Is it a moth or a butterfly?
It sounds like a simple question, and there are a few simple ways to answer it: If it flies during the day, it’s a butterfly; if it flies at night, it’s a moth.
However, there are diurnal moths — those that fly during the day, and there are crepuscular butterflies that fly during dawn or dusk.
You could also answer the question, if it has bright colored wings, it’s a butterfly, but if it has dull colors it’s a moth.
But yet again, that doesn’t always apply. The Madagascan sunset moth has crazy bright colors, and the common sootywing butterfly is pretty drab.
It turns out there are plenty of hard and fast rules that quickly become loose when looking at the thousands of species of butterflies and moths in the world.
In the order of Lepidoptera, which contains both butterflies and moths, about 89-94 percent of the species are moths while 6-11 percent are butterflies. All of these species have wings with scales that are shed over their lifetimes. They all have three body parts. The head has two compound eyes, two antenna and a proboscis that extends to suck up liquid like water or nectar. The thorax and abdomen house the two pairs of wings and three pairs of legs.
Plus, all moths and butterflies go through complete metamorphosis, from egg to larva (caterpillar) to pupa (chrysalis or cocoon) to adult.
There are some simple ways to tell apart most moths and butterflies.
Frenulum: Moths usually have a frenulum, which is a wing-coupling device that joins together the forewing and hindwing. Butterfly wings are separate except for the Regent Skipper in Australia which is the only known butterfly to have a frenulum. Some moths don’t have a frenulum.
Antenna: Butterfly antenna are club-shaped with a long shaft and a bulb at the end. Moth antenna are typically feather or saw-edged. Some moths do have club-shaped antenna, but no butterflies have feathery antenna.
Caterpillars: Both moths and butterflies are caterpillars in the larval stage, and many moth caterpillars can be described as fuzzy, although not all. No butterfly caterpillars are considered fuzzy.
Pupa: In the pupa stage, moths create a cocoon, which is wrapped in a silk covering. Butterflies create a chrysalis, which is hard, smooth and is not silky. Not all moths create a cocoon though. The tomato hornworm, for example, creates a pupation chamber in the ground instead.
Wings: Moths usually land with wings spread, whereas butterflies tend to land with their wings folded back.
Body shape: Moth bodies are most often shorter, fatter and have thicker hair than butterfly bodies, which are usually longer, skinnier and have longer legs.
The fact that each species is unique makes identification a challenge, but it also proves how incredibly awesome the natural world is.