orb weaver spider—a stealthy vixen common in southern swamps. The butterfly bounced out, like a kid on a trampoline. I never expected to see a snagged Seminole, although I did observe two other types of butterflies cocooned as silken larders. As a result, I advocate that the deciduous scales clothing a fresh Seminole empower the insect as a quick escape artist.

Next, food. I was constantly puzzled by a disconcerting observation: The butterflies didn’t appear to feed. Now, experience has taught me that a typical butterfly day centers on a search for food, principally high-octane flower nectar. Alas, the swampy part of the sanctuary was remarkably flower-free. I assumed that the butterflies were on occasion sallying out of the wet oasis to dine on top-dollar banquets in the nearby sunny, manmade landscapes. But my surveys proved negative.

Then, an epiphany. Late one afternoon my attention was piqued by two female Seminoles. They were walking while probing the ground with their uncoiled proboscises. I dropped to my knees and began crawling with bated breath toward the errant butterflies. Could they be “puddling”? (In this behavior, male butterflies gather on damp soil to siphon minerals from which they synthesize semen.) But females, and on dry ground? Obviously, this was no social club. Each butterfly was patently attracted to a bluish-green crust on the parched earth. Turns out that these Pillsbury biscuit–like flakes are cyanobacteria, single-celled organisms that often form films on damp earth. (The butterflies most likely liquefy the microbiotic matter with saliva.) During the next hour I spied two other females and two males behaving in the same manner. Eureka! The Seminole crescent is a rebel, and I had discovered something new in the world of butterflies.

But things are not always as they seem. Two days after my revelation, Robert telephoned to say that when he was in his hummingbird–butterfly garden the afternoon before, he witnessed a female Seminole nectaring on a lantana and laying eggs on two ornamental acanthus: king’s crown and shrimp plant. Was this happenstance with a maverick butterfly? I immediately searched the wildlife-friendly gardens of my friends. Surprisingly, I uncovered six locations (fortuitously, one is my personal garden!) hosting adult or larval Seminoles; the neighborhoods are leafy and—as the crow flies—no more than three or four miles from the Bluebonnet sanctuary. Therefore, I conclude that while A. t. seminole may call home a swamp, the butterfly retains vestiges of its past and so is capable of exploiting suitable urban settings to fulfill its biological imperatives.

Sunday, July 9. The dry weather has deepened. On this afternoon the swamp is cursed by another plague—this time, ironically, water. The Thunderstorm from Hell has roared in, venting nearly three inches of rain within one hour. When calm returns, I rush with foreboding to the swamp. The construction sites nearby have channeled water into the sanctuary at breakneck speed, in effect flushing out small ground dwellers. A solitary female Seminole flits above a submerged boardwalk, like a refugee defiantly returning to ground zero.

Monday, July 17. I revisit the swamp. The air is dank and abuzz with mosquitoes—plankton of the air. The water has dropped to wading level. I suit up and ease into the languishing liquid, tepid and tea-colored because of its cargo of silt. I quickly sink into the gumbo, but the water levels off just below my knees. The maelstrom has proven an elixir for the ailing ecosystem. Many plants are budding. Many of the crucial water-willows, however, are still underwater, while others are coated with silt. Worse, the flood has stripped the plants of their precious caterpillars. I uncover only one cache of 76 eggs, though they are coated with silt. I collect the leaf to take home.

 

For the remainder of the season I revisited the swamp weekly. I observed no adult Seminoles. (The eggs I had collected were nonviable; presumably the silt had delivered the coup de grace.) Residential gardens were another story; there I observed a few Seminole adults visiting flowers and spawning new generations on landscape acanthus.

My lure for Seminoles continued into 2001 and 2002. In 2001 tropical storm Allison walloped the northwestern Gulf Coast, dropping nearly 20 inches of rain on Baton Rouge. Surrounding wetlands were inundated, and I failed to locate a single Seminole. In contrast, I did locate a handful of caterpillars in local gardens. Spring 2002 experienced three ominous torrents; during September and October, two juggernauts, tropical storm Isidore and hurricane Lili, pummeled Baton Rouge with more than 15 inches of rain. With the floodgates open, Seminoles, of course, hadn’t a chance. I ferreted out only 16 larvae for the year—all within a single garden.

Reflecting upon my three-year odyssey, I realize that many questions remain unanswered. This, however, I do know: A. t. seminole is geographically, ecologically, and behaviorally distinct from A. t. texana. Regrettably, Seminoles in Louisiana are now in serious trouble. The state’s interior wetlands, once considered worthless, are now being drained at unprecedented rates by high-rolling developers, driven by avarice and sanctioned by government. Such pillage produces a checkerboard landscape increasingly vulnerable to oscillations of weather. In a literal sense, Seminoles and their hosts yo-yo in concert astride an ecological tightrope; that is, while a Seminole colony is dependent upon a watery landscape, too much or too little water can be a curse.

And that does not take into account the impact that hurricanes Katrina and Rita, which devastated southern Louisiana in 2005, will have. Certainly all of the Seminoles’ habitats have been affected. For example, most habitats now will experience increased illumination due to massive tree fall, and that could encourage the spread of the host plant, thus benefiting butterflies. On the other hand, tree fall has severely altered drainage patterns, so many habitats will become excessively wet or dry, thus discouraging Seminoles. Obviously, predictions are nearly impossible. However, this is certain: Today a Seminole colony can be nothing more than a flash in the pan.

Yet the future of my “swamp muse” does not have to be doom and gloom. It seems to me that the Seminole crescent could be embraced as a metaphor for healthy wetlands. The razzle-dazzle of celebrity billing could inspire a truce between developers, governmental agencies, and conservationists. Upping the ante, wildlife-savvy homeowners could rally to retool their gardens with ornamental acanthus, thus providing urban mini sanctuaries for the opportunistic butterflies. Given half a chance, this small butterfly just might capture the hearts of Baton Rougeans the way a charismatic red-tailed hawk named Pale Male did in Manhattan. l

Gary Noel Ross is a research associate at the McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, in Gainesville, and director of butterfly festivals for the North American Butterfly Association (www.naba.org). He won a John Burroughs Award of Recognition for the best essay in natural history for 1995.
 

 

 

© 2006 National Audubon Society

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