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

Answer

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.

Hummingbird moth (Hyles lineata) on showy milkweed at Seedskadee National Wildlife Refuge. Tom Koerner, USFWS photographer, 2014. USFWS National Digital Library.

Butterflies and moths have many things in common, including 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).

Moth and three butterlies.? Wenceslaus Hollar, 1646.? Rosenwald Collection, National Gallery of Art.

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 are 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.

Monarch Life Cycle.?Courtney Celley, Tina Shaw and Joanna Gilkeson, USFWS photographers, Shenandoah National Park, 2001.? National Park Service, NP Gallery.

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.
Imperial moth caterpillar,? Moores Creek National Battlefield, 2014.? U.S. National Park Service, NP Gallery.

  • 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. . 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 Karner Blue butterfly.? USGS Multimedia Library.
  • 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.
  • The most common butterfly is the Cabbage White found in Europe, North America, Africa, Asia, Australia, New Zealand, Bermuda, and Hawaii.
Luna moth, Shenandoah National Park, 2015.? One of the largest moths in North America, the luna moth (Actias luna) has a wingspan of up to 4.5 inches (114 mm).? U.S. National Park Service, NP Gallery.

  • The largest known moths are the Atlas moths (Saturniidae) with wingspans as large as 12 inches.
  • The smallest known moths are from the pygmy moth family (Nepticulidae) with wingspans as small as 3/32 of an inch.?
Monarch butterflies (Danaus plexippus), Amistad National Recreation Area, 2015. The monarch is the most familiar North American butterfly and considered an iconic pollinator species. The eastern North American population is notable for its annual autumn southward migration to Mexico which covers thousands of miles.? U.S. National Park Service, NP Gallery.

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