How can you tell the difference between a butterfly and a moth?

    One of the easiest ways to tell the difference between a butterfly and a moth is to look at the antennae. A butterfly’s antennae are club-shaped with a long shaft and a bulb at the end. A moth’s antennae are feathery or saw-edged.

Butterflies and moths have many things in common, mainly scales that cover their bodies and wings. These scales are actually modified hairs. Butterflies and moths belong to the order Lepidoptera (from the Greek lepis meaning scale and pteron meaning wing).

Here are some other ways that help to identify butterflies and moths:

Wings

• Butterflies tend to fold their wings vertically up over their backs. Moths tend to hold their wings in a tent-like fashion that hides the abdomen.
• Butterflies are typically larger and have more colorful patterns on their wings. Moths are typically smaller with drab-colored wings.

Anatomy

Moths have a frenulum, which is a wing-coupling device. Butterflies do not have frenulums. Frenulums join the forewing to the hind wing, so the wings can work in unison during flight.

Behavior

Butterflies are primariy diurnal, flying in the daytime. Moths are generally nocturnal, flying at night. However, there are moths that are diurnal, such as the buck moth and there are butterflies that are crepuscular, that is, flying at dawn and dusk.

Cocoon/Chrysalis

Cocoons and chrysalides are protective coverings for the pupa. The pupa is the intermediate stage between the larva and adult. A moth makes a cocoon, which is wrapped in a silk covering. A butterfly makes a chrysalis, which is hard, smooth and has no silk covering.

As scientists discover and study new species of butterflies and moths, distinctions between the two is becoming blurred. Some moths may fool you into thinking that they are butterflies such as the Urania leilus, a colorful day flying moth from Peru. The Castnioidea moths, found in the neotropics (Indonesia and Australia), exhibit many of the characteristics of butterflies such as brightly colored wings, clubbed antenna and day flying.

More fascinating facts about butterflies and moths.

• There are many more species of moths than butterflies. Butterflies and skippers (hooked-shaped antennae) make up 6 to 11 percent of Lepidoptera order, while moths make up 89-94 percent of the Lepidoptera order.
• It is not true that if you touch a butterfly’s wing and the ‘powder’ rubs off that the butterfly will not be able to fly. The powder is actually tiny scales and a butterfly sheds these ‘scales’ throughout its lifetime.
• Butterflies and moths are holometabolous meaning that they undergo a complete metamorphosis from egg to caterpillar and from chrysalis to adult.
• The largest known butterflies in the world are the birdwings. The Queen Alexandra Birdwing (Ornithoptera alexandrae) from the rain forests of Papua New Guinea has a wingspan of 11 inches. It is the most rare of all butterflies. Click here for a picture of the Queen Alexandria Birdwing. The Goliath birdwing (Ornithoptera goliath), also from the rain forests of Papua New Guinea, is also one of the largest butterflies with an average wingspan of 11 inches.
• The smallest known butterflies are the blues (Lycaenidae), which are found in North American and Africa. They have wingspans from 1/4 - 1/2 inches. Western Pygmy Blue is the smallest. Click here to compare photographs of the smallest and the two largest butterflies.
• The most common butterfly is the Cabbage White found in Europe, North America, Africa, Asia, Australia, New Zealand, Bermuda, and Hawaii.
• The largest known moths are the Atlas moths (Saturniidae) with wingspans as large as 12 inches. Click here to see a photograph of an atlas moth.
• The smallest known moths are from the pygmy moth family (Nepticulidae) with wingspans as small as 3/32 of an inch. Click here to see a photograph of a pygmy moth.

Related Web Sites

Animal Diversity- Lepidoptera - Information about the Lepidoptera order, which includes butterflies, moths, and skippers. Butterfly Conservation Initiative - “The Butterfly Conservation Initiative is dedicated to the conservation of threatened, endangered, and vulnerable North American butterflies and the habitats that sustain them, with a focus on recovery, research, and education." Butterflies and Moths of North America - “This site includes dynamic distribution maps, photographs, species accounts, and species checklists for each county in the U.S. and each state in Mexico.“ Butterflies and Moths of the World - From the Natural History Museum, London “There are currently an estimated 112,000 to 165,000 described species of butterflies and moths (Scoble, 1999) in 24,009 available or objective replacement genus-group names within 131 families. This online catalogue comprises 31,147 entries and includes all published genus-group names.” Migration of the Monarch: Science Reference Guide - This is a guide to Internet resources about butterflies, monarch migration projects, and conservation Web sites. Molecular Expressions: Butterfly Wing Scale Digital Image Gallery Molecular - “… the butterfly wing scale gallery contains digital images taken in brightfield, darkfield, and oblique illumination modes, as well as in reflected light. Each type of illumination results in a different image and, when examined together, they provide a more complete representation of the magnificence and complexity of some of nature’s most splendid creatures.”

Further Reading

Glassberg, Jeffrey. Butterflies through binoculars: the East. New York, Oxford University Press, c1999. 242 p. Glassberg, Jeffrey. Butterflies through binoculars: the West. Oxford, New York, Oxford University Press, 2001. 374 p Mikula, Rick. The family butterfly book: discover the joy of attracting, raising & nurturing butterflies. Pownal, VT, Storey Books, c2000. 166 p. Schappert, Phillip Joseph. A world for butterflies: their lives, behavior and future. Buffalo, NY, Firefly Books, c2005. 320 p. http://www.aworldforbutterflies.com/ Scoble, M.J. Geometrid moths of the world: a catalogue. Collingwood, VIC, CSIRO; Stenstrup, Denmark, Apollo Books, 1999. 1016 p. Urquhart, Fred A. The monarch butterfly: international traveler. Ellison Bay, WI, Wm Caxton, c1998. 232 p.

For more print resources...
Search on "Butterflies," " Lepidoptera," or "Moths" in the Library of Congress Online Catalog.

The Milbert's Tortoiseshell butterfly (Nymphalis milberti) is a harbinger of spring in many northern areas of North America. Photo: NASA Web site.

Folded wings.
Left - Salt marsh moth. Photo: National Parks Service Web site. Bottom: Monarch butterfly. Photo courtesy of Vincent Cavallo.

   
Left - Monarch butterfly caterpillar. From US Fish & Wildlife Web site. Right - Monarch butterfly emerging from the chrysalis. From Fermilab Web site.

Urania leilus - photo courtesy of Mark de Silva, Mississippi Entomological Museum, University of Mississippi.

Castnioidea. Photo: Australian Department of the Environment and Water Resources.

Cecropia moth. Photo: Fermi National Accelerator Laboratory Web site.

Cecropia moth cocoon. Photo: Fermi National Accelerator Laboratory Web site.

Cabbage white butterfly. Photo: U.S. Fish and Wildlife Service Digital Repository Web site.

Anise Swallowtail butterfly. To see a swallowtail chrysalis, click here. To see a swallowtail caterpillar, click here.

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