Archive for the Environment Category

A RARE BEETLE NEW TO VIRGINIA

Posted in Beetles, Environment, VCU Rice Center, Virginia on January 22, 2011 by Dr. Art Evans

By Arthur V. Evans

Xylophilus crassicornis Muona. © 2011, A.V. Evans

My insect survey at the VCU Rice Center continues to reveal species that are rarely collected and/or newly recorded for the Commonwealth of Virginia. While sorting through dozens of trap samples containing thousands of insects, I recently discovered three specimens of a rarely collected false click beetle (Eucnemidae), Xylophilus crassicornis. This collection represents the first records for the genus and species in Virginia.

Xylophilus crassicornis was first described by Finnish entomologist Jyriki Muona in 2000 from a single female specimen collected from Maryland in 1902. The specimen was located in the collection of the Entomology Department at Cornell University in Ithaca, New York. A second specimen from Alambama was identified last year. The VCU Rice Center specimens, the sex of which are yet unknown, measure 2.8-4.0 mm and were collected from Malaise traps in May that were placed just northwest of the administrative building and among the vernal pools off Kimages Road.

Malaise trap. © 2010, A.V. Evans

Although relatively little is known of their habits and distribution, false click beetles probably play an important role in the interactions between trees, fungi, and forest regeneration. Further study of their biology may suggest their use as important indicators of forest diversity.

References

Hoffman, R.L., R.L. Otto, and R. Vigneault. 2009. An annotated list of the false click beetles of Virginia (Coleoptera: Eucnemidae). Banisteria 34: 25-32.

Muona, J. 2000. A revision of the Nearctic Eucnemidae. Acta Zoologica Fennica 212: 1-106.

© 2011, A.V. Evans

SKY ISLANDS, DESERT SEA-Part 1

Posted in Arizona, Environment with tags , , , on April 7, 2010 by Dr. Art Evans

By Arthur V. Evans

“…some of the earth’s most interesting “islands” are nowhere near oceans or lakes. They are strictly land islands but with a climate, vegetation, and animal life as different from their surroundings as if they rose from some remote sea.”

Weldon Heald in Sky Islands

A conservationist and journalist, Weldon Heald coined the term “Sky Islands” nearly 60 years ago to describe the archipelago of mountain ranges spanning the gap between the Rocky Mountains and the Sierra Madre Occidental of central Mexico. Made up of more than 40 isolated mountain ranges, the Sky Islands cover two countries in the states of Arizona, New Mexico, Sonora and Chihuahua. The diversity of flora and fauna inhabiting this region is unmatched in temperate North America. Warmer than the Rocky Mountains and drier than the Sierra Madre Occidentale, these unique and isolated mountain ranges support a wealth of temperate and tropical arthropod species.

The mouth of Cave Creek Canyon, Chiricahua Mountains, Cochise County, Arizona.

The Arizona Sky Islands consist of the Santa Rita, Rincon, Huachuca, Santa Catalina, Whetstone, Bobaquivari, Pinaleño, and Chiricahua Mountains. Climbing thousands of feet into the sky, these lush mountains and their canyons stand in stark contrast to the surrounding lowlands. It is the sheer mass and altitude of these ranges that keeps their peaks and canyons much cooler and wetter than the surrounding desert scrub and grasslands. On average, mountain temperatures drop 4 º Fahrenheit for every 1,000 feet of elevation, while at the same time, annual precipitation increases by four inches. These moisture and temperature gradients create life zones that support populations of arthropods poorly adapted for survival in the relatively harsh, dry environs below. Unable to migrate across this “desert sea,” many of the arthropods inhabiting Arizona’s Sky Islands have been marooned for hundreds of centuries.

© 2010, A.V. Evans

FALCATE ORANGETIPS

Posted in Butterflies, Environment, Insects, Virginia with tags , , , , , , , on April 5, 2010 by Dr. Art Evans

By Arthur V. Evans

After a few false starts spring has finally arrived here in central Virginia, and not a moment too soon. In hopes of seeing some examples of the early spring insect fauna, I recently set out on a warm, sunny day for the James River Park near the 42nd Street entrance.

The orange and slightly hooked wing-tips were the unmistakable field marks of the male falcate orangetip, Anthocharis midea, the only species of orangetip butterfly found in the eastern United States.

The latest floodwaters from spring rains had only just receded, leaving a thin and dusty film of silt and debris high above the river’s usual channel in the park. Just past the flood residue, small plants had raised their tiny blossoms high to lure the season’s first pollen- and nectar-loving insects.

As I wandered upriver toward the Nickle Bridge, a flash of white with a hint of rich orange crossed my path. It slowly yet deliberately flitted about the freshly emerged sprigs of green that populated the edges of the path before finally settling for just a moment or two on a small flower. The orange and slightly hooked wing-tips were the unmistakable field marks of the male falcate orangetip, Anthocharis midea, the only species of orangetip butterfly found in eastern United States.

The females lack the orange patch, but are otherwise similar in appearance to the males. The wings of both sexes are mostly white; the underside of the hind wing bears a finely marbled yellowish-brown pattern. From tip to tip, their wings span no more than one-and-a-half inches across.

Falcate orangetips are among the first butterflies to emerge from their pupae in spring. Widespread in Virginia, they are found in a variety of habitats, including parks, rocky mountain outcrops, open deciduous and mixed pine-oak woodlands, sandhills, and floodplain forests, especially along stream and river courses.

Females lay their greenish-yellow eggs singly on the flowers of various cresses and other members of the mustard family. The eggs soon turn red and hatch into ravenous larvae that devour mostly seed pods, buds, and flowers, and not leaves. Because of the limited number of reproductive structures on each food plant, larger caterpillars will not hesitate to eat their smaller brethren to reduce competition for meager food resources.

Mature caterpillars are green or blue-green and sprinkled with shiny dark plates bearing short bristles. A yellow stripe runs down the length of the back, while a broad white stripe runs from the head and along each side and meet on its backside. The winter is spent, sometimes two, as a narrow chrysalis that is sharply pointed on both ends.

Don’t hesitate to look for these attractive insects in an open woodland or bottomland forest near you. By early June the falcate orangetips will all be gone, and you will have to wait until the following spring for the next generation to once again make their brief and welcome appearance as heralds of spring.

© 2010, A.V. Evans

TRUE CONFESSIONS

Posted in Centipedes, Environment, Musings with tags , , on April 3, 2010 by Dr. Art Evans

By Arthur V. Evans

Every now and again I am asked what is my least favorite insect or spider. I really don’t have an answer for this question. But I can say, without hesitation, that my least favorite arthropod is the centipede.

Don’t get me wrong. I think that centipedes are fascinating animals, but every time I happen upon one of the larger species in the Order Scolopendromorpha, I can feel the hair on the back of my neck stand up and a cold chill run down my spine.

A centipede has never bitten me, so my discomfiture is not based on personal experience. But I do know what the larger species are capable of in terms of delivering a painful, yet non life-threatening bite with their powerful fanglike front feet, or gnathopods. Combined with their speed and lithe bodies, centipedes just set me on edge.

Scolopendra heros from southeastern Arizona dining on a young mouse. Note the thick, black gnathopod next below the head.

Scolopendra heros, the largest centipede species in the United States, measures in at a whopping 6.5 inches (16.5 cm). They range from central and southern Arizona east to southwestern Missouri, Arkansas, and Louisiana. This species is extremely variable in color. During the summer, adults are active around the clock and are easily seen in the headlights of a moving car as they cross the highway at night with their fore bodies bobbing up and down.

I used to collect these big bruisers to put on display in Insect Zoo at the Natural History Museum of Los Angeles County. While on the road, I checked their containers often to make that the lids were securely fastened. My travelling companions were regularly warned that if a lid accidentally came off and a centipede was on the loose, I would immediately abandon the vehicle.

Yesterday, while collecting beetles in the Zuni Pine Barrens of the Blackwater Ecological Preserve, I committed a potentially serious faux pas in the field by peeling back some loose bark of a dead loblolly pine tree that was leaning directly over my head.

Hemiscolopendra marginata occurs in Missouri, Oklahoma, and Texas east to Virginia and Florida; it is absent in most of the Appalachians.

Out of the corner of my eye, I saw a blue-green centipede, Hemiscolopendra marginata, fall from its once-secure perch, its two-inch long body trunk twisting in the air in an effort regain some sort of foothold. Before I could react, it slid across my forearm to the leaf litter below. Or so I thought.

For several seconds my mind raced. What if it didn’t fall on the ground? What if it or another centipede landed on my shoulder? What should I do? What if it got inside my shirt? My now fevered brain began imagining the centipede sinking it’s gnathopods into the soft and sensitive skin of my neck. Or worse.

I stood perfectly still in the bright spring sun filtering through the tall and slender pines, my body tingling all over in anticipation of anything from a crawling sensation to a stabbing pain. The centipede was nowhere to be felt or found. Still, it took me several more minutes to become convinced that my person was centipede-free and begin to feel a sense of relief.

Recounting this event a full day later still gives me the heebie-jeebies!

© 2010, A.V. Evans

ALTERNATIVE SPRING BREAK AT THE VCU RICE CENTER

Posted in Education, Environment, Insects, VCU Rice Center, Virginia with tags , , on March 26, 2010 by Dr. Art Evans

By Arthur V. Evans

© 2010, J. Barton

Last week, I met a group of very dedicated and enthusiastic students from the Virginia Commonwealth University and Virginia Wesleyan College at the VCU Rice Center in Charles City County. They had spent the last several days participating in various activities as part of this year’s Alternative Spring Break. Sponsored by the Chesapeake Bay Foundation, Alternative Spring Break provides students with an opportunity to explore and give to their community by providing a week’s worth of environmental and conservation projects, such as planting trees, tending gardens, tidying  up parks and wildlife refuges, and stream cleanups. At the Rice Center, some of the students would have the opportunity to help me with my insect survey.

© 2010, J. Barton

After an impromptu presentation about my survey and some of the methods used to trap insects, my team of volunteers was ready to get started. They grabbed tools and traps and set out for the first trap site. Working like a well-oiled machine and with minimal direction, they quickly established two sets of Malaise, Lindgren, and pit fall traps in less than two hours.

Malaise trap. © 2010, A.V. Evans

What is a Malaise trap you ask? It’s like a tent with its walls on the inside and is specifically designed to capture flying insects, day or night. Upon hitting the internal nylon panels, most insects will eventually work their way up into a collecting container partly filled with alcohol. Malaise traps are usually used to catch flies, bees, and wasps, but other kinds of insects are captured, too. They are typically placed along roads, trails, streams, or forest edges. Up to 1,000 insects a day may be captured in a good site.

Lindgren funnel trap. © 2010, A.V. Evans

Lindgren funnel traps are designed to attract and capture wood-boring beetles and other insects that alight on tree trunks. They consist of a rain and debris guard with a dozen black plastic funnels suspended directly underneath. Attached to the bottom funnel is a specimen receptacle. Each trap is fitted with chemical lures that simulate the odors given off by dead and dying trees. Insects attempting to land on the trap fall down the funnels and into the receptacle at the bottom. Foresters use Lindgren funnel traps to monitor pest insects in stands of managed timber, especially bark beetles.

Pit fall traps connected by drift fences of metal flashing capture small crawling animals,

Pit fall traps. © 2010, A.V. Evans

especially insects and other arthropods. At the end of each drift fence is a single pit fall trap consisting of two 16-ounce plastic drink cups nested in one another and sunk so that the tops are flush with the soil surface. The inner cup is partly filled with environmentally “friendly” antifreeze (propylene glycol). Each cup is covered with 1/2” mesh and flashing to keep out both vertebrates and rain.

© 2010, A.V. Evans

Thank you so very much to all the students who joined me on that wonderful day. Not only did you help get the job done, you also inspired me with your camaraderie, energy, and sense of purpose.

© 2010, A.V. Evans

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

Posted in Environment, Insects, Pests, True bugs, Winter with tags , , , , , on March 15, 2010 by Dr. Art Evans

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

WHAT’S IN YOUR BASEMENT?

Posted in Environment, Grasshoppers & crickets, Insects with tags , , on March 9, 2010 by Dr. Art Evans

By Arthur V. Evans

While moving some bags of potting soil on the front porch a few years back, I discovered a gathering of variously sized leggy and very nervous creatures. Their pale bodies, not quite reaching an inch in length, appeared to be brown banded, supported by long legs mottled with patches of gray and rust. Their long, hair-like antennae waved nervously about as I knelt down for a closer look. At first glance, they looked decidedly spidery in appearance. They scampered easily up, over, and around vertical surfaces of concrete, brick, and paneling and quickly disappeared into the nearby shrubbery. I had stumbled upon a congregation of camel crickets popularly known as greenhouse stone crickets, Diestrammena asynamora.

This handsome greenhouse stone cricket, Diestrammena asynamora, was photographed in my basement last fall. Our cats seem to thoroughly enjoy them and frequently leave maimed cricket bodies in conspicuous places around the house.

Greenhouse stone crickets are distinguished from other camel crickets in eastern North America by their decided preference for urban surroundings and a pair of small, closely set horns located between the bases of the antennae. Their long antennae—which may exceed three-times the body length—combined with long legs, may fool some people into thinking that they are spiders. In fact, some people call them “spider crickets.”

Their powerful jumping legs can launch them up to four feet in the air. Mature females have a long, swordlike egg-laying tube, or ovipositor that they use to deposit several hundred eggs in the soil in spring. The eggs take about two or three months to hatch. The young, wingless crickets strongly resemble the adults but are smaller in size. Once mature, the adults live for about a year. Greenhouse stone crickets overwinter as either nymphs or adults.

Greenhouse stone crickets belong to the family Rhaphidophoridae. Raphidophorids are commonly known as camel crickets because of their hump-backed appearance. They are also called cave crickets because they are often found living in and around the entrances of caves. However, they are equally at home in crevices, hollow trees, and basements, or under logs and stones. Strictly nocturnal, greenhouse stone crickets venture out during the day only when disturbed. Without wings or other sound-producing structures, these crickets never contribute to the evening chorus. However, some camel crickets are thought to drum their abdomens on the substrate in an effort to attract mates.

Some of the 200 or so species of camel and cave crickets known to occur in North America originally hail from other parts of the world. An immigrant from China, the greenhouse stone cricket first became established in the warm, moist greenhouses throughout much of Europe and North America, and is now cosmopolitan.

During heavy rains, or hot, dry days, greenhouse stone crickets will invade garages, sheds, and basements, often assembling by the dozens or hundreds. Indoors, the crickets are attracted to dark, humid spaces, such as those afforded by bathrooms and laundry rooms. Clothing and linens stored in these areas may be damaged if persistent populations of these crickets cannot find suitable plant food nearby.

Outdoors, they are commonly found on the ground, beneath stones and logs, or in piles of firewood. Areas overgrown with ivy and other ground covers provide excellent hiding places for them. Greenhouse stone crickets feed on living plants and small insects. In greenhouses, these crickets will eagerly consume seedling, flowers, seeds, or young leaves, but they seldom cause serious damage to plants. They will also scavenge other plant and animal materials.

As you read this, you can take comfort in the fact that right now, somewhere in the bowels of  your basement or elsewhere on your property, these sociable creatures are quietly taking refuge. Whether we like it or not, our steady supplies of food and water, served up in artificially warmed environments, have made it possible for these curious creatures to become a regular part of our lives.

©2010, A.V. Evans

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