This page is about Moths and Butterflies in general. There is more information about the families of Butterflies on their separate pages. Because Moths are hard to identify, we are just giving this one page for all Moth species.
Moth and Butterfly larvae (caterpillars) look fairly similar. They have long soft bodies, sometimes protected with spikes or hairs, and a head with chewing mouthparts. They have six jointed legs and then 1 to 5 (depending on group) pairs of soft unjointed legs called prolegs. Butterfly caterpillars always have 5 pairs of prolegs and are covered with fine hairs. Moth caterpillars may have either 5 pairs or prolegs (often fewer) or hairs, but not both. Most caterpillars are green or brown, and have color patterns that help camouflage them. Some caterpillars are poisonous or have toxic hairs or spines, and they often have bright warning colors to discourage predators from trying to eat them.
Adult Moths and Butterflies all have large wings that are covered with tiny scales. Each scale has a color, and together they give these insects their amazing wing patterns. No other insect groups have this coating of scales on their wings. Butterflies hold their wings up and down over their backs, while moths usually hold them folded down flat. Color patterns vary a lot, but like the caterpillars, they are usually either camouflaged or bright with warning colors.
All Butterflies and nearly all Moth species have special sucking mouthparts that coil up into a little spiral. No other insects have mouthparts that coil up this way. The bodies of these insects are soft, and covered with fine hairs. Butterflies tend to be longer and skinnier, with longer legs, and moths shorter and fatter with thicker hair, but this is not always true.
Butterflies and moths have large eyes and one pair of antennae. Butterfly antennae are thin with a thick section at the tip. Moth antennae are thin all the way to the end, or have lots of side branches so they look like feathers.
Moths and Butterflies are found all around the world. Some species live only in a small area, but many are found all across a continent. There are more than 12,000 species of moths and butterflies known just in the U.S., and probably more than 2,000 species in Michigan. The butterflies are well known, there are 146 species in Michigan, but the moths are not as well-studied. There are many small species that are still unknown to science.
Moths and butterflies usually stay close to the food plants used by their young. However, there are so many kinds of moths, and they eat so many kinds of plants and plant parts, that different species can be found in almost all land habitats. Moth and butterfly caterpillars are usually found on or near their food. The adults are usually nearby, except for a few species that migrate to avoid harsh climates.
Moths and butterflies have complete metamorphosis. Adult females lay eggs, and the young that emerge from these eggs are worm-like larvae called caterpillars. The caterpillars eat and grow fast, and eventually they stop feeding and transform into a pupa, a resting stage that cannot move or feed. Often the caterpillar makes a cocoon to protect it before it transforms. Pupae that do not make a cocoon are called chrysalids. Inside the pupal case the moth or butterfly completes its transformation and emerges as a winged adult.
Adult females mate, and soon after they start to lay hundreds of eggs. They usually lay their eggs on the particular food plant that their young will eat. Sometimes they leave a scent mark on the plant to tell other females that they have already laid eggs there. This way they avoid having too much competition for food between their offspring.
There is no parental care in butterflies or moths.
Most species live only one year. A few live to two or three years, and some only live for a few months. Most species spend the winter as eggs or pupae, a few winter as caterpillars. Only a handful survive the winter as adults, most adults die when the first hard frosts come.
Butterflies are active in the day, and most Moths fly at night. There are some moths that fly in the daylight though. Some Butterfly species, Monarchs and others, migrate south in the early fall to avoid winter cold.
Butterflies use sight more, since they are active in the daylight. Some species have special courtship flights they use to make sure their mate is the right species, and healthy.
Moths use chemical senses more to find each other in the dark. Some male moths can smell a single female from kilometers away.
Most moths and nearly all butterfly caterpillars eat the leaves and flowers of plants. Some moth caterpillars eat fruit, or seeds, and a few eat animal foods like beeswax or fur. A very few species of caterpillars are carnivores, eating aphids or other soft-bodied insects.
Adults mostly drink nectar or sap. They sometimes feed on mud to get minerals, or on animal dung to get protein that they need.
Caterpillars hide and have camouflage, or they collect poisons from the plants they eat and hold them in their bodies. Poisonous caterpillars sometimes stay together in groups, and excrete toxic chemicals on any predators that attack them. If they are attacked they thrash around and try to bite their attacker, or play dead and drop to the ground. Some moth caterpillars have "safety lines" of silk: they drop down and hang on their silk line, then crawl back up after the predator is gone. Others build "tents" or hiding places from their silk, and stay inside when they are not eating.
Adult butterflies rely on camouflage and flight to avoid predators, and some (swallowtails and monarchs especially) are poisonous to predators. Some moths have ears that let them hear the sonar calls of bats. When they hear a bat, they quickly drop to the ground to get away. One family of moths have mostly clear wings and look like wasps, they fly in the daylight and act like stinging insects to fool their predators.
Adults are sometimes valuable pollinators. Caterpillars can be major herbivores, and are food for lots of other animals.
Some species of moths are major agricultural pests. Their caterpillars eat crop plants. Millions and millions of dollars are spent every year trying to protect our crops from these pests. Some get in stored food like grain, or eat wool and fur. A few caterpillars have poisonous hairs or spines that can cause a painful rash if you touch them.
Silk comes from the cocoons of a moth, and many people enjoy the beauty of butterflies and moths.
Some species are endangered, usually because the habitat they need or the food plant they eat is endangered.