Eastern Giant Silkworm Moths

     Eight kinds of giant silkworm moths, including luna, polyphemus, promethea, emperial, regal, and rosy maple moths of deciduous forests and cecropia and I O moths of more open habitats, including suburban areas, inhabit the eastern United States.  As a group, they are the largest moths in America, with most species having wing spans of four to five inches across.  They have furry bodies and feathery antennae.  All species, except regals and rosy maples, blend into their surroundings, which protects them from predation.  These moths are short-lived, however, and don't eat anything.  They live off what they ate when they were caterpillars.  Their only purpose in life is to mate and lay eggs before they die.  They are active mostly at night and many of them gather around outdoor lights, where we are most likely to see them at night.  I have seen at least a few lunas fluttering around the bright lights of gas stations at night.
     Although most of these moths are basically brown, they can be identified by the colors and patterns on their wings.  Lunas, for example, have pale-green wings, the only large moth to have such color.  I've seen them at dusk in woods where they looked like tiny ghosts fluttering among the tree trunks.  Regals have gray wings with orange striping.  Rosy maples are a beautiful shade of pink and gray.  And imperials are yellow and gray on their wings.      
     Some of these moth species, including polyphemus, promethea, cecropia, luna and IO, have "eye" spots on their wings as a form of mimicry.  Those eye spots make the moths that bear them look like something more fierce than they are, which would intimidate some predators.  I O moths, for example have large "eyes" on the upper surfaces of their two hind wings.  When the two fore wings are folded over the hind wings, the moth looks brown and vulnerable.  But when alarmed by a would-be predator, the IO suddenly opens its front wings to reveal the hind wings, which resemble the face of an owl, probably startling away the threatening animal.     
     The caterpillars of these moths are three to five inches long, depending upon the species, and well protected against predation.  Most of them are largely green to blend into the green tree leaves they eat.  Only the larvae of the regal moth are not green.  But the caterpillars of regal moths, called hickory horned devils because of their fierce looks, are protected by four one-inch-tall, orange spines in front and short, dark tubercules along the body, making them look like a nasty mouthful. 
     Other types of caterpillars also have spines that protect them, including cecropia, I O, rosy maple and promethea.  Those spines make each larvae look unappetizing to birds and other kinds of
predators.
     While some species of moth caterpillars consume a variety of tree leaves, others have special foods.  Regal caterpillars, for example,only eat black walnut, hickory and staghorn sumac leaves.  Promethea larvae only ingest spicebush and sassafras foliage.  Rosy maple larvae consume the leaves of red maples and silver maples.    
     Most of these moth species overwinter as pupae, mostly among dead,fallen leaves on forest floors where they are somewhat protected from cold.  But there they could be found and eaten by skunks, shrews and other animals.  If they are not eaten in winter, they emerge from their cocoons in the warmth of summer and carry out their reproductive duties before dying. 
     Although we don't see these moths much because most of them are forest creatures and all of them travel during the dark of night, they are a treasure when experienced.  And even if we don't see them, it's still nice to know they are out there in the woods, carrying out their life cycles.