BUTTERFLIES AND MOTHS (Part 2 of 2)   Leave a comment

How the Winter Is Passed

 Moths and butterflies may spend the winter in any stage of their lives. Bag worms hibernate as eggs. The eggs are in cocoon like silken bags about two inches long, hung from the tips of branches. Gypsy moths winter as eggs attached in masses to a piece of wood and covered with scales from the female’s body. Viceroy butterflies winter as caterpillars inside a nest made of a rolled leaf fastened to a twig. The caterpillars of the Baltimore butterfly spin a silken tent on top of their food plant and pass the winter within it. The cat tail moth winters as a caterpillar inside cat tail stalks. The codling caterpillar burrows into an apple, and the corn borer caterpillar spends the winter burrowed into an old cornstalk.

Pupae are well protected from winter cold by silken cocoons or hard, thick cases. The cecropia, promethea, and polyphemus moths winter in their cocoons. The red admiral butterfly hibernates as an adult in hollow logs. The adult mourning cloak butterfly seeks any shelter available.

Although the majority of these insects pass the winter in a resting state, some migrate southward. Great numbers of monarch butterflies are seen flying in the autumn. Some scientists believe that these are dispersal movements or simply a scattering of large populations. There is little evidence of a return flight to the north, except possibly by a few battered individuals. The next year’s population is built up chiefly by monarchs that remained in the northern climate through the winter.

Butterflies and Moths as a Hobby

Monarch butterfly, insect (Danaus plexippus) of the order Lepidoptera, family Danaidae; breeds on milkweeds.

Making a collection of butterflies and moths, carefully mounted and accurately labelled, is a fine hobby. It is interesting to raise these insects from eggs and observe their life history. The abundant monarch butterfly is a good species to start with. Any weedy field with milkweed growing in it is a good place to find eggs and caterpillars. They are to be found on the underside of the leaves.

Do not disturb the eggs or the caterpillar, but pick the plant to which they are attached. Place the plant in a can filled with water to keep the milkweed fresh. Wire such as florists use will hold the weed upright. As the milkweed begins to wither, replace it with a fresh leafy stalk, and let the caterpillar crawl onto it. Monarchs will not eat anything but milkweed, so do not experiment with some other plant.

After five moults the caterpillar reaches a length of about 2 inches and is ready to pupate. Care must be taken to prevent its escape. In nature it will leave the milkweed and crawl to some high support. Strip off the lower leaves of the plant so that they do not form a bridge across the can. The can and the plant also may be covered with a wire screen.

On a rib or stem of the plant or on the screen itself, the caterpillar begins to spin its silk button. Through a magnifying glass the silk can be seen issuing from spinnerets in the head. When the button is completed, the caterpillar turns around, attaches the hooks at the end of its body to the silk, and then gradually releases its hold until it is hanging free, upside down. Several hours elapse. When the long antennae at the head end become limp and shrivelled, the caterpillar is ready to turn into a pupa. Some time before the old skin is ready to split open, the caterpillar begins to swing and jerk. Suddenly at the top of the head the skin opens, and with thrashing movements the insect rolls it up toward the silk button. What is revealed is a beautiful case of jade green studded with golden dots. The pupa case twitches for about two hours, meanwhile shrinking in size. Finally it becomes still. Pupation is completed.

In about two weeks the pupa begins to turn dark. When it is black and transparent, the case opens and the butterfly pulls itself free. For breeding monarchs, the adult must be confined to a cage and provided with a mate. It must have sugared water for nourishment and more milkweed on which the female may lay its eggs. If set free, it can migrate, perhaps thousands of miles, with others of its kind.

Moths as Pests

Adult butterflies and moths do no economic damage. The caterpillars of most butterflies are also harmless. Moth caterpillars, however, cause enormous losses in food plants, fruit, forest and shade trees, clothing, and household goods. Most are better known as “worms” than they are as adult moths.

The clothes moths have infested many households. Two kinds are common. The case-making moth (Tinea pellionella) is so called because the caterpillar spins a shelter case of silk and bits of the material on which it is feeding. The webbing clothes moth (Tineola biselliella), the most abundant and injurious species, spins silky webs as it moves over a piece of material. A third kind, the tapestry moth (Trichophaga tapetezella), is rare in the United States.

The adult moths, or millers, as they are often called, are probably harmless. The clothes moth stays in dark places and flies very little. The adult has imperfect mouth parts It does not feed at all and so does no direct harm to fabric. The female begins to lay eggs, however, before it is a day old, and lays about 100 in the 7 to 14 days of its life.

The soft, white eggs are laid loosely upon the nap of the material on which the larvae are to feed. They are easily dislodged and crushed, so that anything that is regularly brushed or shaken does not become moth infested. In warm weather the eggs hatch in from four to eight days. In colder weather, hatching may take as long as three weeks.

The larvae eat furiously for about 40 days before turning into pupae. The pupa stage lasts eight to ten days in warm weather, and three to four weeks in the winter in a heated building. Eggs, larvae, and pupae die quickly at low temperatures.

Scientific Classification

Scientists divide the order Lepidoptera (scale wings) into two suborders, Rhopalocera, the butterflies, and Heterocera, the moths. The ending -cera means “horn” and refers to the antennae. Rhopalocera means “club-shaped antennae.” Heterocera means “otherwise-shaped antennae.”

The butterflies are divided into the Hesperioidea, or skippers, and the Papilionoidea, or true butterflies. The skippers are so named because of the erratic way they dart about close to the ground. They are seldom more than 1 1/2 inches across the wings. Their antennae are thickened at the ends with a short hooked tip but not knobed.

At rest the fore wings are held vertically while the hind ones are extended horizontally. The body is stout, like the moths. The pupa state is spent in an incomplete cocoon made of leaves fastened together and lined with silk.

Swallowtail butterfly, large butterfly recognized by tail like extension on hind wings; about 20 species in North America n. of Mexico; black swallowtail (Papilio polyxenes), wings black with yellow and orange spots; tiger swallowtail (Papilio glaucus), wings yellow with black bars and yellow spots.

Cabbage butterfly (or white butterfly), insect (Pieris rapae) of the order Lepidoptera, family Pieridae; its larva is a pest on cabbage and cauliflower.

The true butterflies are divided into several families. The Papilionidae include the swallowtails, largest of the American butterflies. The family Pieridae includes the only butterflies injurious to plants. The cabbage butterfly was introduced from Europe in the 19th century. Its larva is a serious pest.

The Nymphalidae, also called brush-footed butterflies, have small, useless, brushlike front feet, usually carried folded against the body. Best known in this family is the monarch butterfly.

In the family Lycaenidae are the small, brightly coloured blues, coppers, and hair streaks The family Riosinidae comprises the metal marks, most of them southern and western species.

The Heterocera, or moths, are also divided into many families. The giant silkworm moths (Saturnidae) include the oriental silkworm and the lovely luna, cecropia, promethea, and polyphemus moths. The large hawk moths, also called sphinx moths (Sphingidae), are often mistaken for hummingbirds. They are about the same size and hover above flowers in the same way. Unlike most moths, they fly about in sunlight.


Posted 2012/03/14 by Stelios in Education

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