SATURNIID MOTH

Eyed silkmoth (Automeris rubrescens) of Central America. also called giant silkworm moth any of the approximately 800 species of the cosmopolitan (principally tropical) insect family Saturniidae (order Lepidoptera). The thick, silken cocoon of saturniid moths is sometimes used for commercial silk. Adults have stout, hairy bodies and broad wings, often vividly coloured and patterned. Most species have a central eyespot marking each wing. The io moth (Automeris io), for example, is characterized by yellow males and red-brown females, and both sexes have a large, dark eyespot on each hindwing. The wingspan of most North American species does not exceed 15 cm (6 inches), but the hercules moth (Coscinoscera hercules) from the tropical forests of Australia has a wing area that reportedly exceeds that of any other insect. This moth, sometimes mistaken for a bird, has broad, dark-brown wings with tails on the hind pair and a wingspan of about 28 cm (11 inches). Adults have reduced, or vestigial, mouthparts, and many never feed. The feathery antennae of males are used to detect the scent of distant females. The large, usually green, larvae feed chiefly on tree foliage. Most species have colourful knots or spines and sometimes irritant barbs. Some spin cocoons; others pupate in the ground. Saturniids have been used in genetic studies of hybridization and variation. The giant cecropia moth (Hyalophora cecropia) has been used in studies of hormonal control of transformation and hibernation. The larvae of the polyphemus moth (Antheraea polyphemus) are green with white lines and are marked by gold knobs; they feed on oak, maple, and birch leaves and pupate in a cocoon in a leaf on the ground. Antheraea species, including A. polyphemus, are sometimes used as a source of commercial silk; e.g., A. assama for muga silk; the Chinese oak silkworm, A. pernyi, for shantung silk; and the Indian moth, A. paphia, for tussah silk. A Southeast Asian silk-producing species is the large atlas moth (Attacus atlas), whose wingspread often exceeds 25 cm (10 inches). The heavily scaled wings of the emperor moth (Saturnia pavonia), which occurs in temperate regions of Europe and Asia, are marked by transparent eyespots, which presumably serve a protective function in frightening predators. Larval forms feed on shrubs. The promethea moth (Callosamia promethea)also called spicebush moth because the larvae feed on spicebush, sassafras, lilac, and related plantsis a common North American saturniid moth. The female moth is maroon in colour, and the male is blackish. The cocoon, formed inside a leaf, is secured to a tree by silk. The beautiful adult luna moth (Actias luna), which has a wingspread of about 10 cm (4 inches), is light green with thin brown borders on each wing and has tail-like projections on the hindwings. It usually occurs in the southern parts of North America. The caterpillar of the cynthia moth (Samia cynthia or walkeri), also known as the ailanthus silk moth, native to Asia and introduced into North America, feeds chiefly on leaves of the ailanthus tree and the castor oil plant. The olive green adult has a distinctive pattern of crescents on its wings. The cocoons, often rolled inside leaves and suspended from a tree, yield a poor-quality silk that is sometimes used commercially. The largest moth native to North America, the cecropia moth (Hyalophora cecropia), attains a wingspread of about 15 cm (6 inches). It is brown with white, red, and gray markings and large, distinctive, crescent-shaped wing spots. The larva grows to 10 cm (4 inches) in length.