Antheraea polyphemus
Encyclopedia
The Polyphemus Moth is a North America
n member of the family Saturniidae
, the giant silk moths. It is a tan colored moth, with an average wingspan of 15 cm (6 inches). The most notable feature of the moth is its large, purplish eyespots
on its two hindwings. The eye spots are where it gets its name – from the Greek myth of the Cyclops Polyphemus
. The caterpillar of the Polyphemus Moth can eat 86,000 times its weight at emergence in a little less than two months. It is widespread throughout much of North America, from southern Canada
to parts of Mexico
.
When the eggs hatch small yellow caterpillars emerge. As the caterpillars age, they molt 5 times (the 5th being into a pupa). Each instar
is slightly different, but on their fifth and final instar they become a bright green color with silver spots on their side. They feed heavily on their host plant and can grow up to 3—4 inches long. They then spin cocoons of brown silk
, usually wrapped in leaves of the host plant.
There are generally two broods throughout the United States, one that hatches in early spring and one that hatches in late summer. The moths eclose
and then must pump their wings with fluid (hemolymph
) to extend them. The females emit pheromones, which the male can detect through its large, plumose antennae
. Males can fly for miles in order to reach a female. After the moths mate, the female spends the majority of the remainder of her life laying eggs, while the male may mate several more times. Adults of this family of moths have vestigial mouths, meaning their mouth parts have been reduced. Because of this, they do not eat and only live as adults for less than one week.
In captivity, this moth is much more difficult to breed than other American Saturnids such as the cecropia, promethea or luna. Kept in a cage, the male and female tend to ignore each other, unless a food plant (particularly oak leaves) are present.
. Males will have very bushy antennae while females will have moderately less bushy antennae. The male's bushy antennae are used to detect pheromones released by unmated females. Another difference is that the females will be slightly larger in the abdomen due to carrying eggs. There is a surprising amount of variation within this species. Color patterns can range from a reddish-cinnamon to a dark brown but are almost always a shade of brown.
s such as some species of wasp
s and flies
lay their eggs in or on the young caterpillars. The eggs then hatch into larvae which consume the insides of the caterpillars. Once the caterpillars pupate, the larvae themselves pupate, killing the Polyphemus pupa. Squirrel
s have also been known to consume the pupae of Polyphemus Moths, decreasing the population greatly. Pruning of trees and leaving outdoor lights on at night can also be detrimental to the Polyphemus Moths.
s on its hindwings, which give the Polyphemus its name (from the Cyclops
Polyphemus in Greek mythology). Eyespots are also startle patterns, a subform of distraction patterns, used for camouflage
via deceptive and blending coloration. Most startle patterns are brightly colored areas on the outer body of already camouflaged animals. (Another example of the use of startle patterns is the gray tree frog
, with its bright yellow leggings. When it leaps, a flash of bright yellow appears on its hindlegs, usually startling the predator away from its prey.) It is believed that distraction patterns are a form of mimicry, meant to misdirect predators by markings on the moths' wings
.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n member of the family Saturniidae
Saturniidae
The Saturniidae, commonly known as saturniids, are among the largest and most spectacular of the moths. They form a family of Lepidoptera, with an estimated 1,300 to 1,500 described species worldwide...
, the giant silk moths. It is a tan colored moth, with an average wingspan of 15 cm (6 inches). The most notable feature of the moth is its large, purplish eyespots
Eyespot (mimicry)
An eyespot is an eye-like marking. They are found on butterflies, reptiles, birds and fish. In members of the Felidae family , the white circular markings on the backs of the ears are termed ocelli, and they are functionally similar to eyespots in other animals.Eyespots may be a form of...
on its two hindwings. The eye spots are where it gets its name – from the Greek myth of the Cyclops Polyphemus
Polyphemus
Polyphemus is the gigantic one-eyed son of Poseidon and Thoosa in Greek mythology, one of the Cyclopes. His name means "much spoken of" or "famous". Polyphemus plays a pivotal role in Homer's Odyssey.-In Homer's Odyssey:...
. The caterpillar of the Polyphemus Moth can eat 86,000 times its weight at emergence in a little less than two months. It is widespread throughout much of North America, from southern Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
to parts of Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
.
Life cycle
The life cycle of the moth is much like that of any other saturniidae species. It lays flat, light brown eggs on the leaves of a number of host plants, including:- Betula, (birch)
- Salix, (willow)
- Quercus, (oak)
- Acer, (maple)
- Carya, (hickory)
- FagusBeechBeech is a genus of ten species of deciduous trees in the family Fagaceae, native to temperate Europe, Asia and North America.-Habit:...
, (beech) - Gleditsia triacanthos, (honey locust)
- Juglans, (walnut)
- Pyrus, (pear and quince)
- PrunusPrunusPrunus is a genus of trees and shrubs, which includes the plums, cherries, peaches, apricots and almonds. There are around 430 species spread throughout the northern temperate regions of the globe. Many members of the genus are widely cultivated for fruit and ornament.-Botany:Members of the genus...
, (plum, peach, apricot, cherry, etc.) - SassafrasSassafrasSassafras is a genus of three extant and one extinct species of deciduous trees in the family Lauraceae, native to eastern North America and eastern Asia.-Overview:...
- CitrusCitrusCitrus is a common term and genus of flowering plants in the rue family, Rutaceae. Citrus is believed to have originated in the part of Southeast Asia bordered by Northeastern India, Myanmar and the Yunnan province of China...
, (orange, grapefruits, lemons, limes, etc.) - Ulmus americana, (American elm)
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
is slightly different, but on their fifth and final instar they become a bright green color with silver spots on their side. They feed heavily on their host plant and can grow up to 3—4 inches long. They then spin cocoons of brown silk
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...
, usually wrapped in leaves of the host plant.
There are generally two broods throughout the United States, one that hatches in early spring and one that hatches in late summer. The moths eclose
Eclose
Eclose is a commune in the Isère department in south-eastern France....
and then must pump their wings with fluid (hemolymph
Hemolymph
Hemolymph, or haemolymph, is a fluid in the circulatory system of some arthropods and is analogous to the fluids and cells making up both blood and interstitial fluid in vertebrates such as birds and mammals...
) to extend them. The females emit pheromones, which the male can detect through its large, plumose antennae
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
. Males can fly for miles in order to reach a female. After the moths mate, the female spends the majority of the remainder of her life laying eggs, while the male may mate several more times. Adults of this family of moths have vestigial mouths, meaning their mouth parts have been reduced. Because of this, they do not eat and only live as adults for less than one week.
In captivity, this moth is much more difficult to breed than other American Saturnids such as the cecropia, promethea or luna. Kept in a cage, the male and female tend to ignore each other, unless a food plant (particularly oak leaves) are present.
Sexual dimorphism
Differentiating between sexes of this species is very easy. The most obvious difference is the plumose antennaeAntenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
. Males will have very bushy antennae while females will have moderately less bushy antennae. The male's bushy antennae are used to detect pheromones released by unmated females. Another difference is that the females will be slightly larger in the abdomen due to carrying eggs. There is a surprising amount of variation within this species. Color patterns can range from a reddish-cinnamon to a dark brown but are almost always a shade of brown.
Threats
Pests of the moths have become a huge problem. Parasitic insectInsect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s such as some species of wasp
Wasp
The term wasp is typically defined as any insect of the order Hymenoptera and suborder Apocrita that is neither a bee nor an ant. Almost every pest insect species has at least one wasp species that preys upon it or parasitizes it, making wasps critically important in natural control of their...
s and flies
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
lay their eggs in or on the young caterpillars. The eggs then hatch into larvae which consume the insides of the caterpillars. Once the caterpillars pupate, the larvae themselves pupate, killing the Polyphemus pupa. Squirrel
Squirrel
Squirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots , flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia...
s have also been known to consume the pupae of Polyphemus Moths, decreasing the population greatly. Pruning of trees and leaving outdoor lights on at night can also be detrimental to the Polyphemus Moths.
Response to threats
The Polyphemus Moth uses defence mechanisms to protect itself from predators. One of its most distinctive mechanisms is a distraction pattern that serves to confuse, or simply distract, predators. This involves the large eyespotEyespot (mimicry)
An eyespot is an eye-like marking. They are found on butterflies, reptiles, birds and fish. In members of the Felidae family , the white circular markings on the backs of the ears are termed ocelli, and they are functionally similar to eyespots in other animals.Eyespots may be a form of...
s on its hindwings, which give the Polyphemus its name (from the Cyclops
Cyclops
A cyclops , in Greek mythology and later Roman mythology, was a member of a primordial race of giants, each with a single eye in the middle of his forehead...
Polyphemus in Greek mythology). Eyespots are also startle patterns, a subform of distraction patterns, used for camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...
via deceptive and blending coloration. Most startle patterns are brightly colored areas on the outer body of already camouflaged animals. (Another example of the use of startle patterns is the gray tree frog
Tree frog
Hylidae is a wide-ranging family of frogs commonly referred to as "tree frogs and their allies". However, the hylids include a diversity of frog species, many of which do not live in trees, but are terrestrial or semi-aquatic.-Characteristics:...
, with its bright yellow leggings. When it leaps, a flash of bright yellow appears on its hindlegs, usually startling the predator away from its prey.) It is believed that distraction patterns are a form of mimicry, meant to misdirect predators by markings on the moths' wings
Insect wing
Insects are the only group of invertebrates known to have evolved flight. Insects possess some remarkable flight characteristics and abilities, still far superior to attempts by humans to replicate their capabilities. Even our understanding of the aerodynamics of flexible, flapping wings and how...
.