Family gryllidae-crickets

Дата канвертавання21.04.2016
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In this family only the tree crickets (Walker 1962) affect forest trees ; none is a forest pest. The snowy tree cricket, Oecanthus fultoni Walker, is an example. It is transcontinental. The adults are greenish white and have long, slender antennae and long hind legs. Forewings of the males are paddle-shaped and lie horizontally over the abdomen. This species lives in the crown of orchard trees and open-grown forest trees such as Garry oak and Oregon ash. The eggs are laid in slits in small branches where they overwinter. There is one generation annually.


The members of this family have long antennae, often longer than the body. The eggs are laid singly or in rows, usually on vegetation.

The Mormon cricket, Anabrus simplex Haldeman (Wakeland 1959) occurs in dryland areas of Western States and Provinces, excepting most of California, Arizona, and New Mexico. Two other species of Anabrus are similar in appearance and habits. Since pioneer days, A. simplex has been a major pest of agricul­tural crops. During heavy migrations, it occasionally invades and damages fringe-type ponderosa pine. Invasions are soon over and the only evidence is the tattered remains of the chewed foliage and small branches (fig. 23). Damage of this type has occurred in Oregon. The adults are yellow, green, brown, or black, wingless, heavy-bodied insects 35 to 45 mm long.


The walkingsticks and allies are large, generally slender and twiglike, sometimes leaflike, mainly tropical, plant-feeding insects. They are few and of little consequence in western forests.


The walkingstick, Diapheromera femorata (Say) (Wilson 1964) (fig. 24), is primarily an eastern insect but ranges into New Mexico and Arizona. It is a defoliator of hardwoods. The adult is wingless, about 60 to 80 mm long, and twiglike in shape and color. Outbreaks tend to be local. The eggs are black, laid singly, and literally rain down during heavy outbreaks.


Termites (Ebeling 1968 ; Kofoid et al. 1934 ; Krishna 1966 ; Snyder 1949a, 1956, 1961; Weesner 1965) are a large and destruc­tive group of insects which feed upon cellulose, principally in


F-521905 FIGURE 23. - Needles and twigs of young ponderosa pine damaged by the Mor­mon cricket (Anabrus sim­plex).


FIGURE 24.-Adult male walkingstick (Diapheromera femorata) on twig.


wood. Often they mine so extensively that only a paper-thin outer shell of wood remains. In the forest, they commonly occur in felled trees, in snags, and in stumps or other sections of dead or decay­ing wood. Insofar as they reduce forest debris they are beneficial, but some are very destructive to buildings, telephone poles, fences, furniture, and other wood products. Rarely they injure or kill trees. The group as a whole is most abundant and most de­structive in the Tropics, and in the United States causes most damage in the warmer southern latitudes. Numerous species are found in the Southwest and southern California. Only a few range into the Pacific Northwest and Northern Rocky Mountain Region. Four families contain species that may be encountered by western foresters. All species presently found in the West are native.

Termites live in colonies in wood or in the ground and expose themselves to light only when in the winged adult stage (Snyder 1949b). Colonies consist of several forms or castes, such as work­ers, soldiers, primary and secondary reproductives, and nymphs. Termites, sometimes called "white ants," are frequently confused with true ants but are quite different in appearance and habits. Unwinged termites are soft, whitish, and broad-waisted in con­trast to ants, which are tough-surfaced, brownish to black, and narrow-waisted. Winged termites usually are brownish to black, as are ants, but differ in being broad rather than narrow-waisted and in having all four wings of similar size and shape rather than dissimilar (fig. 25). Their excavations in wood are hollow, com­pletely enclosed, more or less longitudinal cavities, in which some species deposit small pellets of excrement. Drywood termites often expel the pellets through surface openings, but no termites expel boring dust as do carpenter ants and some other wood borers.

Prevention is the best approach to termite control. In the case of ground-inhabiting termites, prevention measures consist of


FIGURE 25.-Example of winged termite, showing uniformly broad body and similarity in size of fore-wings and hindwings; body 8 mm long.


isolating wood from contact with the ground and in using wood treated with termite-repellent chemicals. When wood is found to be infested by insects, the first step is to determine whether they are termites or other insects. If termites are present it is recom­mended that the reader consult one or more of the many publica­tions on control of these insects (Ebeling 1968, Johnston et al. 1972, Snyder 1966). Control measures should be thoroughly applied and should include structural changes to prevent reinfestation when feasible.


In the West, the Hodotermitidae contains one genus, Zooter­mopsis (Castle 1934), with three species. They are the largest of the western termites. Known as dampwood termites, they live in damp, usually rotten wood, and do not require contact with the ground. Often they colonize hi houses and other structures made of wood. They cause some damage but their presence is more sig­nificant as an indicator of rot. Insecticides will kill them, but will not solve the basic rot problem. Untreated wood should be kept off the ground to prevent it from becoming damp, and structural changes should be made to eliminate excessive moisture which causes the rot and attracts the termites.

Zootermopsis colonies contain reproductives, soldiers, and nymphs (fig. 26). The nymphs are dirty white, 3 to about 15 mm long and resemble the worker caste of more highly evolved ter­mites. The fully developed soldiers are light brown, 10 to 20 mm long and have a large head armed with a pair of long, black, toothed mandibles. Winged reproductives (fig. 26A) are light cinnamon-brown and have dark brown, heavily veined, leathery wings about 25 mm long, which are readily shed. In northern California and western Oregon and Washington, where Zooter­mopsis is most abundant, the winged forms commonly take flight on warm sultry evenings in August, September, and October to mate and found new colonies.

The Pacific dampwood termite, Zootermopsis angusticollis (Hagen) (Castle 1934, Goulding and Every 1964), ranges from southern British Columbia through Oregon, Washington, and California into Mexico. It is the common dampwood termite of coastal forests where it sooner or later colonizes most dead and down trees and untreated wood products in contact with the ground.

Z. nevadensis (Hagen) (Castle 1934) ranges from southern British Columbia to central California and eastward into Montana. In general it occurs in cooler, drier, and higher areas than does Z. angusticollis which it closely resembles in appearance and



FIGURE 26.-Pacific dampwood termite (Zootermopsis angusticollis) : A, Winged reproductive, body 10 mm long; B, nymph, 8 mm long; C, soldier, 18 mm long.

habits. Z. nevadensis is somewhat smaller and darker in the winged stage.

Z. laticeps (Banks) (Castle 1934) is a little-known species that occurs in southern Arizona and New Mexico.


The species of Kalotermitidae (Ebeling 1968, Light 1934b, Weesner 1965), with one exception, live in wood and as a group are known as drywood termites. They are generally larger than subterranean termites and smaller than dampwood termites. Typi­ cal drywood termites attack and live in sound dry wood above ground, hence prevention and control measures differ from those for subterranean termites (Snyder 1966). Structural methods of preventing attacks by drywood termites are relatively less effec­ tive, thus direct control by chemicals is more frequently needed.

Incisitermes [Kalotermes] (Light 1934b) is a sizeable genus of typical drywood termites. Several species occur in the Southern United States. In the West, the principal one is the western dry- wood termite, I. minor (Hagen) (Ebeling 1968, Harvey 1934). It occurs in California, Arizona, and Mexico. This termite attacks sound dry wood such as the dead branches of trees, the upper portions of buildings, and furniture. Colonies are small and consist of reproductives, soldiers, and immature forms (nymphs), but no true worker caste (fig. 27A, B) . Fecal pellets (fig. 27C) sifting



FIGURE 27.-Western drywood termite (Incisitermes minor) : A, Winged re­productive, length to wing tips, 18 mm; B, soldier, 14 mm long; C, fecal pellets.

down from infested wood and the swarming of winged forms are the usual signs of attack. Flight occurs at temperatures above 80° F on sunny days in September and October in southern Cali­fornia. The body of the winged adult is black and the head, reddish brown. The third segment of the antenna of the soldier is about as long as the next four segments combined.

Marginitermes hubbardi (Banks) (Light 1934c, Weesner 1965) occurs in Arizona, southern California, and southward in Mexico. It is a typical drywood termite with habits similar to Incisitermes minor and causes similar damage to buildings and wood products. The body of the winged adult is yellowish. The third segment of the antenna of the soldier is nearly as long as the other segments combined.

Paraneotermes contains one species, P. simplicicornis (Banks) (Light 1934d). This termite, in contrast to other Kalotermitidae, lives in the ground much as do subterranean termites. It occurs in desert areas from southern California to Texas and southward in Mexico. The body of the winged adult is dark brown. The third segment of the antenna of the soldier is about the same length as the fourth. P. simplicicornis normally mines and feeds in the dead roots, lower stems, and fallen branches of desert trees and shrubs such as mesquite. At times it damages untreated poles and posts by mining them just below ground line. It also is recorded as damaging living trees.


Rhinotermitidae (Ebeling 1968, Weesner 1965) contains the subterranean termites which are the termites that cause greatest damage in the West. Three genera are of principal concern. Sub-


terranean termites develop and maintain their colonies in the ground, but often feed above ground by extending their galleries in wood or by building earthen tubes over obstructions to shield themselves from desiccation and light. Their galleries are open except for some chambers plastered with a mixture of excrement and uneaten particles of wood. Prior to structural failure of infested wood, the principal signs of attack by subterranean termites are the earthen tubes and the seasonal swarming of winged reproductives.

Reticulitermes (Ebeling 1968) contains several species, two of which are widely destructive to man-made structures in the West. They feed principally on the springwood and leave the harder summerwood in ribbons (fig. 28).

The western subterranean termite, Reticulitermes hesperus Banks (Pickens 1934a) is the major termite pest from southern British Columbia through Washington and Oregon to central California. Colonies consist of workers, reproductives, and soldiers (fig. 29) . The workers are grayish white and are about 5 mm long when full grown. The soldiers are of similar color, somewhat longer, and have larger heads and more prominent mandibles. The winged adults are slender, cylindrical, dark brown to black, and about 4 mm long, exclusive of the wings which are translucent and of equal length. Following the first heavy rains in fall, the winged forms emerge en masse, mate, shed their wings, and found new colonies. Once established, a colony may continue to develop for years and attain a population of several hundred thousand. This termite often builds earthenlike tubes over concrete foundations to get to wood above but must retain contact through them to the

F-521907 FIGURE 28.-Cross section of wood damaged by western subterranean termite (Re- ticulitermes hesperus), showing preference for springwood.

ground (fig. 30). Damage can best be prevented by a combination of structural and chemical means (Ebeling 1968, Johnston 1965, Johnston et al. 1972) .

The aridland subterranean termite, Reticulitermes tibialis Banks (Pickens 1934b) occurs in California, the Great Basin, and the southern Rocky Mountain States. Its appearance, habits, potential for causing damage, and control are similar to R. hes­perus. The ranges of these two species overlap only slightly. Physi­cally, they differ most markedly in that the head of the soldier of R. tibialis is short, broad, and dark colored in contrast to the long, narrow, and pale head of R. hesperus.

Coptotermes (Light and Pickens 1934) is a tropical genus, one species of which has become established in the United States.

The Formosan subterranean termite; Coptotermes formosanus Shiraki (Baker 1972) is a destructive oriental species introduced into Hawaii, Texas, Louisiana, and South Carolina. It is a poten­tial invader of the warmer portions of the Pacific coast. Compared with Reticulitermes,. C. formosanus is somewhat larger in all stages ; the head of the soldier is oval rather than oblong and rectangular; the wings are hairy rather than hairless ; and flight is at night rather than in the daytime. C. formosanus builds an earthenlike nest, usually in the ground, and requires a high level of moisture.

Heterotermes is a tropical genus, one species of which ranges northward into the Southwestern United States. The habits are similar to those of Coptotermes.


FIGURE 29.-Western subterranean termite

(Reticulitermes hesperus) : A, Winged re-

productive, length to wing tips, 10 mm; B,

soldier, 7 mm long; C, worker, 5 mm long.


FIGURE 30.-Earthenlike tubes built over cement foundation by western sub­terranean termite (Reticu­litermes hesperus).

Heterotermes aureus (Snyder) (Pickens and Light 1934) occurs in southern California and Arizona, causing considerable economic loss. It resembles species of Reticulitermes but the winged adults are pale rather than black.


The Termitidae (Light 1934a, Weesner 1965) is a large family worldwide. In the United States it consists principally of ground- dwelling termites of the genus Amitermes, which occur in the Southwest. They cause little damage to wood. Their earthen tubes often cover desert vegetation, including range grasses.



This order (Chapman 1930), sometimes called Corrodentia, con- tains small insects of no economic significance in the forest. Of the


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