Butterflies & Moths
Butterflies and moths live almost everywhere in the world where plants grow, except Antarctica and the sea. Many have colorful, patterned wings and are among the most beautiful of all insects. There are about 18,000 species of butterfly but many more months. At least 170,000 species of moth are known and experts think there may be thousands more yet to be discovered. The biggest butterflies and moths are the birdwing butterflies of New Guinea and giant silk moths, both of which can grow up to 30 centimeters from wingtip to wingtip. The smallest are some species of moth that measure only 16 millimeters.
DIFFERENCES BETWEEN BUTTERFLIES AND MOTHS
Generally, moths are dull grey or brown creatures that fly at night, while butterflies are bright and beautiful and come out in the daytime. But this is not always the case—there are colorful, patterned moths and those that fly in the daytime, and there are also dull brown butterflies. One important difference between the two is in the feelers on their heads (antennae). Butterflies have little club-like tips on their antennae, but moths do not. Also, when at rest butterflies hold their wings upright or spread to each side. Moths usually fold their wings flat over their backs. Otherwise, the structure of the body is the same.
A butterfly, like all insects, has three parts to its body—a head, thorax and abdomen—and three pairs of legs. It also has two pairs of large wings, which are attached to the thorax, the middle part of the body. The wings are covered with tiny scales that overlap like tiles on a roof. These scales are often very colorful, even shimmering in some species. On the head there are two antennae that are very sensitive to smell, helping the insect to find food. Many moths have very large feathery antennae and a particularly good sense of smell. When ready to mate, a male moth can pick up the smell of a female from several kilometers away.
A butterfly’s mouth is like a long tube, which it keeps curled up when not feeding. To feed, the butterfly uncurls the tube, called a proboscis, and uses it like a drinking straw to suck up liquid food such as flower nectar, rotting fruit or tree sap. Many butterflies and moths are important pollinators. As they fly from flower to flower feeding on nectar, they take pollen grains from one to another, helping the plants to reproduce. Some butterflies also drink from muddy pools or suck the fluid from dead animals. A few months have tiny jaws instead of a proboscis. They use these for chewing pollen grains.
FROM EGG TO PUPA
A butterfly’s life is divided into several stages. Eggs are usually laid on leaves and each egg hatches into a tiny larva called a caterpillar. It has three pairs of legs and may also have several pairs of little stumpy structures called prolegs behind the real ones. These are tipped with tiny claws and are used for holding on as the caterpillar crawls on plants.
As soon it hatches the caterpillar starts to munch the leaves, buds, and flowers around it. It eats almost all the time and grows so fast that it has to shed its skin several times as it gets larger. When it is fully grown the caterpillar stops eating and gets ready for the next stage in its life. It attaches itself to a twig or other support by a little pad of silk and then sheds its skin to reveal a hard case or pupa underneath. Some moths also spin a cocoon of silk around themselves. Inside this pupa or chrysalis, the body of the caterpillar breaks down and is remade into an adult butterfly. When the change is complete, the pupal case splits and the butterfly crawls out, ready to fly away and find a mate. This transformation or change from caterpillar to butterfly is called metamorphosis.
Lots of birds, lizards, bats and other animals eat caterpillars. To protect themselves, some caterpillars have markings that look like large eyes on their bodies. These may fool predators into thinking the caterpillar is a much larger animal than it is, and convince them that it is not a good idea to attack. Other caterpillars taste bad and some have tiny stinging hairs on their bodies. Poisonous and stinging caterpillars are often very brightly colored as a warning to other creatures—a way of saying “stay away from me or else!”
Butterflies and moths, too, are food for many creatures. Many moths depend on camouflage to keep themselves safe. They have wings that look just like bark or moss so that when they lie still on a tree trunk they are almost impossible to see. Some butterflies such as swallowtails have tail-like shapes on their wings to distract a predator. If a bird pecks at these rather than at the butterfly’s head, the insect is more likely to escape. Others, like caterpillars, are poisonous and have bright markings. After one taste birds soon learn to stay well away.