Archive for the Environment Category

THE FOREST CATERPILLAR HUNTER, Calosoma sycophanta, IN VIRGINIA

Posted in Beetles, Environment, Insects with tags , , , , , , , on February 24, 2010 by Dr. Art Evans

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

NATURAL HISTORY COLLECTIONS INFORM PAST, PRESENT, FUTURE

Posted in Education, Environment, Musings with tags on May 26, 2009 by Dr. Art Evans

I recently attended a behind-the-scenes tour of the National Museum of Natural History, part of the Smithsonian Institution’s core network of museums. Although I have worked with museum collections for years, I still had that sense that I was in a scene from Citizen Kane or Indiana Jones as I wandered the labyrinth of hallways and dimly lit passages lined floor-to-ceiling with stacks of cabinets and shelves chock full of specimens from around the world.

Yet, it is sobering to note that over the years natural history collections are on hard times as funding and public interests have waxed and waned. Many universities and smaller museums have divested themselves of their collections of pressed, impaled, pickled, stuffed, and skinned specimens of plants and animals. Administrators, policy makers, and the scientists among them are hard pressed to justify the “care and feeding” of collections, preferring instead to direct ever-shrinking resources into other projects that are more likely to attract supplemental funding. However, as support for collecting and collections dwindles, the need for the information they provide continues to increase.

Biodiversity research has long been the primary motivation behind the use of natural history collections. However, the traditional uses of these collections for the purposes of identification, the study of relationships, and evolutionary biology through the examination and comparison of specimens are only part of the story. These very same specimens are now useful tools for tracking changes in populations and habitats over time.

Like “biological filter paper,” natural history specimens can reveal past and present environmental conditions. Chemical analyses of feathers, hair, bone, muscles, blood, stomach contents, and vegetative tissues are now used to trace migratory movements, uncover feeding behaviors, reveal changes in habitats over time, and determine the epidemiology of diseases that affect animals and crops.

For example, analysis of old egg specimens demonstrated the devastating effect DDT had on bird reproduction and ultimately resulted in legislation that banned its use in this country. Similar studies were conducted to trace the increase of harmful mutations after nuclear accidents (remember Chernobyl?), the origin and movement of crop diseases (think Irish potato famine), and the rise of mercury levels in marine animals.

I have always thought of natural history collections like libraries, only the references contained therein are in the form of specimens. Like books, carefully prepared collections provide unique information that links identity, geography, and history. This is the very information that conservationists rely on to inform their decisions regarding the rarity of species and the potential impacts of climate change on those species.

Like a library, the relevance and vitality of natural history collections is maintained through new acquisitions in the form of specimens gathered during ongoing field surveys. Data gleaned from both rare and common species will better inform scientists and policy makers to address the inevitable challenges wrought by shifting populations and habitats. But will we as a society have the foresight and will to support such endeavors?

©2009, A.V. Evans

THE MAN AND HIS MILLIPEDES

Posted in Environment, Millipedes with tags , on May 7, 2009 by Dr. Art Evans

The Buffalo Mountain Natural Area Preserve in southeastern Floyd County is a biological hot spot in Virginia. This 1,000 acre preserve, managed by the Department of Conservation and Recreation’s Natural Heritage Program, boasts six natural communities and supports a plethora of organisms. The mountain summit and its glades are home to at least 17 rare plant and invertebrate species.

In September of 2007, I paid a visit, along with my colleague Anne Chazal, to the northern flank of Buffalo Mountain to look for invertebrates. In spite of cool and dry conditions, our searches revealed several species of millipeds in and under some rotten logs.

Of the estimated 12,000 of millipeds known worldwide just over 900 species live in the the United States and IMG_2763Canada. About 200 species are found in Virginia, nearly half of which have never been formally described and catalogued by scientists.

The study of millipeds has long been undervalued and underfunded by government and private agencies because millipeds do not destroy crops or spread disease. However, their habits, defensive behaviors, distributions, and critical role as forest decomposers make millipeds ideal subjects for scientists studying biodiversity, evolution, biogeography, and forest ecology.

Most millipeds eat rotting vegetation rather than living plant tissue. Like earthworms, they ingest soil and extract organic materials for nutrition. The bits of leaves and other plant materials that make up their fecal pellets provide ample surface area for fungi and bacteria to become established and speed up the decomposition of plant materials.

Typically slow and usually unable to bite, pinch, or sting, millipeds are hardly defenseless. Their hardened exoskeleton affords them some protection, especially those species that coil up their bodies to protect their vulnerable underbellies.

When attacked, many millipeds exude mildly fruity to downright smelly fluids from pores located along the sides of their bodies. This chemical cocktail contains repellent compounds that are sometimes toxic to small soil-dwelling animals, as well as effective antifungal agents.

Identifying millipedes can be difficult. Fortunately, one of the world’s leading experts on millipedes works just down the road at the Virginia Museum of Natural History in Martinsville. Anne and I carefully bagged up our many-legged catch, along with some cool and moist bits of punky wood, moss, dead leaves, and lichens, and headed east on Highway 58.

IMG_8934

©2008, C.C. Wirth

We arrived to find Dr. Richard L. Hoffman in his lab surrounded by jars and vials of preserved specimens, most of which were millipeds. Thanks to his efforts, the museum houses one of the world’s largest and most important milliped collections.

Dr. Hoffman recognized the first two Buffalo Mountain species immediately, while another two required a brief inspection through a binocular microscope before their identities could be confirmed.

His seminal work on the classification of millipeds nearly 30 years ago set the standard for scientists studying these endlessly fascinating animals. Dr. Hoffman has also made substantial contributions to our knowledge of reptiles, amphibians, and numerous groups of invertebrates in Virginia, especially beetles and true bugs.

Just a week after our visit, Dr. Hoffman was feted with a reception, milliped symposium, and banquet hosted at the Virginia Museum of Natural History in celebration of his eightieth birthday and his lifelong scientific achievements.

The list of scientists, students, and other well-wishers at the fete read like a “Who’s Who” of North American milliped workers and field zoologists, several of whom specifically attributed their choice of career paths to Dr. Hoffman’s influence, support, and guidance.

Dr. Hoffman ascribes his success over the years to a combination of factors, including supportive parents, growing up in a place of incredible natural beauty, freedom to explore nature as a youth, being in the right place at the right time, and the continual support of family, friends, and colleagues.

Showing no signs of slowing down even after his recent retirement, Dr. Hoffman is still collecting, writing, and mentoring. Ever curious and insightful, he continues to enlighten and inspire all those who have had the pleasure and good fortune to know him, this writer included.

My thanks to Chris Wirth for the image of me and Richard Hoffman.

©2009, A.V. Evans

OUR SEAS OF PLASTIC

Posted in Aquatic, Education, Environment, Musings on March 30, 2009 by Dr. Art Evans

I want to bring to your attention the efforts of a former colleague of mine at the Natural History Museum of Los Angeles County, Dr. Marcus Eriksen. Marcus is a man of many talents: scientist, educator, author, conservationist, and adventurer. As the Director of Research and Education at the Algalita Marine Research Foundation , he is actively involved in the protection of marine watersheds through research, education, and restoration. Marcus and the AMRF team are at the forefront of studying the massive accumulation of plastic debris in our oceans and the impact of this pollution on marine life and the human food supply. Hundreds of millions of tons of bottles, bottle caps, cigarette lighters, bags, food containers, toys and other plastic items are washed through our watersheds and into our oceans each year.

Phase I of this AMRF study, dubbed “Message in a Bottle,” began with a research voyage into the North Pacific Gyre to investigate plastic pollution that has been dubbed the “Great Pacific Garbage Patch.” In Phase II, Marcus and a colleague sailed 2,600 miles from Los Angeles to Hawaii last summer on a raft made from 15,000 plastic bottles to raise awareness of plastic marine debris fouling our oceans.

Phase III begins on Saturday, 4 April when Marcus and his fiance Anna ride their bicycles 2000 miles from Vancouver, British Columbia to Tijuana, Mexico. Along this route they will distribute samples of plastic debris collected from the North Pacific Gyre to legislators, educators, and organizations to raise awareness of plastic debris in our oceans.

The problem is that plastic is designed to last forever, yet we use it regularly to make products that are thrown away. Although recycling is effective for paper, metal, glass, and other materials, it is not the answer for plastics. And as a petroleum product plastic, like our consumption of gasoline, keeps us dependent upon foreign sources of oil.

The “Message in a Bottle” project has encouraged me to rethink how I use plastic products at home and in the workplace. My first small step into this brave new world is to avoid purchasing or using drinks of any kind in plastic bottles, especially water. Then I am going to try to encourage my favorite take-out eateries to start using more eco-friendly to-go containers. A recent trip to the grocery store was sober reminder of just how pervasive plastic is in our culture, but there are lots of creative people out there who are coming up with practical and interesting ways for reusing and recycling these containers.

If we all do our part, and encourage our colleagues, clients, and visitors to do the same, we can make a difference and help to reduce the amount of plastic debris that finds its way into our oceans!

LEAVE NO CHILD INSIDE

Posted in Education, Environment on February 9, 2009 by Dr. Art Evans

The single most important ingredient that ignited my lifelong passion for insects and all natural history was…freedom.

Supportive parents, teachers, librarians, and scientists all fostered my interest in insects and natural history, but it was the freedom to explore and discover nature at my own pace that really made the difference.

As a youngster, I spent many glorious hours on end wandering along trails, hiking up canyons, mucking about in streams, turning over rocks, examining flowers, and peeling back bark.

These early explorations taught me a great deal about the natural world. They also rewarded me with invaluable self-knowledge that continues to serve me well today—that the outdoors is my own personal refuge.

Sadly, unstructured time for most children has become a thing of the past. Recess time outside has been eliminated from many elementary schools. Overburdened with homework, sports, and other structured activities, children today have little time or inclination to just step out outside and ‘be.’

Freedom to explore, to get dirty, and to be ‘human beings’ instead of ‘human doings’ has all but vanished for children. Studies show that their outdoor time is down by 50% when compared to that of their parents and grandparents.

Cheryl Charles, president of the Children and Nature Network, notes that during the past two or three decades, well-intentioned parents have replaced nature with scheduled activities and events. She notes that technology, such as computers, iPods, television, etc., have their place but are consuming a disproportionate amount of their children’s time.

Parents are justifiably worried about the safety of their children, but the Internet has proven to be more dangerous than the outdoors, which is even more reason to encourage children to spend more time in “green space” than with “screen space.”

As human beings, we need the colors and rhythms that only nature can provide. The sights, smells, and sounds of nature provide us with vivid of memories that last a lifetime.

Years from now it is these shared experiences outdoors—not those in front of a television or computer screen—that will help us and our children to recall family and friends long since gone.

The disjunction between children and nature is not only to their detriment, but also to the detriment of nature itself. After all, we only save what we love and we love only what we know.

According to researchers at Cornell University, children who spend time in the wild fishing and camping before the age of 11 are more likely to grow up to be environmentally-minded and committed as adults.

The very notion of “leave no child behind” must begin with the basic concept of “leave no child inside.” The next time you really want to do something for a child, spend time with them outdoors. Just go out into the yard, or visit a city, state, or national park. It will do you both a world of good.

To learn more about movements to reconnect children with nature visit < http://www.cnaturenet.org/> and the National Wildlife Federation’s “Green Hour” program <www.GreenHour.org>.

©2007, A.V. Evans

%d bloggers like this: