Life Cycle of Butteflies, Moths and Caterpillars

Life Cycle of Butteflies, Moths and Caterpillars
Page content

The Family Tree

Moths and butterflies are part of a large order or group of insects called the Lepidoptera. This circle of family friends includes more than 20,000 kinds of butterflies and they circle the earth everywhere except Antarctica. If you want to see the most variety, you would have to travel to various tropical rain forests where they range from the smallest—the pygmy blue, which is smaller than a thumbtack—to the biggest butterfly –the rare Queen Alexandra, with a wingspan of more than 11 inches across.

Close-up and Personal

Since butterflies hang out mostly during the daylight hours, they are easy to examine and catch, provided you are good with a net. They are quite delicate however, (their wings can rub off like dust), so make sure not the damage the scales of their wings as you handle them.

Their bodies are divided into three parts, similar to other insects. There is the head, the thorax and the abdomen. A butterfly head has a mouth, eyes and feelers called antennae (pronounced: an-TEN-ee), which smell for food. The main middle section of the thorax contains the muscles that power the wings and legs, while the abdomen is where the butterfly digests its food.

With no bones, their bodies bear exoskeletons, hard-cased shells often generously sprinkled with hair. They have long tongues called proboscises, but the beautiful, big flat wings attract us most.

Their mouth is quite funny because essentially it looks like a coiled-up straw. It makes sense when you observe that this tube uncoils to sip up the sweet nectar found in blossoming flower blooms.

Parts by the Number

A butterfly has six legs and four delicate wings. In addition, one of the most interesting and useful parts is the taste sensors at the ends of their legs; they can taste with their feet! They can also hear with their legs, because these special appendages can pick up vibrations out of the air and turn them into sound.

Their wings are covered with scales that are built up like a mosaic and determines their colors and patterns. Light reflects off the scales and separates into iridescent, shimmering color. The scales have helped to name this species because lepis means “scales” in Greek, and the pteron means “wings.”

Their abdomen houses the heart and other organs but there are air holes there for breathing. Compound eyes may seem freaky to us because there are hundreds or even thousands of eyelets. Each eyelet projects a different view and that gives the butterfly all-around vision with which to spot the enemy even though they are quite nearsighted.

Feed Me

Butterflies suck up liquids through their long hollow tongues, but all species do not always eat flower nectar.

For instance, woodland butterflies like to feast on rotting fruit or partake in the sap that oozes from tree wounds. Speckled wood butterflies prefer to dine on “honeydew”—not the fruit, but sweet liquid leached by tiny plant-eating insects called aphids. Some male butterflies like to pick up the dissolved salts that occur in mud puddles. Other butterflies even sip animal dung for the nutrients and vitamins inside.

The tropical longwings pick up pollen in addition to nectar. It sticks on their proboscis and hairy legs and they moisten it with saliva in order to swallow it. Spreading pollen is extremely important in a relationship referred to as mutualism. The flower depends on the butterfly to pollinate or cross-pollinate it. According to studies at the University of Idaho, pollination is a precondition for fertilization: it is the fusion of nuclei from the pollen grain with nuclei in the ovule and that allows the flower to develop seeds.

Reproduction or Metamorphosis

Butterfly Metamorphosis

The typical life cycle of a butterfly such as the gorgeous monarch begins inside a tiny white egg. The female deposits the egg to a milkweed plant leaf. After about four days, a larva hatches as it chomps through its eggshell and crawls out (what hatches is also called a caterpillar). This caterpillar can eat several times its own body weight every day. What better way to start the feasting then with the egg shell and the milkweed leaf it is sitting on, which also makes them stinky and unappealing to taste to many predators? The caterpillar molts, or sheds its skin, about five times.

When it reaches about two inches in length, the caterpillar creeps out to the stem of a leaf. It affixes itself to the stem and literally stands on its head. Soon the stripes of the caterpillar skin turn greenish. Finally the skin splits, falls off and what is left is the chrysalis or pupa. The pupa almost looks like a fuzzy blanket that wraps around the growing life form inside.

The chrysalis goes through some changes itself—starting out long and soft, then shrinking and hardening. It also morphs into a light green color with gold dots. 10 days to two weeks later, the casing splits and a crumpled monarch immerges.

Still hanging upside-down, fluid is pumped into the wings and they get bigger while the abdomen gets smaller. The metamorphosis is complete. The butterfly dries in the sun, its wings harden and it eventually flies away. The monarch can live up to eight months.


In the fall, monarch butterflies travel south. Their migration can take them as far as 2,500 miles (4,023 km) away.

Traveling in groups, their orange wings flap until they reach Southern California or Mexico, where thousands gather in trees. In spring, they mate—a goal for reproduction—and it all begins again.


Male butterflies mate several times but the females mate just once. Once she mates, the female will give off a scent to deter other males.

Swallowtail caterpillars emit a foul smell when threatened.

Monarch butterflies have a circadian clock in the brain but also have a second clock based in their antennas, according to a new study by Dr. Steven M. Reppert, chairman of neurobiology at the University of Massachusetts Medical School.

It’s a great hobby to capture caterpillars and witness their transformation. There are many things to be learned from this interesting creature. You may even want to start a butterfly garden.


  • Merritt, Robin. The Life Cycle of a Butterfly. Mankato, MN: The Child’s World, 2012. Book.
  • Animal Migrations
  • Farndon, John. In Touch with Nature: Butterflies and Moths, Farmington Hills, MI: The Gale Group, 2004. Book.
  • Butterfly Gardening
  • Gibbons, Gail. Monarch Butterfly. New York: Holiday House, 1989. Book.