A Natural History of the Central Appalachians

Chapter 10: Insects of the Central Appalachians

CHAPTER 10 INSECTS OF THE CENTRAL APPALACHIANS THE MAJOR DISTINGUISHING FEATURE of an insect is that it has six legs. Most adult insects are capable of flight, and this—coupled with their sheer abundance—makes them more conspicuous than any other group of invertebrates found in the Central Appalachians. Although most insects are terrestrial, numerous aquatic forms also exist, including some that are aquatic when immature but develop into terrestrial adults. It is impossible to do justice in a single chapter to the incredible assemblage of insects that can be found in the Central Appalachians. The main focus will be on taxonomic orders or representatives of an order that are of special interest from the standpoint of aesthetics, ecology, or economics. ORDERS OF INSECTS As will be clear to anyone with even a modest exposure to the study of insects (entomology), any consideration of insects begins with being able to assign a specimen to the proper taxonomic order. Although the average person would not be expected to know the formal names used by entomologists for the approximately thirty orders currently recognized, most people are able to distinguish among such insects as butterflies, bees, flies, beetles, and grasshoppers, each of which represents a different taxonomic order. For example, butterflies (and also moths) belong to the order Lepidoptera, bees to Hymenoptera, flies to Diptera, beetles to Coleoptera, and grasshoppers to Orthoptera. The members of each order are characterized by certain distinguishing features. Butterflies have large, often brightly colored wings and fly about in a conspicuous, fluttering manner; bees have membranous, usually transparent wings and are known to be able to sting; flies have prominent eyes, appear to have only one pair of wings (virtually all other winged insects have two pairs), and tend to be pests; beetles have wings hidden beneath a shell-like covering on the back, and larger examples fly very poorly; and grasshoppers have large hind legs and can jump. These features do not necessarily apply to all members of a particular order, and some examples of one order body, while most moths at rest spread their wings horizontally to the sides of the body or fold them longitudinally against the body. The first of these generalizations does not always hold true, and at least a few of the most interesting moths are active during the day. Such is the case for the bumblebee moth, which resembles a bumblebee in both appearance and behavior. This species, which is most likely to be encountered in old fields and other open areas throughout the Central Appalachians, produces the same sort of buzzing sound that one associates with bees and has an abdomen with yellow and black segments much like those of a bumblebee, along with wings that are mostly transparent (although the veins and margin are dark brown). The bumblebee moth beats its wings very rapidly to fly, another bee-like feature, and it hovers over a flower to feed. Upon seeing one for the first time, few people would think of this insect as a moth. Both butterflies and moths undergo complete metamorphosis, as do almost 90 percent of all insects, which means that may appear to have the features of an entirely different order. For example, some flies—hover flies, robber flies, and bee flies—resemble bees so much that even an entomologist might have to take a second look to make a correct identification (fig. 87). Nevertheless, the classification of insects into groups is generally useful, and representatives of each of the orders mentioned are common and often conspicuous inhabitants of the Central Appalachians. BUTTERFLIES AND MOTHS Butterflies are easily noticed, but the order to which the butterflies belong also includes the moths, which, although less appreciated by the average person, are much more numerous (worldwide there are about ten times as many species of moths as butterflies). Most people are aware that moths are usually active at night and are attracted to light, while butterflies are usually active during the day. Less appreciated, although just as apparent, is that most butterflies at rest hold their wings together vertically above the FIGURE 87 Hover fly, a true fly that closely resembles a bee in both appearance and behavior 167 10 INSECTS OF THE CENTRAL APPALACHIANS an individual goes through four stages—egg, larva, pupa, and adult—in its life cycle. By contrast, incomplete metamorphosis...