On the Trail of the Black Petaltail
By: Daniel Newberry, Jefferson Public Radio
October 10, 2011
The state of Jefferson is home to one of the oldest species on earth, yet relatively little is known about it. The black petaltail dragonfly (Tanypteryx hageni) is a member of a dragonfly family that predated the dinosaurs. This enigmatic and rare insect has a narrow black body slightly more than two inches in length, with yellow dots on its head and body. It is found as far south as the coastal mountains in Sonoma County, California, inland to Yosemite National Park. Its northern range extends to British Columbia.
Sit quietly on a vegetated bank of almost any pond or wet area during the hottest part of a sunny summer day, and a host of dragonflies are likely to reveal themselves. They soar and swoop, dip and jerk at incredible angles, smack the water to grab an insect, and even rise vertically like a helicopter.
Dragonflies resemble their cousins, the damselflies. The easiest way to tell the two apart is that dragonflies have two sets of wings that they hold perpendicular from their bodies, even at rest, while damselflies, hold their wings together—or slightly open—above the torso. Dragonflies pick off their flying-insect prey in mid-flight, while damselflies pick their crawling-insect prey off vegetation. With these varied diets, both dragonflies and damselflies coexist in their separate niches. More likely than not, you’ll see several species of both in the same location.
“We have 50 species of dragonflies and 25 of damselflies in the state of Jefferson,” says Kathy Biggs, author of the field guide, Common Dragonflies of California. Biggs divides her time between McCloud and Sebastopol, California.
“One of the reasons we have so many is the diversity of habitats,” Biggs explains. “We have the coast all the way to high elevation mountains, like Shasta, to the desert highlands.”
The path to dragonfly study began for Biggs when she built a pond in her back yard. “The minute I did, they showed up. Being a birder, I’m used to listing them, and I couldn’t list them because there weren’t any guides.” Biggs promptly researched the critters she observed as best she could, and created her own dragonfly website.
Without guides, few non-scientists were out identifying species when Biggs got started. The relative abundance or rarity of species, like the black petaltail, was harder to determine. That all changed in 1996 when the Dragonfly Society of the Americas assigned common names to the existing scientific names of dragonflies, making identification more friendly to the layperson.
Life history of the black petaltail
Most dragonfly larvae—nymphs—live underwater. Black petaltail nymphs, however, live in mud. It is their habitat requirements that make them unique. Because their habitats are small and sparse, these creatures are relatively rare.
“It inhabits bogs, places where there’s a spring,” says biologist Dr. Chris Beatty of Santa Clara University. “Places where the soil is really saturated.”
Beatty is currently finishing up a two-year study of black petaltails, one that is funded by a grant from the National Geographic Society.
“They dig a burrow underground, and it fills with water,” Beatty explains. “Then they wait at the surface and if they sense something going by, they’ll jump out and grab it.” According to Beatty, their favorite foods include trapdoor spiders and antlions.
Spring-fed bogs are the minority among wetlands. Running water may enhance the habitat for these nymphs, and could explain why many black petaltails are often found in mountainside bogs, where groundwater emerges and flows down the slope.
“For this species, you really have to focus in on finding these bogs. They’re sort of unique habitats,” says Beatty. “There are a lot of characteristic plant species (in these bogs), a lot of them are carnivorous plants, things like sundews, like the giant pitcher plant, Darlingtonia.“
Darlingtonia californica, commonly known as California pitcher plant, is also rare. Its highest concentration occurs in seeps and streamsides in the serpentine soils in Klamath-Siskiyou mountains of southwest Oregon. An easily accessible spot to view Darlingtonia—and also black petaltails—is on the BLM interpretive trail on Eight Dollar Mountain near Selma, Oregon.
Other hotspots for the black petaltail in the state of Jefferson, according to Beatty, are the Scott River Valley, small tributary creeks of the Klamath River, high elevation bogs in the Trinity Alps, in scattered bogs in the Umpqua and Rogue watersheds, and especially in Josephine County.
As if being a mud-dwelling dragonfly wasn’t unusual enough, the black petaltail belongs to a family of the longest surviving dragonflies in the world, the Petaluridae. Most dragonfly species hatch, grow as a nymph, metamorphose into an adult, mate and die all in a single year of frenzied living.
Black petaltails, by contrast, spend five years in the mud as a nymph, before living out their entire adult life in a short three to six weeks. Scientists have not figured out why this Peter Pan of an insect spends so much of its life in a youthful form, but Chris Beatty hopes to get closer to unraveling this mystery.
“How fixed is that development time, is it always five years, or are there years with a string of longer summers so the larvae grow at a more rapid rate,” asks Beatty. “Could some turn into adults after four years, and some take six?”
If the development time of five years is fixed, there would be no way for nymphs born in different years to mate as adults. In this scenario, the black petaltail reproduction cycle would resemble that of salmon, where individuals returning to their natal stream are usually born in the same year.
Beatty is using genetics to help answer this question. He is comparing the DNA of nymphs born in the same year—an annual cohort—within the same bog and across multiple bogs. A study of mutations in the insects’ genes may show if nymphs born in a single year do in fact interbreed with nymphs born in a different year.
“We do have some initial data,” says Beatty. “It’s preliminary, but it suggests that the bogs are really quite different.” If this is true, Beatty believes, the nymph development time really is fixed, and the cohorts don’t interbreed.
Salmon travel long distance from, and back to, their natal streams. But do dragonflies do the same? Beatty is also trying to determine the range of the black petaltail.
“We’re also interested in dispersal: as adults, are they pretty much staying in the same area the emerged from?“ asks Beatty. To that end, he has attempted to attach tiny radio transmitters to the black petaltails, but found that it slowed them down enough where they became more vulnerable to being eaten by predators. The few transmitters that did work showed, says Beatty, “that we didn’t find them moving far away from where we captured them originally and attached the transmitters.”
Beatty is also interested to answer the question of why this species has such a long development time. “We have the 7-year / 11-year cicadas, but you go for all those years and don’t see them, then they all emerge as adults at once,” Beatty muses. “If you go to any place where you see petaltails, you’ll see them every summer.” The answer to this question, however, will have to wait for his next research grant.
Dragonflies in myth and legend
Although dragonflies take on positive connotations in Japanese and Native American cultures, in traditional European cultures, they have taken on a malevolent aura, one based on misunderstanding of dragonfly anatomy. These scary folk tales persist today all across the United States, as Kathy Biggs discovered when she enlisted the help of her twelve year old niece in building a pond.
“When this big red orange dragonfly came into the pond she was frightened and tried to run away,” Biggs recalls. “She said, ‘it’s a dragonfly it might bite me, it might sting me. ‘“ With its huge eyes and narrow, slender body, this pre-Jurassic remnant may appear scary, but it has no stinger or teeth. It doesn’t help, of course, that Hollywood has often used giant intimidating-looking dragonflies as consorts of the Tyrannosaurus Rex.
“She and I got within two feet of it and we were watching its abdomen contract and expand as it was breathing, and we looked into its liquid red eyes,” says Biggs. “She got over her fear of dragonflies and I fell in love with them.” Biggs points to this experience as the genesis of what has become her passion over the past fifteen years.
The association of dragonflies and biting is memorialized in our scientific language. They belong to the order Odonata, which is from the Greek word for tooth. Use of their serrated teeth, however, is reserved for their prey, not humans.
The “stinger” or “Devil’s darning needle” as it was known in England, is actually a clasping organ that a male dragonfly uses to hold the female during mating. In one folk tale, children were warned that a dragonfly would sew the lips together of a child that lied.
The Welsh name for dragonfly, gwas-y-neidr, literally means “adder’s servant.” The mistaken belief about the dragonfly’s mating appendage may explain why the dragonflies are believed to be able to sew up an injured snake, hence the term “snake doctor” used to refer to a dragonfly in parts of the Southern United States.
If Europeans exhibited a cultural fear of dragonflies, the Japanese were just the opposite.
A famous Japanese haiku, written by the celebrated 18th century poetess, Chiyojo, is typical of that culture’s love with dragonflies. In it, she evokes her young son as he chases a dragonfly on a summer day.
My little dragonfly hunter
I wonder where he is
Off to today.
Even earlier, the 17th century Zen poet Basho chose the dragonfly for one of his verses:
Bright red pepper-pod . . .
It needs but shiny
Wings and look . . .
Dragonflies have made their mark on the Japanese language in other ways, as well. The Japanese word for dragonfly—tonbo—is given as a name to boys to signify courage. The interest and reverence for dragonflies in Japan is so great that the language contains traditional common names for all 200 species found there. One of the ancient words for Japan is ‘Akitsu shima’, meaning “Dragonfly (or Odonate) Island.”
The love of dragonflies persists in modern Japan. The world’s first dragonfly museum and nature preserve is located at Nakamura. Another dragonfly conservation area is located at Okegaya-numa.
Native tribes of the American Southwest often used dragonflies in their legends. In one Zuni legend, the dragonfly was a messenger to the gods on behalf of a pair of lost children. For this reason, it is said, it is taboo to kill a dragonfly. In the Navajo culture, the dragonfly is said to hover over pure water. Perhaps the dragonfly, because it lives around water, was a fortuitous find for the ancients in such a dry region. The Navajo word for dragonflies and damselflies—táni•l’ái—means “which is spread out on water.”
The Dakota/Lakota tribes associated dragonflies with mirage and illusion because their wings beat so quickly the human eye could not follow them. Compared to a bee, dragonfly wings beat slowly. With two large sets of wings, they need only beat their wings 30 times per second to stay aloft, compared with a bee, which beats its wings 300 times per second. Even with slow-beating wings, dragonflies are reputed to be the fastest flying insects, flying at least 35 miles per hour, and up to 60 mph by some reports.
The positive associations of dragonfly in these cultures may be based on interactions with humans, as Chris Beatty has discovered in his research on the black petaltail.
“They are a surprisingly docile species,” says Beatty. “They’re also the dragonfly that’s most likely to land on you… If you’re out hiking past a bog and you have a dragonfly land on you, you’ve probably just found a petaltail, much more so than just about any other species, they’re inclined to do that… if you’re wearing a light colored shirt, a light colored hat, they’ll sight on that as a place to land.
“They don’t have a stinger, they don’t bite. If anything, they’re there to eat the gnats or mosquitoes that might have started swarming around you. I’ve had this happen where I’m walking around and a couple of dragonflies following you around eating the things that are trying to bite you.“
One of the more unusual features of dragonfly anatomy has so far escaped the folklore tradition is that dragonflies do not through breathe their mouth or nose. Kathy Biggs discovered this after observing one unfortunate creature who lived headless for three days.
“A dragonfly can lose its head and survive until it starves to death,” Biggs says. “It doesn’t have a nose, it breathes through spiracles in the sides of its abdomen and its thorax.”
Who knows, but the headless horseman in the Legend of Sleepy Hollow may actually have been a dragonfly.
It is precisely because so little is known about dragonfly habitats and their range that they have not reached center stage in the public land management arena. Only one dragonfly—the Hine’s emerald dragonfly—is listed under the Endangered Species Act (ESA), and the critical habitat of that species is limited to sixteen counties in four Midwestern states.
Unlike the grey wolf and other ESA-listed animals with larger ranges, the black petaltail’s habitat is small, limited to isolated wetlands, some less than an acre in size. Protecting its habitat, then, requires less bureaucracy and is less controversial than for the larger animals at the top of the food chain.
“The biggest thing is, leaving it alone so you don’t change the hydrology, so the bog doesn’t dry up,” says researcher Chris Beatty. “Their habitats are localized, so it’s easy to set them aside. For cattle grazing, it’s easy to fence off the areas. Avoiding them isn’t difficult.“
This is precisely what the BLM found last year in a project to clean up mercury-contaminated mine tailings at the Sonoma Mine.
“Kathy (Biggs) showed us that our road widening was headed toward one of only 200 places where the black petaltail is found,” recalls Gary Sharpe, Associate Field Manager for the BLM in Ukiah, California. “The next week we staked it off, avoided it, and widened our road in the other direction. It was an easy thing for us to do. We’re glad we could do it.”
As research dollars become increasingly scarce, the best hope for learning about the black petaltail and other dragonflies may lie in following the lead of birders. For decades, the Audubon Society—through their celebrated Christmas Count and other events—has enlisted the help of bird enthusiasts to help record the presence and abundance of bird species around the globe. The Portland-based Xerces Society is an international conservation non-profit that focuses on invertebrate species. Xerces is poised to embark on a project to employ this brand of citizen science to learn the secrets of dragonfly migration.
“We’re part of the new Migratory Dragonfly Partnership, that includes academics, non-profits and federal agencies, with support from the U.S. Forest Service,” says Celeste Mazzacano, staff scientist for the Xerces Society. “We’re now where we were two decades ago with the monarch butterflies.”
The discovery of the monarch’s overwintering home high in the mountains of Michoacan in Mexico was made with the help of an extensive network of volunteers. The dynamics of dragonfly migration appear to be more complex than those of the monarchs.
“They migrate in swarms, some fly high up. You can see thousands of them for an hour then you lose them,” Mazzacano explains. “Every species that migrates has both resident and migrating individuals in the same habitat.“
Like birds, dragonflies seem to move in flyways. “Some are on the East coast, some in the Midwest, and we’ve seen some—like the variegated meadowhawk—on the Oregon coast,” says Mazzacano. “The southward flight in Oregon is in late September and early October. We’ve observed the green darner returning Northward in April and May,” Mazzacano adds.
Xerces is developing an identification guide for common dragonfly species to help citizen scientists. These volunteers will most likely record the duration, timing, abundance and species. Weather on both the day of the observation and the day before will also be important data.
“We’re looking for environmental cues to help learn about migration and to figure out where we need observers,” says Mazzacano.
Dragonfly migration has sparked the interest of the U.S. Forest Service for other reasons, including their association with sensitive bird species.
“The (dragonfly) migration is tied to raptor migration,” says Carol Lively, coordinator of the Wings Across the Americas program for the Forest Service. “Raptors use them as food.” Each year, the Forest Service confers awards for international conservation efforts on groups working with migratory birds, butterflies and bats. This year they added dragonflies to the awards list.
Dragonflies may one day play a role in the Forest Service’s aquatic conservation strategy as well. “People have turned their binoculars to dragonflies,” says Lively. “They’re associated with good quality wetlands.”
The black petaltail leads the way in the wetlands department, with its habitat requirement of wetlands with cold, flowing water.
“If Jefferson ever decides to declare a state insect,” says Dr. Chris Beatty. “I think the black petaltail would be an excellent candidate.”