| Polyphemus moth | |
|---|---|
| Antheraea polyphemus, adult male | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Lepidoptera |
| Family: | Saturniidae |
| Genus: | Antheraea |
| Species: | A. polyphemus |
| Binomial name | |
| Antheraea polyphemus (Cramer, 1776) |
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| Synonyms | |
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The Polyphemus Moth (Antheraea polyphemus) is a North American member of the family Saturniidae, the giant silk moths.[1] 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.
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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:
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.
Differentiating between sexes of this species is very easy. The most obvious difference is the plumose antennae. 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.
Pests of the moths have become a huge problem. Parasitic insects such as some species of wasps 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. Squirrels 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.
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 eyespots 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.
Brands, S. J.. "Antheraea polyphemus". Systema Naturae 2000. http://www.taxonomicon.net/. Retrieved September 30, 2005.