WHAT’S IN YOUR ATTIC? BROWN MARMORATED STINK BUGS, PERHAPS

By Arthur V. Evans

Last month, while attending a meeting of the Bull Run Mountains Conservancy held in The Plains, Virginia, I was approached by several members who wanted to know about a stink bug that had invaded their homes by the dozens or hundreds in the fall. At first I thought they were referring to a species of bark stink bug, Brochymena, which sometimes enters homes by hiding under the bark of firewood hauled inside for the fireplace. Just as I was going into my spiel about sending me a photograph or a specimen for identification, someone said, “Look! There’s one!”

 

The brown marmorated stink bug, Halymorpha halys Stål, is steadily expanding its range across North America.

 

Sure enough, a robust gray stink bug was slowly making its way up the wall toward a window through which the day’s last rays of sunlight were shining. Judging from its distinctive markings, I knew that it was not a species of Brochymena and wondered if it might be the brown marmorated stink bug (BMSB), Halymorpha halys Stål. My suspicions were soon confirmed.

This uninvited insect from Asia has proven to be quite a nuisance to many homeowners in northeastern United States for the past several winters. They are much more likely to take up residence inside buildings than either of their native look-alikes, Brochymena and Euschistus.

BMSB was first reported from Allentown, Pennsylvania in 2001, but it turns out that the species has been in that area since at least 1996. The very first individuals probably arrived in America as stowaways, possibly as eggs, on packing crates most likely shipped from China or Japan. Since then, they have spread throughout Connecticut, Maryland, New Jersey, New York, Pennsylvania, Virginia, and West Virginia. As of 2004, an isolated population has become established in Oregon.

Like other stink bugs in the family Pentatomidae, BMSB are “shield-shaped” in outline. They are about 17 mm in length and are nearly as wide as they are long. Unlike similar species of native stink bugs, BMSB has white bands on the antennae and dark bands along the edges of the abdomen surrounding the wings. The head and pronotum (upper surface of the mid section, or first thoracic segment) have patches of small, round coppery or metallic bluish pits. The glands that put the stink in these and other pentatomids are located on the underside of the thorax and upper surface of the abdomen.

 

A nymph of the brown marmorated stink bug, Halyomorpha halys.

 

Brown marmorated stink bugs probably produce a single generation per year in America, but records from the sub-tropical regions of China indicate that there are 4-6 generations annually. Local populations of adults emerge from their winter hideaways in early June and begin mating and laying eggs almost immediately. The small black and red larvae (nymphs) soon hatch and molt five times during the months of July and August. Adults appear in mid August and begin seeking overwintering sites by mid September as the evenings start to become cooler.

To escape the cold, BMSB enter homes, out buildings, office buildings, and other structures by crawling under siding and shingles, around door and window frames, and into crawl spaces and attics. Once inside, they will settle in and become inactive for short periods. However, reinvigorated by the warmth of home heating systems, they are driven to crawl over walls and furniture, or fly clumsily to lights and windows.

As they bumble about, BMSB leave their odor on everything they land and crawl on. The accumulation of this odor at a good hibernation site serves as a powerful chemical beacon that attracts their brethren to the same location year after year.

The best way to keep BMSB out of homes and other structures requires preventative measures to be taken during the summer, after the bugs have already left, to prevent a re-infestation in the fall. Seal cracks and spaces around doors, windows, vents, utility access points, siding, trim, fascia boards, and chimneys. Caulk is handy for small cracks, but wire mesh and screens may be required when dealing with larger spaces associated with attics and foundation vents.

The good news is that once inside your home, BMSB will not bite you or your pets, spread disease, nor lay their eggs. Their piercing-sucking mouthparts are adapted for drawing sap from plants, not damaging furniture, clothing, or other household items.

Using insecticides on BMSB indoors is not particularly effective. Crushing them or sucking them up with a vacuum cleaner causes them to release their noxious odors that may persist in a room or on cleaning implements for sometime. Any disturbance perceived by the bugs as a threat will cause them to stink as a defensive measure. The best thing to do is to simply let them walk on a piece of paper and take them directly outside.

What is being done about BMSB nuisance in America? Since they have yet to become serious agricultural pests here in the States, there is little incentive for chemical companies to develop pesticides to combat them. Pesticides of any kind are incredibly expensive to bring to market and the number of homeowners plagued by home invasions of these bugs will never support the company’s efforts to recoup their investment, much less generate a profit.

But all is not lost. Researchers are learning everything they can about BMSB so that they can identify the weak links in their life cycle and exploit them to affect some level of control. Select BMSB genes and proteins are being sought for the possible development of genetically modified crops that will help suppress their numbers. There is also the possibility of using parasitic insects that will attack stink bugs during egg stage, not only to lessen their potentially harmful impact on crops such as soybeans, cotton, and corn, but also to reduce the numbers of individuals seeking shelter for the winter.

One of the more promising avenues of research involves the synthesis of attractant chemicals, or pheromones, to use in stink bug traps. Although BMSB attractant pheromone is currently unknown, scientists have discovered that they are attracted to the pheromones produced by the male of another species of stink bug native to Japan, Plautia stali Scott. Traps in America baited with this pheromone not only attract BMSB, but also some native species of stink bugs and a tachinid fly, Trichopodes pennipes,  that parasitizes native stink bugs.

Why would these stink bugs and one of their natural enemies be attracted to the pheromone of another species of stink bug? Research on other stink bugs species suggests that some use the pheromones of stink bug species other than their own in an effort to locate better feeding sites. Further, this chemically induced aggregation of different species of stink bugs may serve as a defensive strategy known as the “selfish-herd effect.” As the herd, or aggregation, grows individual stink bugs are increasingly less likely to be selected by a parasitic fly that, not so coincidentally, uses the very same pheromone to locate its victims. The discovery of the attractiveness of this pheromone offers up a potentially useful tool for monitoring and managing BMSB in America.

BMSB is steadily expanding its range across North America. Although clearly annoying to homeowners, the degree to which this species will become an agricultural pest in America remains unclear, especially as it moves south into warmer climates. Within their native range of China, Japan, Korea and Taiwan BMSB is most certainly an agricultural pest, attacking soybeans, apples, peaches, figs, mulberries, citrus, persimmons, and a variety of ornamental plants.

For now, all we can do is batten down the hatches and hope that science will come to the rescue.

© 2010, A.V. Evans

WINTER DARK FIREFLIES

By Arthur V. Evans

Today was cool, gray, and blustery–not exactly what I would call ideal conditions for finding insects. Nevertheless, I set out for the woods along Jordans Branch in Bryan Park here in Richmond, Virginia in hopes of finding early spring species to photograph. I ambled down a trail through a stand of holly toward a mixed woodland of loblolly pine and various hardwoods. As I knelt down to inspect the trunk of a pine snag, a faintly beetlish outline partially hidden in a crack in the bark caught my eye.

The winter dark firefly, Ellychnia corrusca, is mostly dull black with yellow, orange, or reddish arched bands along the sides of their midesection.

It was a winter dark firefly, Ellychnia corrusca. Flat and soft-bodied, the beetle measured slightly more than one half inch in length. It remained motionless until I gently coaxed it out of its hiding spot with a pine needle for a better look.

Winter dark fireflies are mostly dull black, but the sides of their flattened, shield-like midsections are marked with yellow, orange, or reddish arched bands. Their soft, pliable wing covers are clothed in short, fine, golden hairs.

Mature larvae pupate in dead logs, especially pines. Adults emerge in late summer and fall and are sometimes encountered on trees or on the flowers of goldenrod and other asters. As temperatures begin to drop, they seek protected places under bark for the winter. The beetles reappear on late winter and early spring days, either resting on bark or circled around sap flows on maples like cattle around a trough.

Like their more familiar cousins of summer, winter black fireflies are bioluminescent, at least for a while. Both the larval and pupal stages produce their own light. Even freshly emerge adults maintain this youthful glow, but as the beetles grow older they lose their light-producing organs.

Mating winter dark fireflies are not an uncommon sight. Their courtship involves two stages. First, the male climbs on the back of the female while constantly touching her with his antennae and mouthparts. This activity alone may last for up to half an hour. Afterward, the couple consummates their relationship by joining their bodies as they face away from one other. Sometime during the next hour or so, the male transfers a protein-packed packet, or spermatophore, to the female. Pairs of beetles sometimes remain joined together this way for up to an entire day. Over the next several days the female will slowly digest the spermatophore inside her body and store it as a source of energy in her body. Both males and females will mate several times before dying in late spring or early summer.

When attacked, these beetles exude a bitter fluid from their leg joints. This defensive strategy, known as reflex bleeding, is also practiced by other species of lightningbugs.In spite of their chemical defenses, phorid flies attack winter dark fireflies and their kin. Just how the flies locate their hosts is unknown, but their maggots develop inside the beetle, killing their beetle host as they emerge to pupate.

Recent studies suggest that winter dark fireflies are not a single species, but represent a complex of closely related, yet undescribed species that inhabit most of eastern North America. The taxonomy and natural history of these handsome, delicate, harbingers of spring would make an excellent study for a student looking to make a significant scientific contribution to the study of North American beetles.

© 2010, A.V. Evans

THE FOREST CATERPILLAR HUNTER, Calosoma sycophanta, IN VIRGINIA

By Arthur V. Evans

In July of 2008, while conducting a beetle survey of the Bull Run Mountains Natural Area Preserve in Fauquier and Prince William counties in Virginia, I found numerous metallic green elytra scattered along a foot trail winding through an oak woodland on a west-facing slope. The area had been heavily infested with larvae of the gypsy moth, Lymantria dispar, as evidenced by thousands of larval exuviae and pupal cases that festooned the trunks of oaks and other hardwood trees.

At first glance, I thought the beetle remains were those of the indigenous caterpillar hunter or fiery searcher, Calosoma scrutator, a common, brightly colored, and widespread carabid beetle found in the mountains and lowlands of Virginia. Closer inspection revealed that the elytra were much brighter and more yellow than those of C. scrutator and lacked the characteristic coppery red margins.

Further searching in the area produced a very fragile, yet nearly intact specimen ensnared in an abandoned spider web. The pronotum of this specimen was mostly black with metallic blue along the margins, rather than bluish with violet or coppery yellow green borders typical of C. scrutator. Of the five other species of Calosoma known in Virginia, only C. wilcoxi has entirely metallic green elytra, but it is smaller and much duller than either C. scrutator or the silk-wrapped remains in question. (Figure 1).

Figure 1. The Virginia species of Calosoma (from top to bottom, left to right): C. calidum (F.), C. externum (Say), C. frigidum Kirby, C. sayi Dejean, C. scrutator F., C. sycophanta (L.), and C. wilcoxi LeConte. The scale bar equals 5.0 mm. © 2009, Chris Wirth.

I soon realized that what I had in my possession were the remains of a European species, the forest caterpillar hunter, C. sycophanta. Long known as an important predator of gypsy moth larvae in France, 4,046 of these beetles were imported into the United States between 1905 and 1910, most of which were released in New England to combat outbreaks of two European species of lymantriids: the gypsy moth and the browntail moth, Euproctis chrysorroea.

In the United States, the forest caterpillar hunter is established in Connecticut, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Rhode Island, Vermont, and Washington. They have been released in Delaware, Michigan, Washington, and West Virginia, but they have yet to become established in these states. In spite of releases on Vancouver Island, British Columbia, Quebec, New Brunswick, and Nova Scotia, the forest caterpillar hunter does not appear to be a permanent resident in Canada either.

Both the adults and larvae climb trees to attack and eat caterpillars and pupae of gypsy moths and other species. Adult males are more likely to be found on tree trunks, while females tend to remain on the ground. Based on observations in the laboratory and in the field, both sexes are active day and night. Males tend to be more conspicuous as they spend most of their time actively searching for mates. The more secretive females spend much of their time buried in the soil and hidden among leaf litter to feed and lay eggs.

Adult activity coincides with the larval activity of the gypsy moth. Beetles emerge from their overwintering sites in June to search for prey and mates, although some beetles may remain dormant for up to two years. Although adults are strong and agile fliers capable of leaving their overwintering sites behind to search for high populations of caterpillars, their appearance at new outbreaks of gypsy moths is by no means certain. In fact, beetles released as part of biological control programs often remain near their release site.

Forest caterpillar hunters will attack a variety of other caterpillar species, but are most abundant where populations of gypsy moth caterpillars are high. They remain active for about a month, re-enter the soil, and remain there until the following spring.

Adult predation is not this species’ primary impact on gypsy moth populations. It’s greatest impact is through larval production and the voracious appetites of the beetle’s larvae for mature caterpillars and pupae. The ability of adult beetles to reproduce is directly dependent upon the availability of high densities of gypsy moth caterpillars, especially since females require sufficient protein to ensure successful development of their eggs.

Eggs are laid in the soil beginning in early July and hatch in 4-7 days. The larvae climb trees in search of caterpillars and pupae. The remains of pupae attacked by beetle larvae have characteristically large and jagged holes. Mature beetle larvae seek pupation sites in the soil. The entire life cycle, from egg to adult, takes about seven weeks. In Connecticut, adults are known to live three to four years.

Anecdotal evidence suggests that forest caterpillar hunters are potentially important predators of gypsy moth larvae and pupae, but there is still much to learn. Nearly all of the information on the ecology and behavior of C. sycophanta was gathered during the brief period of adult activity that coincides with gypsy moth outbreaks, but little is known about the ecology of this species between outbreaks.

Many thanks to Chris Wirth for the wonderful color plate. This essay is excerpted from Evans, A.V. 2010. The forest caterpillar hunter, Calosoma sycophanta, an Old World species confirmed as part of the Virginia beetle fauna (Coleoptera: Carabidae). Banisteria [2009] 34: 33-37. The full article is available at http://fwie.fw.vt.edu/VNHS/banisteria/banisteria.asp.

©2010, A.V. EVANS

JOHN BANISTER, VIRGINIA’S FIRST NATURALIST

BY ARTHUR V. EVANS

The significance of Virginia as a cradle of natural history study in North America is largely overshadowed by the region’s cultural milieu of indigenous peoples, colonialism, war, and social upheaval.

Nonetheless, the study of natural history in the state goes back more than 300 years. The Reverend John Banister (1650-1692) was Virginia’s first trained naturalist. Although primarily interested in plants, he was an avid student of all natural history, especially insects and spiders.

Banister trained to be an Anglican minister at Magdalen College, Oxford University. During his tenure as a student, Banister displayed a strong interest in natural history that caught the eye of one of his professors, Robert Morrison. Working on his own volume on plants, Morrison convinced the Bishop of Oxford, also a botanist, to send young Banister as a minister to the James River area in the Virginia Colony, presumably to care for souls and certainly to collect plant specimens and seeds.

Banister set sail for the New World in 1677. He arrived in Jamestown sometime before Christmas the same year on the sailing ship Hopewell and proceeded up river to the Falls, the future site of Richmond. There he met William Byrd I, a prominent landowner and trader.

Byrd was instrumental in securing books, paper, and drawing materials in England to support Banister’s natural history studies. Banister accompanied Byrd’s expeditions into the frontier, including short forays into the mountains, and gathered numerous specimens of plants, insects, and spiders.

In 1680, Banister sent his first shipment of Virginia specimens and drawings to Morrison, which included the first samples and renderings of the insectivorous pitcher plant. His drawings and specimens of insects and spiders wound up in the hands of the renowned English naturalist and physician, Martin Lister.

"Vespa Ichneumon" from "John Banister and his Natural History of Virginia 1678-1692," Joseph and Nesta Ewan (1970, University of Illinois Press).

Banister’s efforts to observe and record Virginia’s natural history were severely hampered by the financial uncertainties of his day. Ministers were largely supported by large and cumbersome donations of tobacco from colonists. Then, as now, government funding for basic scientific investigations was woefully inadequate.

To support himself, his family, and his natural history studies, Banister acquired 1,735 acres of land in Charles City County in 1690. That same year he sat on the newly formed committee that met to establish the College of William and Mary which, due to financial difficulties, did not receive its charter until after Banister’s untimely death in 1692.

While accompanying Byrd on a trip to the Roanoke River, Banister was accidentally shot and killed by another member of the party. His natural history collections and copies of his catalogues were packed up and shipped to London, but his library of natural history books remained in Virginia with Byrd, who hoped in vain that they would be used by Banister’s successor.

Some of Banister’s Virginia insect observations appeared posthumously in the Philosophical Transactions, published by the Royal Society in London in 1701 (available online at JSTOR). His lively accounts of such familiar insects as carpenter bees, hornets, body lice, lightning bugs, cicadas, dung beetles, and others make great reading.

Banister’s legacy lives on today in the Virginia Natural History Society. Founded in 1992, the Society publishes Banisteria, a journal devoted to the natural history of Virginia. Each issue is chock-full of articles covering botany, zoology, ecology, and geology, all vital to our understanding of Virginia’s incredibly diverse natural heritage.

To read more about the fascinating life and contributions of Virginia’s first naturalist see: John Banister and his natural history of Virginia 1678-1692, by Joseph and Nesta Ewan (1970).

© 2010, A.V. Evans

WOOD-EATING COCKROACHES INVADE VIRGINIA

By Arthur V. Evans

Just kidding. Wood-eating cockroaches have really been here in the Commonwealth all along. But they only eat really rotten wood, so they pose no threat to buildings or furniture. Let’s start at the beginning.

A few years ago, while conducting an insect survey in Shenandoah National Park, I pulled apart a very moist, rotten log to find several shiny black cockroaches over an inch long living in flattened tunnels apparently chewed out of the wood. With chunky, wingless bodies, and thick spiny legs, they resembled somewhat stunted versions of Madagascan hissing cockroaches, popular denizens of insect zoos and the occasional of pet shop.

I recognized these cockroaches immediately as the famous brown-hooded wood cockroach, a native species that has figured prominently in the scientific literature, especially over the last 10 years. Samuel Hubbard Scudder described Cryptocercus punctulatus in 1862 from a single specimen collected right here in Virginia. Draper Valley in Pulaski County, to be exact.

The brown-hooded wood cockroach, Cryptocercus punctulatus Scudder

Scudder was a noted authority not only of grasshoppers, cockroaches, and their relatives, but also of butterflies and fossil insects. He coined the term “Cryptocercus” from the Greek “krypto,” meaning to hide or conceal, and “kerkos,” or tail. This is in reference to the fact that the last three abdominal segments of Cryptocercus are hidden within a chamber created by the seventh abdominal segment.

Cryptocercus cockroaches are no ordinary cockroaches. They takes four to five years to reach maturity, mate for life, reproduce only once in their lifetime and only after they have lived as a couple for a year. Both sexes actively care for their young for up to three years. Most other cockroaches live only two or three years, are quite promiscuous, breed repeatedly, and never see their young, abandoning their eggs before they hatch.

Like termites, adult Cryptocercus chew meandering galleries in rotten logs of both coniferous and hardwood trees. The galleries consist of intersecting tunnels and arena-like chambers in which they raise their young. Females imbed egg cases, or oothecae, in the walls of the tunnels. The larvae, up to as many as 75 in a single brood, change from ivory or golden in color to progressively darker shades of reddish brown as they mature before eventually turning nearly black.

Both parents and offspring eat rotten wood and rely on bacterial and protozoan symbionts in their gut to help them metabolize their food; only termites and Cryptocerus cockroaches harbor these same specific gut symbionts. Since they come into this world without the necessary compliment of gut symbionts, Cryptocercus larvae must obtain them from special anal fluids produced by their parents, just like termites. Up to six cockroach larvae at a time will bury their heads deep within the anal chamber of an adult cockroach to suck up an elixir rich in life-giving bacteria and protozoa.

Young cockroaches grow by molting, or shedding their exoskeletons. As they molt, part of their intestinal lining is also shed, and along with it goes their gut symbionts. After each successful molt they must re-infect themselves by imbibing the anal fluids of their parents in order to metabolize wood and stay alive. By the time they reach their third or fourth larval stage, the young Cryptocercus no longer lose their gut symbionts with each molt and have become nutritionally independent of their parents. Also like termites.

Scientists have long thought that termites were offshoots of ancient cockroaches. Whether Cryptocercus cockroaches are “living fossils”  closely related to termites, or a more recently evolved line of cockroach that just happens to share an amazing number of features in common with termites is still hotly debated in the scientific literature.

Scientists eager to explore the interface of population genetics and environment, the key evolutionary forces that drive the development of new adaptations and speciation, find these cockroaches elegant research subjects. After all, they are dependent on a patchy resource (rotten logs), have limited powers of dispersal, and live in close-knit family units. Plus, whether they are primitive or not, the reproductive behavior of Cryptocercus mirrors that of a king and queen termite starting a new colony, which makes them the best living models for studying the development of social behavior in modern termites.

In the 1930’s two additional species of Cryptocercus were discovered in eastern Russia and western China. In 1997, comparative DNA analysis of populations in Appalachia and the Pacific Northwest produced results indicating that each population was actually a distinct species. A similar analysis of the Appalachian populations revealed a complex of four closely related species. One of the new species was named, predictably enough, after Charles Darwin (C. darwini), while another was named in honor of Jerry Garcia (C. garciai) of the Grateful Dead.

Since 1999, an additional five species have been found in East Asia, bringing the total number of species in the world to an even dozen. More species no doubt await discovery by scientists. From Draper Valley, Virginia to China, our understanding of Cryoptocercus and the light they might shed on the very dawn of termites continues to be a long, strange, yet very illuminating trip.

© 2010, A.V. Evans

DARWIN WAS A BEETLE MAN

Just a few days ago I was rummaging through my backlog of reprints and journals when I discovered a filing folder labeled simply “Darwin.” How propitious that this meager collection of notes and papers on Charles Robert Darwin’s   entomological influences and contributions should surface just days before his 200^th birthday on February 12!

Back in 1994, I had embarked on what could be called a Darwin quest. I read as much as I could about him and, more importantly, by him.  I started with a book entitled Darwin for Beginners for a light, yet interesting overview of his life before sinking my teeth into meatier works, such as Darwin, which provides a detailed and engaging account of this great man’s amazing life. I then read “The Autobiography of Charles Darwin and Selected Letters” edited by his son, Francis Darwin, originally published in 1892, just 10 years after his father’s death (see another edition). Then it was on to “The Voyage of the Beagle,” published by Darwin himself and one of the great natural history classics of all time. And finally, I attempted to absorb what is perhaps his best known work, On the Origin of Species, By Means of Natural Selection or the Preservation of Favoured Races in the Struggle of Life, which has been reprinted many times over. Hardly an exhaustive reading list, I know, but it was what I could muster in the six months before my trip to England in October.

One of the many aspects of Darwin’s life that continues to resonate with me is the fact that insects had such an influence on him throughout his life and work. Although none of his writings are exclusively entomological, Darwin still incorporated various aspects of insect behavior in widely disparate works as he constructed his syntheses to describe the underlying principals of natural selection.

As indicated in his early letters and autobiography, Darwin’s young life was often consumed by collecting insects, especially beetles.  He was later introduced to entomology through his cousin, W. Darwin Fox. It was Fox that introduced young Charles to other naturalists while attending university, including Professor John Stevens Henslow at Cambridge, the man who would eventually recommend Darwin for the job of the sole naturalist on the H.M.S. Beagle on its voyage around the world from 1831 to 1836.

While studying at Cambridge, Darwin would slip into the countryside at every opportunity to search for rare species. Recounting one such adventure in his autobiography, Darwin wrote “I will give proof of my zeal: one day, on tearing off some old bark, I saw two rare beetles, and seized one in each hand; then I saw a third and new kind, which I could not bear to lose, so that I popped the one which I held in my right hand into my mouth. Alas! It ejected some intensely acrid fluid, which burnt my tongue so that I was forced to spit the beetle out, which was lost, as was the third one.”

I have two favorite Darwin “beetle quotes.” The first appeared in a letter he wrote to botanist J.D. Hooker in 1858 that appears in his autobiography: “I feel like an old war-horse at the sound of a trumpet when I read about the capture of rare beetles—is this not the magnanimous simile for a decayed entomologist? It really almost makes me long to begin collecting again.” The second quote is taken from The Descent of Man: “From the small size of insects, we are apt to undervalue their appearance. If we could imagine a male Chalcosoma with its polished, bronzed coat of mail, and vast complex horns, magnified to the size of a horse or even of a dog, it would be one of the most imposing animals in the world.” When it comes to what we humans consider important, size apparently does matter!

My actual pilgrimage began not long after I arrived in London when I walked into Westminster Abbey to visit his final resting place among the remains of other great scientists, writers, politicians, royalty, and other important figures in English history. I found Darwin’s name, and date of birth and death all carved in stone. His body was interred in the north aisle of the Nave, just a few feet from the grave of Sir Isaac Newton. Later in the week I stopped by the Royal Entomological Society, where Darwin had long been a member in good standing. To this day I can still see and smell all those classic insect books in the library and continue to marvel at all of those incredible tomes together under one roof!

But the pinnacle of my Darwin pilgrimage was Down House in Kent, Darwin’s home set in the North Downs countryside just 16 miles from downtown London. He lived here as a country gentlemen from September of 1842 until his death on April 19, 1882. It was also here that he immersed himself in research, corresponded with the imminent scientists of the day, and penned his greatest works.

One of the things that has always fascinated me about great scientists with a penchant for popular writing is not only how and when they write, but also where they work. The condition and layout of Darwin’s study was just as it was when he was alive and delving into the mysteries of the natural world and claiming his place in history. There was even a display of a portion of Darwin’s beetle collection, nearly all British in origin and unlabeled. Then there was his beloved “Sand-walk,” a graveled path where the great man would ambulate each day around noon to think. Seeing the very same landscape in which Darwin retreated to ponder, synthesize, and create “On the Origin of Species”  and his other important books was truly a humbling experience. A visit to Down House and its surroundings is indeed a visit to hallowed ground.

An important and engaging summary of his entomological work by Jeanne and Charles Remington entitled “Darwin’s Contributions to Entomology” appeared in the Annual Review of Entomology in 1961. Another enlightening and very useful overview is Darwin’s Insects, edited by Kenneth G.V. Smith and published in the Bulletin of the British Museum in 1987. Within this fascicle is a collection of notes and comments by Darwin on the insects he collected in Britain and on his voyage on the H.M.S. Beagle.

There are lots of Darwin sites on the web. To see and read Darwin’s works and letters, or descriptions of his specimens, visit The Complete Works of Charles Darwin. See also Darwin 200, the Darwin Collection at English Heritage, and AboutDarwin.com.

©2009, A.V. Evans

OUT WITH THE NIGHT SHIFT

It’s late afternoon. The air is hot and thick, draped like a hazy, wet blanket over the landscape. The dull orange sun hangs heavy over the tops of trees lining the lake and soon drops out of sight. Whirligig beetles drift lazily in the placid water, barely leaving a ripple in their wake. Dragonflies dart back and forth, gobbling up their final meals of midges and other tiny flying insects for the day.

As dusk approaches the throbbing wail of cicadas loses its urgency and eventually stops, as do the relentless attacks of blood-sucking deer flies. The white-throated swifts that had ruled the skies for most of the afternoon are now settled in for the night, giving way to their mammalian counterparts, the bats. Several of these amazing animals skim the lake’s surface right in front of me to drink.

I am in the vicinity of Group Camp 7 in the southernmost reaches of Pocahontas State Park. Accessible only on foot or by horseback, this sylvan oasis within the park definitely has a feel of remoteness seldom experienced so close to a major metropolitan area.

With more than 7,600 acres, Pocahontas is the largest state park in Virginia. Located just 20 miles southwest of downtown Richmond, the park is probably best known for its swimming pool, camping and conference facilities, outdoor performances, and music festivals. But it is also a favorite haunt among local naturalists, especially birders. I have visited the park regularly for the past five years to observe and photograph Virginia insect life during the spring and summer.

As the day shift winds down, the creatures of the night slowly begin to stir, gearing up to take their place on the evening stage. With the arrival of twilight there seems to be a moment or two when all insect life seems to pause briefly, and then the night shift takes over.

The twinkling lights of amorous fireflies begin to appear about the low growth sprinkled along the woodland floor. Neither bugs, nor flies, these soft-bodied insects are actually beetles. Males engage in a slow, looping flight with repeated dips to create a J-pattern with their lights. At the bottom of the descent their abdomen glows bright yellowish-green, becoming dimmer before shutting off completely at the top of their ascent. Their oversized compound eyes are trained on the not-so-distant darkness, hoping to see the light of a female responding with her own perfectly timed and pulsating response amidst the low, herbaceous growth.

Later in the evening another species appears, flying high and fast in the canopy, releasing its light in rapid bursts of three. Fireflies have developed this system of luminous Morse code to locate mates of their own kind among the tangled growth and avoid fruitless encounters with the wrong species.

Chunky June beetles begin to rustle, slowly rising through the air from their daytime hiding places amongst the leaf litter with a buzz. They plow through the night air as if they were trucks in low gear, slowly gaining speed as they begin their nightly search for mates and fresh leaves to eat .

With a headlamp strapped to my sweaty forehead, I venture forth like a bright-eyed Cyclops in search of more of the Commonwealth’s nocturnal insect and spider fauna. The forest floor seems to glitter with tiny stars, which turn out to be the tiny, unblinking eyes of wolf spiders reflecting the beam of my light. They too are searching for insects.

As my headlamp cuts through the ever-growing darkness, moths, beetles, and other airborne insects fly in and out of the sharp beam. Some plummet into my face as they try to reach the light’s source.

For years entomologists have taken advantage of the fact that many insects are attracted to lights at night. Using the ultraviolet component of distant light to orient themselves, many insects are uncontrollably drawn to nearby artificial lights, such as flickering campfires, hissing gas lanterns, brightly lit store fronts, and streetlights. Not the sad, dull yellowish lights that inhabit city streets, but the bright, inviting glow of mercury vapor lights that dot the lesser populated areas of the state.

Lights strong in the ultraviolet spectrum are especially attractive to nocturnal insects. I use several BL black lights specifically for attracting night flying insects. Set in front of and above white sheets for reflectivity and contrast, and powered with 12-volt gel cell battery, the eerie purple glow works like a bug zapper, but without the zap.

Warm, humid, moonless or overcast skies seem to be the best nights to “black light” for insects since there is less ultraviolet light to compete with my set up. The greatest insect activity at lights is right after dark, between 9:30 and 11:00 PM, although some of the larger beetles and moths seldom make an appearance before midnight.

Nocturnal insects can easily maintain a steady flight path in relations to distant sources of light. However, they must fly in ever-tighter spirals in order to maintain their orientation to a nearby light source. Eventually they alight on the sheet or nearby vegetation. If left undisturbed, most would remain within sight of the light until dawn when the rising sun would drive them to seek shelter from the heat and hungry birds.

As night falls, insects swirl about my black light like small comets. My sheet was soon covered in a dizzying array of insects ranging from tiny gnats and beetles just millimeters long, to relatively giant mayflies and June beetles. Dozens of plump, fuzzy moths of all colors settled on the sheet like fighter planes on a flat top. Shiny, smooth and streamlined aquatic beetles emerged from the nearby lake and clambered awkwardly beneath the light, like proverbial fish out of water. Perhaps 200 different species of insects in all made an appearance at the light. The preparation and identification of this relatively small showing would require the full-time efforts of an entomologist for at least a year.

Occasionally a bat hurtled through the cloud of insects, gobbling them up as if they were bellying up to an airborne buffet. Using a series of high-pitched clicks like radar to locate airborne insects, the bats dart and bank sharply through the night air in pursuit of hapless insects.

But not all insects are defenseless against bats. Some moths and mantids have special “ears” capable of picking up signals bats use for their echolocation system. Upon hearing the call of a nearby bat, these insects will take sudden evasive action by pulling in their wings and dropping to the ground or making a spiral power dive to safety.

After 11:00 PM the waves of incoming insects began to slow to a mere trickle. I packed up just after midnight, but the choruses of frogs, katydids, and crickets continued to rise and fall. Although I am sure that they sound like a raucous cacophony to many, I found the chirps, clicks, buzzes, twangs, and bellows to be joyous noise, a perfect sound track for an evening out with the night shift.

©2004, Arthur V. Evans

BIRDS, BUBBLES, BUGS: MY FIRST FIELD TRIP OF 2009

Paul Bedell is a man of many talents. A double bassist for the Richmond Symphony, he is also a gifted naturalist. And he is a first-class birder, an indefatigable odonatololgist with a penchant for finding new state records and, as of late, Virginia’s leading authority on robber flies. Paul invited me to join him to today on a survey of rusty blackbirds for the Cornell Lab of Ornithology on a plot of land along the James River near Bremo Bluff in Fluvanna County. The temperature was supposed to surge up to a relatively balmy 60 °F, so I jumped at the opportunity.

Some beetles in eastern North America come out for only a few weeks or so in early spring. They are sometimes considered rare simply because many entomologists have yet to emerge from their own winter torpor in time to find them. I didn’t think that it had warmed up enough for a sufficient period of time to trigger beetle activity of any kind, but figured this would be a good opportunity to get my kit together for the upcoming field season.

There might be other insects out, too. For example, I might happen upon the first mourning cloaks and question marks of the season. These butterflies tuck themselves under bark and other protected places for the winter and are quickly spurred into action by the sudden appearance of a warm winter day. Maybe today would be one of those days when I would see them rocketing from one sunny patch to the next, or sipping nectar oozing from freeze-cracked maple trunks. Or not.

At 9 AM the sky was clear and the temperature had already passed 40 °F as we headed west on Highway 6 on the north side of the James River. We passed through the little towns with names like Manakin, Crozier, and Goochland. Just past Columbia, we turned left toward Bremo Bluff. Our final destination was a plantation called Glenarvon about an hour drive or so from Richmond. The beautiful home with its three columns and four chimneys was built in 1832 by William Galt Jr.

The origin of the name “Glenarvon” is uncertain. There is speculation that it was inspired by the title of a book by the same name penned in 1816 by Lady Caroline Lamb. This quasi-fictional gothic novel was inspired by the author’s four month-long affair with British poet Lord Byron. Or perhaps it was the name of Galt’s birthplace in Scotland. But I digress.

Upon our arrival, we were greeted by Glenarvon’s owner, Bill Winston. Knowing that I was an entomologist, Bill asked me if I knew what these large dark beetles were that he would find dead every now and again during the summer. I suggested a few possibilities, but nothing clicked with Bill. So, I suggested that he save the next one for me so I could identify it.

With a herd of curious cows looking on, Paul and I suited up with our birding, bugging, and photographic gear. We wandered down a narrow road into a ravine cut by a small creek as it flowed toward the James. The stands of trees mostly contained individuals with trunks no larger in diameter than the girth of my thigh. However, right along the creek’s edge stood several giant beeches. I imagined that the smooth, gray, and elephantine trunks of these trees were the legs of a small herd of long-necked sauropods that had come to drink. Again, I digress.

Finding one of these freshly downed trees of size with slightly loosened bark would be like hitting the mother lode. Many beetles and other wood-dwelling insects would find such a resource perfect for feeding, mating, and laying eggs. But I had no luck in finding such a tree. Instead, I contented myself with peeling back small patches of bark at the bases of several standing pine snags, none of which proved to be particularly productive.

I carried on down the road until it ended in a small field. Skirting the edge of this small opening was yet another small creek. I walked over to what looked like a mini-oxbow lake that was no more than three feet deep, 10 feet across, and about 25 feet long. Looking down from the bank, I could see right through the thin sheet of ice that covered the water down to the bottom of the creek.

In hopes of seeing some aquatic insect activity, I walked down to the water. As I approached the edge, a short series of marble-sized bubbles forced their way up from the depths of the submerged leaf pack. The rising spheres quivered like drops of quick silver as they rose up through the water column. Hitting the ice, these parcels of air were instantly pancaked and skittered along the ice, propelled by the current of the creek. No insects were in sight.

As I walked up the bank, a lone eastern boxelder bug flew past by and I watched it until it drifted out of sight. I thought that this colorful insect, pied with red and black, might prove to be the insect highlight of the day. But I was wrong.

Bill caught up with us later in the afternoon, plastic bag in hand. Inside was long dead female eastern Hercules beetle that he had found in the barn. A real beauty, she was. Bill said he had never seen a living one and wasn’t sure just how he would react if he ever did!

After investigating a few more fields and intervening woods, we decided to call it a day. Paul saw some good birds, but didn’t find his rusty blackbirds. But the relatively slow day failed to dampen our spirits. We both agreed that any day out in the field was a good day and began planning our next outing. Stay tuned.

©2009, A.V. Evans

 

 

MOURNING SCORPIONFLIES

Scorpionflies and their relatives belong to the order Mecoptera, a fascinating group of insects with more than 80 species in North America. They are so-named because males in the genus Panorpa (family Panorpidae) have bulbous reproductive organs mounted on the tips of their abdomens that suggest the stinger of a scorpion. However, unlike their arachnid namesakes, scorpionflies are incapable of inflicting any sting whatsoever and are harmless to humans.

The mourning scorpionfly, Panorpa lugubris, is easily distinguished from all other North American Panorpa by its mostly black wings sprinkled with a few white spots. Its body is also black, but with bright and contrasting patches of reddish orange. This species inhabits both the Atlantic and Gulf coastal plains, from Virginia south through the Carolinas, Georgia, and west across the Florida panhandle to Louisiana.

Adults prefer open habitats with sandy soils and are often found flitting about in sandhills and old fields. They are typically encountered in the fall and early winter, but some individuals are out and about from mid-April through early June.

Ollie Flint, Curator Emeritus of Neuropteroid Orders at the National Museum of Natural History, Smithsonian Instiution, stalks the wiley mourning scorpionfly at the Blackwater Ecological Preserve.

I observed some of my first mourning scorpionflies late one morning in September at Old Dominion University’s Blackwater Ecological Preserve in Isle of Wight County. Within the sand ridges of this preserve are two of Virginia’s rarest plant communities–longleaf pine-turkey oak flatwoods and longleaf pine savannas. What the scorpionflies called home was a patch of ground with open and sandy substrate punctuated by patches of low-growing huckleberries (dwarf and blue) and sheep-laurels. The overstory consists primarily of pond and longleaf pine, with an occasional loblolly thrown in for good measure.

Both males and females were found quietly perched with their heads upward on the vertical stems of the huckleberries, but quickly scattered as I approached. Some flew short distances and attempted to land on other low, vertical surfaces. Upon landing, they ran short distances over open ground with amazing speed before once again taking to the air. Others simply dropped down into the vegetation, listing to one side, and remained motionless among the detritus.

In North Carolina, mourning scorpionflies have been found scavenging parasitized tobacco hornworms in recently harvested tobacco fields. Captive adults happily dine on offerings of dead grasshoppers, but the larvae are somewhat more omnivorous. They too scavenge dead insects, but  will also consume bits of mushrooms, tobacco stalks, and tobacco seed capsules.

For more information on mourning scorpionflies see Evans, A.V. & O.S. Flint, Jr. 2009. The Mourning scorpionfly, Panorpa lugubris, in Virginia (Mecoptera: Panorpidae). Banisteria 33: 58-61.

For a terrific overview of order the Mecoptera  in North American check out this issue of the Kansas School Naturalist written by George Byers Entomology Professor Emeritus at the Snow University of Kansas and a world authority of mecopterans.

©2009, A.V. Evans

WINTER STONEFLIES

In Virginia, one of the very first insects to make an appearance in the New Year is the winter stonefly, Taeniopteryx. These flat, slender, and sprawling insects are grayish brown and measure 9.0 to 11.0 mm in length. They are also known by other appellations, such as willowflies and early black stoneflies.

Most of their lives are spent as larvae that nibble on aquatic vegetation and submerged debris as they crawl along coarsely pebbled and rocky bottoms of large streams and rivers. Beginning in late January or early February, the mature larvae leave their watery past behind for good and haul themselves up on nearby rocks and vegetation. The freshly emerged adults, having just escaped their larval exoskeletons, soon festoon boulders, logs, bridges, and nearby buildings by the dozens, even hundreds. They are most evident on warmer days, but are seldom noticed by passersby, save for naturalists on the lookout for signs of life after a long winter or anglers reading the latest hatch.

For me, the sudden appearance of these hardy insects serves as an annual reminder that winter is almost over and spring is on the way. This is welcome news to entomophiles living in the frosty and leafless eastern United States!

Many thanks to Boris Kondratieff of Colorado State University for helping me with the intricacies of winter stonefly identification.

©2009, A.V. Evans