Archive for the VCU Rice Center 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

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

HUBBARD’S ANGEL INSECT

Posted in Insects, VCU Rice Center with tags , , , on March 8, 2010 by Dr. Art Evans

By Arthur V. Evans

My step-son Graham Wilson and I drove out to the VCU Rice Center in Charles City County, Virginia this morning in search of insects to photograph. By late morning, the temperature was in the high 50’s and the only insect seen on the wing was a single mourning cloak. Undaunted, I began searching for snags and logs with loose bark.

With Graham looking on, I slowly peeled back a slab of bark from a large fallen oak. I soon caught a glimpse of several tiny, pale insects less than 1/8 inch (2.0-3.0 mm) long as they scurried about the smooth, moist patch of exposed wood. I immediately recognized the wingless, termite-like animals as angel insects, or zorapterans. They quickly scrambled to find a dark nook or cranny to escape the sudden invasion of light.

Hubbard's angel insect, Zorotypus hubbardi, is one of two species of zorapterans found in the United States.

Angel insects are not rare and are sometimes quite abundant locally. They simply escape attention because they are small, secretive, and easily overlooked. Adults are most active in spring and summer and are typically found in deciduous woodlands. Here in Virginia, I usually find them under the bark of rotten logs, often in association with moist accumulations of termite frass.

The order Zoraptera was proposed in 1913 by the Italian entomologist Filippo Silvestri. The name of the order is derived from the Greek words zoros (sheer or pure), a, without, and pteros (wing); winged zorapterans were discovered after the name of the order was proposed. Of the 32 species of angel insects known worldwide, most are tropical. Only two are found in the United States: Hubbard’s angel insect, Zorotypus hubbardi Caudell (eastern United States) and Snyder’s angel insect, Z. snyderi Caudell (southern Florida).

Hubbard’s angel insects are gregarious and live in small groups; isolated individuals are incapable of surviving for very long on their own. They are usually found under the bark of rotting logs, where they eat fungus, especially spores and the branching, threadlike fungal structures known as hyphae. Dead nematodes, mites, small insects and other minute arthropods are also scavenged when there is an opportunity. In the laboratory, angel insects thrive on a diet of yeast and crushed rat chow, as well as their own remains.

Angel insects spend much of their time grooming themselves or each other. They reproduce sexually or by parthenogenesis. Before mating, males court females by offering them droplets of fluid secreted by a special gland on their head. Receptive females mate for several days with the same or different partners. Soon they will lay batches of eggs, cover them with chewed bits of food, and watch over them for several weeks until they hatch. The larvae resemble small versions of the adults and molt four or five times before reaching maturity. The larvae are distinguished from the adults by their smaller size and eight-segmented antennae.

Most angel insects are pale, wingless, and blind. Their eyeless, triangular heads are equipped with chewing mouthparts. Adults have pair of antennae with nine bead-like segments. Their hind legs are equipped with bulging thighs armed with a row of small, sharp spines underneath. All six zorapteran feet are two-segmented, the first of which is very short.

Tough times as a result of overcrowding or dwindling food supplies trigger the production of eyed and winged males and females that soon take to the air in search of better living conditions. Their four transparent wings resemble narrow paddles and have few supporting veins. Although similar in shape, the forewings are distinctly longer than the hindwings. Zorapterans are often attracted to lights on warm nights. Like termites, they shed their wings easily upon entering a new log, leaving only four small stubs behind.

Zorapterans have stumped systematic entomologists for years in terms of trying to sort out their relationships with other insects. Unfortunately, their currently sparse fossil record has yet to shed any light on the subject. Originally considered the nearest relative of termites, zorapterans have since been allied with termites + cockroaches, earwigs, earwigs + cockroaches + mantids, thrips, or barklice.  Currently, they are considered as closely allied with another curious group of insects, the webspinners (Embioptera).

© 2010, A.V. Evans

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