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Macromoths of Northwest Forests and Woodlands

Macromoth Family Notes


Macromoths representing 12 families of Lepidoptera are commonly collected in the Pacific Northwest. These families are briefly described here. The numbers represent an estimation of the number of species in each family as they occur in the Pacific Northwest. These numbers are estimates because of the dynamics of name changes and recognized species status as well as incomplete species lists for the Pacific Northwest.


ARCTIIDAE - the tiger moths; photographs 1-16.

30 species. Tiger moths exhibit a wide range of colors and patterns of markings. Some species have immaculate wings while others show large spots or extensive criss-crossing bands. The adults of most species fly at night and are readily attracted to light; however, many of the species will be seen flying during the day. In fact, species of arctiids represent a large portion of the day-flying moths. Caterpillars of some of the species are called woollybears because the typical arctiid caterpillar has a dense coat of long hairs, giving the caterpillars a woolly appearance. Among the species of arctiids, caterpillars may feed on the foliage of conifers, Lophocampa argentata; flowering trees and shrubs, Lophocampa maculata; or herbs, including grasses, Cisseps fulvicollis. Nearly all species overwinter in the caterpillar stage. As previously mentioned many of the arctiids fly during the day. One of the day flying species is the cinnabar moth, Tyria jacobaeae, which was intentionally introduced as a biological control agent because the caterpillar feeds on flowers and leaves of the noxious weed tansy ragwort (Senecio jacobaea). Lophocampa argentata typically exhibits a short peak flight period, at any one site lasting perhaps 15 to 20 days within which time a single ultraviolet light trap may collect an excess of 200-300 individuals per night, demonstrating that this species is very abundant but short-lived as an adult. Hyphahtria cunea, the fall webworm, is a notorious pest of deciduous trees, including ornamental and orchard species. The Arctiidae of North America are well illustrated in Covell (1984).


DIOPTIDAE - the oak worm moths; photograph 17.

1 species. Phryganidia californica occurs in forests and woodlands containing live oaks, such as Quercus chrysolepis, and chinquapin, Chrysolepis chrysophylla, upon which the caterpillars are leaf feeders. Caterpillars overwinter and on warmer days may feed thus indicating the need for an evergreen host such as live oaks and chinquapin. The species is considered a pest due to occasional episodes of severe defoliation of the host plants. The species may fly at night but is not strongly attracted to light. Also, moths can be found flying during the day.


DREPANIDAE - the hook-tip moths; photograph 18.

2 species. Drepana arcuata is common, and Drepana bilineata is uncommon. The adults fly at night and are readily attracted to light. Caterpillars feed on the foliage of alder (Alnus) species.


LASIOCAMPIDAE - the lappet moths; photographs 19-21.

6 species. The lappet moth body is notably hairy and when at rest they typically hold their wings over the back of their body in a tent-like fashion rather than flat. Colors and markings on the forewings and hindwings of lappet moths do not create strongly contrasting or intricate patterns. The adults fly at night and are readily attracted to light. Lappet moths do not have functional mouthparts and therefore do not feed. Caterpillars of some of the species in the genus Malacosoma are called tent caterpillars because they spin silken tents within which the caterpillars spend most of their time. Caterpillars of lasiocampids may be found feeding on the foliage of conifers, Tolype distincta, or flowering trees and shrubs, Phyllodesma americana and Malacosoma californicum. There are three species of Malacosoma, M. californicum, M. disstria, and M. constrictum, in the Pacific Northwest, each of which is best identified in the field by the caterpillar. Phyllodesma americana is readily distinguished by the brick red color of the forewings and hindwings in combination with the scalloped outer edge that is very obvious when the adult is at rest. Similarly, Tolype distincta is readily distinguished by the hues of white and silver-gray. Franclemont (1973) provides detailed illustrations to the lappet moths of North America.


LYMANTRIIDAE - the tussock moths; photographs 22-26.

8 species. The adults of most species fly at night and are readily attracted to light; however, some of the species will be seen flying during the day, such as Orgyia antiqua and Orgyia pseudotsugata. Females of the two species just mentioned as day flyers are wingless and cannot fly, instead energy and body mass are conserved for the production of eggs. Caterpillars in a majority of the species feed on the foliage of conifers, Dasychira grisefacta and Orgyia pseudotsugata; or flowering trees and shrubs, Dasychira vagans and Leucoma salicis. Also, numerous species are considered pests, the most famous being the gypsy moth, Lymantria dispar (not illustrated here). The gypsy moth has not established permanent populations in the Pacific Northwest but it has created problems when accidentally brought into western North America. An infestation of the gypsy moth can result in an eradication project involving pesticides that in turn may have ecological impacts on other Lepidoptera species (Miller 1990a,b). Orgyia pseudotsugata is a native pest of conifer forests. Ferguson (1998) provides detailed illustrations and references to the tussock moths of North America.


GEOMETRIDAE - the geometer moths; photographs 27-106.

400 species. This family is second to the noctuids in containing the most species of Lepidoptera in the Pacific Northwest. The body of geometer moths is thin and more fragile looking than in other macromoths. The forewings and hindwings are broad relative to body size, and flight is typically slow with the beating wings discernible while the moth is in flight. The adults of most species fly at night and are readily attracted to light. Very few species, notably Rheumaptera subhastata and Mesoleuca gratulata, will be seen flying during the day. Females of some species are wingless and cannot fly, for instance Operopthera bruceata and Operopthera danbyi. In some males the antennae are pectinate, see Protoboarmia porcelaria or Drepanulatrix foeminaria. The general condition is to have filiform antennae in both sexes. Caterpillars are called inchworms because they possess prolegs only on the sixth and tenth abdominal segments, requiring the abdomen to bend upward resulting in the body looping forward as the caterpillar is walking. The caterpillars will often wave their body in the air while remaining attached to the substrate by their abdominal prolegs or the caterpillars will remain motionless for hours and may match their surroundings so well that the normal vertebrate eye cannot readily see them.

Many species have caterpillars that feed on the foliage of conifers, in which case the host is usually a range of species in the Pinaceae, but for a few moths a species in the Cupressaceae may be the primary host plant. A majority of the inchworm species feed on the foliage of flowering trees and shrubs, less frequently so on herbaceous plants. Numerous species are considered pests: Lambdina fiscellaria may defoliate vast areas of oak (Quercus) and chinquapin (Chrysolepis chrysophylla); Sabulodes aegrotata and Operopthera bruceata may feed on ornamentals and orchard crops. Certain of the geometrid genera in the Pacific Northwest are particularly diverse or illustrate interesting evolutionary trends. Species of Eupithecia are difficult to identify and may be most easily diagnosed under field conditions according to the host plant of the caterpillar. All species of Drepanulatrix feed on various species of Ceanothus, and 10 of the 11 species found in North America are endemic to the western United States. Ferguson (1985) provides detailed illustrations and references to the green geometers, Geometrinae, of North America.


NOCTUIDAE - the moths of cutworms, semi-loopers, and underwings; photographs 107-218.

850 species. This family contains the highest number of species among all families of Lepidoptera in the Pacific Northwest. Overall, species of noctuids range from very small, Nola minna with a wingspan of 2.0 cm, to relatively large, Catocala ilia with a wingspan of 7.9 cm. Similarly, the noctuid moths exhibit a broad array of colors and markings but generally the forewing and hindwings and bodies consist of varying hues of white, silver, gray, tan, brown, and black. Some will show green, Feralia, or orange to red as in Xestia oblata and Mesogona rubra. The moths of most noctuid species fly at night and most species are readily attracted to light. Certain species, such as Oncocnemis dunbari, will rarely show up at lights at night, yet collections of caterpillars from the foliage of ocean spray (Holodiscus discolor) suggest individuals of the species are very abundant. A few species of noctuids such as Alypia langtoni and Schinia walsinghami have day flying moths. The caterpillars in a majority of the species feed on the foliage of flowering trees, shrubs, or herbs. A few species of Syngrapha and Panthea portlandia have caterpillars that feed on the foliage of conifers, primarily species of Pinaceae. The feeding site of the caterpillar may differ according to species, in some species such as Papaipema insulidens caterpillars feed on roots or inside stems. Numerous species are considered pests of agricultural crops but none are considered chronic pests of woodlands and forests.

Certain of the noctuid genera in the Pacific Northwest are particularly diverse or illustrate interesting evolutionary trends. The Plusiinae, Eosphoropteryx thyatyroides, Autographa and Syngrapha are a group of noctuids called the semiloopers because the caterpillars are superficially similar to inchworms (Geometridae). The species of semiloopers are characterized by the shape and color of the stigma on the forewing. Euxoa is a genus of cutworms with many species where the caterpillars dwell in the soil and come to the surface to feed on stems and low leaves of herbaceous vegetation. Some of the species of Orthosia and Feralia are among the first moths to fly in the early spring and serve as a signal that winter is over and the season for field studies has begun. Underwing moths, of the genus Catocala, are among the largest noctuids and are characterized by contrasting colors of orange, red, or white with black markings. Illustrated references to the noctuids of North America have been published by Eichlin and Cunningham (1978), Lafontaine (1987), Lafontaine and Poole (1991), Poole (1995), and Lafontaine (1998).


NOTODONTIDAE - the moths of prominents; photographs 219-230.

20 species. The prominents of North America are not well represented in the Pacific Northwest, with only 20 of the 136 species known to occur in the United States and Canada. The adults fly at night and are readily attracted to light. The caterpillars typically feed on the foliage of flowering trees and shrubs. On occasion Schizura concinna may be a pest on ornamental trees and in orchards.


SATURNIIDAE - the silk moths; photographs 231-235.

12 species. The forewing and hindwings of silk moths are very large with wingspans extending to 10 or 15 cm in many of the species. Accordingly the wingbeat of most silk moths is relatively slow, each beat easily seen much like that of most butterflies. Wing colors and markings typically occur in distinct and sometimes intricate patterns, making identification of certain species a simple matter; however, many silk moths are known to have hybrid populations in areas where two closely related species can interbreed. The adults of most species fly at night and are readily attracted to light. A few species, notably Hemileuca eglanterina and Saturnia mendocino, will be seen flying during the day. Antennae of silk moths are unique in their morphology of being branched, similar to a fern frond, two or four times. The branched antennae are particularly noticeable in the males. The adults possess atrophied mouthparts and thus do not feed and typically are not long-lived.

Caterpillars are called silkworms but are not the silkworm of commercial silk production. For most species the caterpillars feed on the foliage of flowering trees, shrubs, or herbs; however, the caterpillars of the Pandora moth, Coloradia pandora, feed on pine needles. Caterpillars of many species possess stinging hairs that inflict a sharp pain when touched, similar to that received from leaves and stems of nettle (Urtica). The species of Hemileuca are some of the stronger flying silk moths. Saturnia mendocino is rare in the Northwest with less than five records known to us north of the California-Oregon border. Coloradia pandora exhibits a life cycle extending across 2 years and thus shows a pattern of major flight episodes every other year. The species is also a notorious pest in pine forests. Antheraea polyphemus possess a colorful peacock-like eyespot near the center of the hindwing. Hyalophora euryalus flies early in the spring, often seen by mid-March. Ferguson (1971, 1972) and Tuskes et al. (1996) provide detailed illustrations and references to the silk moths of North America.


SPHINGIDAE - the sphinx moths, hawk moths; photographs 236-246.

25 species. Sphinx moths are very strong fliers with their wingbeat producing a sound similar to that of a hummingbird. The strength of flight is evident in the large and firm thorax which houses the flight muscles. The abdomen is also large and firm and is tapered toward the anal end. The forewing of the sphinx moth has the dimensions of a fast flying organism in that the front edge is strongly veined and long, the outer margin angles back to the inner margin giving the wingtip a pointed, tapered outline. This morphology is part of the design of a wing that beats very fast. The adults of most species fly at night and are readily attracted to light. A few species, notably Hemaris diffinis, Proserpinus clarkiae and on occasion Hyles lineata, will be seen flying during the day. Sphinx moths are attracted to flowers that offer nectar and have a long tubular corolla. Many of these flowers are aromatic, white, and flower at night. Caterpillars are known as hornworms. For most species caterpillars feed on the foliage of flowering trees, shrubs, or herbs; however, the caterpillars of Sphinx sequoiae eat junipers (Juniperus) and western red cedar (Thuja plicata). The species of Sphinx are striking in the white, gray, and black markings on the forewings, hindwings, and abdomen. Pachysphinx modesta possess an unusually wide wingspan, exceeding 14 cm in larger specimens. Species of Paonias have colorful eyespots on their hindwing. Hemaris diffinis has extensive areas in the forewing and hindwings that are clear due to a lack of scales. Hodges (1971) provides detailed illustrations and references to the sphinx moths of North America.


THYATIRIDAE - the moths of thyatirids; photographs 247-251.

10 species. The patterns of the lines on the forewings and hindwings of thyatirids are often strongly wavy, curled, or zig-zagged. For instance, the pattern of lines on the wing of Habrosyne scripts is very intricate and unusual among all Lepidoptera. Similarly, the patches and lines on the wings of Euthyatira lorata are unusual and diagnostic for identification of the species. The adults of thyatirids fly at night and are readily attracted to light. Caterpillars feed on the foliage of flowering trees and shrubs.


EPIPLEMIDAE - the moths of epiplemids; not featured with a photograph.

1 species. Callizzia amorata is widely distributed in North America and is common in wet forests in the Pacific West. The adults of epiplemids fly at night and are readily attracted to light. Caterpillars feed on the foliage of honeysuckle (Lonicera).


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