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Large and Unusual Insects Found in Virginia

ID

ENTO-148NP (ENTO-419NP)

Authors as Published

Authored by Eric Day, Lab Manager, and Theresa A. Dellinger, Diagnostician, Insect ID Lab, Department of Entomology, Virginia Tech

Introduction

Several different insects found in Virginia often cause concern due to their large size or coloration. For the most part, these insects are harmless curiosities of nature.

Dobsonflies

Dobsonflies, Corydalus cornutus, are found near rivers and streams. The adults are attracted to lights at night. The immature stage of this insect, called the hellgrammite, is aquatic and highly favored as fish bait. The wingspan measures 4-10 cm (1.5-4 inches) and the males have large but harmless mandibles that extend forward from the head (Fig. 1). The females have shorter, stouter mandibles that can give a painful bite if handled carelessly. 

Figure 1, Two adult dobsonflies with long, patterned wings extendeding from their bodies.
Figure 1. Adult male (top) and female (bottom) dobsonflies (Kansas Department of Agriculture, Bugwood.org).

Eastern Hercules Beetle

Adult eastern hercules beetles, Dynastes tityus, are sometimes found near lights at night and can measure over 4 cm (2 inches) long. The males have long projections on the head and thorax that are used to knock other males off trees but are otherwise harmless. The adult female is similar in size and color, but is hornless. The immature stage is a large white grub found inside oak and locust trees with heart-rot.

Figure 2, A large beetle with two long, stout horns extending forward from the body.
Figure 2. Male eastern hercules beetle (Allen Bridgman, SC Department of Natural Resources, Bugwood.org).

Luna Moth

Luna moths, Actias luna, are large green moths that are found near houses, often on a screen or wall near an outside light. The moth can have a wingspan of up to 10 cm (4 inches) with noticeably long tails on the hindwings (Fig. 3). The larva, which is a large caterpillar, feeds on the leaves of a variety of hardwood trees (Fig. 4).

Figure 3, A showy, large moth with long tails extending from the hind wings rests on a twig.
Figure 3. Adult luna moth (Arnold T. Drooz, USDA Forest Service, Bugwood.org).
Figure 4, A large, stout caterpillar with a noticeably segmented body grasps a twig.
Figure 4. Luna moth caterpillar (Gerald J. Lenhard, Louisiana State University, Bugwood.org).

Cecropia Moth

Cecropia moths, Hyalophora cecropia, are another large moth with a wingspan of up to 10 cm (4 inches) (Fig. 5). They are also attracted to porch lights, and are often found on screens and walls the next morning. The caterpillars feed on the leaves of various hardwood trees (Fig. 6). 

Figure 5, A large, colorful moth.
Figure 5. Adult cecropia moth (Pennsylvania Department of Conservation and Natural Resources – Forestry, Bugwood.org).
Figure 6, A large, stout caterpillar with numerous knobby growths feeds on a leaf.
Figure 6. Cecropia moth caterpillar (John Ghent, bugwood.org).

Eastern Eyed Click Beetle

Adult eastern eyed click beetles, Alaus oculatus, have a pattern on their thorax that resembles eyespots and is thought to be a defense against attack by birds (Fig. 7). Despite some folklore accounts, these eyespots do not glow in the dark. Adults measure about 2.5-5 cm (1-2 inches) long. The grub stage lives in rotting trees and is harmless. 

Figure 7, An adult click beetle with two spots resembling large eyes on the pronotum.
Figure 7. Eyed click beetle (Whitney Cranshaw, Colorado State University, Bugwood.org).

Dragonflies

Dragonflies can have a wingspan of 7-10 cm (3-4 inches) and are found mostly near water, but also in fields and woods (Fig. 8). Adults feed on insects they capture in flight. Males fight for the best sites near water, where the females will lay their eggs. The immature stages are aquatic. Dragonflies are also known in folklore as “snake doctors” due to the belief that they would help injured snakes. 

Figure 8, A dragonfly rests on a twig with its distinctly patterned wings extended from its body .
Figure 8. Adult dragonfly (David Cappaert, Bugwood.org).

For more information on other unusual insects, see also the Virginia Cooperative Extension fact sheets on Velvet Ants, Giant Resin Bee, and the Wheel Bug.

Revised 

Theresa A. Dellinger, January 25, 2021.


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Publication Date

March 2, 2021