There are a few simple ways to distinguish moths from butterflies by looking at their physical characteristics and behavior.
There are about 524 species of butterflies in the eastern half of North America alone, and about 11,000 species of moths across the entire U.S. Because of the sheer number of species, with some moths as colorful as butterflies, and some butterflies appearing moth-like, it can often be difficult to identify which is which.
Here are five ways moths and butterflies are different:
- The time of day they are active.
- The characteristics of their wings and bodies.
- The type of antennae they have.
- The way they feed.
- How they develop from the larval stage.
Moths and Butterflies are Active at Different Times
Generally speaking, it has always been understood that butterflies are active during the day, and moths are active at night. But there are exceptions. Some moths are day fliers, and some butterflies are active in the evening.
An example of a moth seen in daytime is the Hummingbird Clearwing (Hemaris thysbe), a sphinx moth which is often mistaken for a hummingbird because of its size and preference for feeding on nectar from flowers that hummingbirds also visit.
Butterflies active at or after dusk include the 21 neotropical Owl Butterfly species in the genus Caligo. While most likely found in the wild in cloud forests of Central America, some butterfly sanctuaries in North America, such as the Victoria Butterfly Gardens in British Columbia, offer them for viewing.
These butterflies have feathery underwings, wing spots that resembles false eyes, and they feed on rotting fruit on the forest floor. Despite their nocturnal tendency, they will fly by day in darker parts of the forest or when the weather is dreary.
Moths Hold Their Wings Differently Than Butterflies
When moths land, they keep their wings stretched out flat, or fold them up against their backs. Butterflies are seen at rest with their wings outstretched, or held together vertically.
While both moths and butterflies have minute scales on their wings that give them their special colors and repel water, moths have a thicker coating of scales that make them appear more “furry” and keeps them warmer at night when they are active.
Additionally, moths are generally more plump to conserve body heat, while butterfly bodies are more slender.
Features of Moth and Butterfly Antennae
Moths have antennae that usually have a great deal of surface area, so they are configured with feathery filaments, appearing brush-like or branched.
Some moths do have simple, straight filaments but in both cases the antennae lack the clubbed or knobbed ends usually found on butterfly antennae. The antennae contain cells and sense organs that help these insects with balance, motion and smell.
How Moths and Butterflies Feed
A butterfly has a feeding mechanism that some moths don’t have. The feeding mechanism, called a proboscis, is long or short and coiled under the head. It is used to gather moisture from mud, nectar from flowers, or fluid from fruits.
A long proboscis indicates a species that feeds on nectar, and a short proboscis is more likely on sap- or fruit-feeding species.
The reason why some adult moths don’t have a proboscis, unlike butterflies, is because they don’t eat in the adult stage; they have fed all they need to in the larval stage.
How Moths and Butterflies Develop From Larvae
One basic difference in the way adult moths and butterflies form is how they develop from the larval stage. Moths emerge from a cocoon of silk that has been spun around the pupa—the form between the larval and adult stages of transformation.
A butterfly chrysalis is the actual pupa, which has emerged from the split skin of the caterpillar, and is used to house the developing adult butterfly. When the butterfly emerges from the chrysalis, it is actually splitting open the skin of the (former) pupa.
Butterflies and moths are amazing insects. Anyone who has seen a Luna Moth (Actias luna) would agree that moths can be as captivating as the most beautiful butterfly. A visit to a butterfly sanctuary or excursion outdoors, with field guide in hand, offers an open door to new discoveries about these delicate insects.