Boulder Butterfly or Moth? Easy! Check the Frenulum.

Butterflies and moths, both belonging to the order Lepidoptera, are often mistaken for each other due to their similar appearance. However, they exhibit several distinct differences.

One of the primary differences is in their antennae. Butterflies generally have slender antennae with a small ball or club at the end, while moths typically have feathery or filament-like antennae without the club. This distinction is often the easiest way to differentiate between the two.

Owl-eye Butterfly (Caligo atreus) shortly after emerging from its cocoon. Lowland rainforest, La Selva, Caribbean slope, Costa Rica.    photo Lenny Lensworth Frieling

Another difference lies in their behavior and lifestyle. Butterflies are primarily diurnal, meaning they are active during the day. This is when they feed on nectar from flowers, using their long, tubular proboscis. Moths, on the other hand, are mostly nocturnal and are attracted to light at night. Their feeding habits vary; some moths do not feed at all as adults, and those that do may not necessarily feed on nectar.

In terms of life cycle, both undergo complete metamorphosis (egg, larva, pupa, adult), but their pupal stages differ. Butterflies typically form a chrysalis, which is hard and smooth, while moths create a cocoon that is often wrapped in a silken covering.

The resting posture is another notable difference. When at rest, butterflies usually fold their wings vertically over their backs, displaying their vibrant colors. Moths, conversely, rest with their wings spread flat or slightly tented over their bodies.

Traffic Jam In An Uncontrolled Airspace                          photo Lenny Lensworth Frieling

Lastly, the wings of butterflies and moths differ in texture and attachment. Butterfly wings, covered with tiny scales, are generally more colorful and patterned, reflecting their active, diurnal lifestyle. Moth wings tend to be drabber in color, aiding in camouflage, and they have a structure (a frenulum) that joins the forewing and hindwing together, a feature absent in butterflies.

In summary, while butterflies and moths share similarities as part of the Lepidoptera order, they can be distinguished by their antennae, behavior, life cycle stages, resting posture, and wing characteristics.