Lepidoptera is the order that includes butterflies, moths, and skippers. This order of over 180,000 species belongs to class insecta, in phylum arthropoda. Lepidoptera is made up of around 160,000 species of moths, 17,000 species of butterflies, and 3,500 species of skippers. These insects evolved around 300 million years ago alongside an increase in flowering plants. Being pollinators, they helped disperse pollen which led to diversification of many flowering plant species. Butterflies, moths, and skippers are found on every continent except Antarctica and have a diverse variety of colors, wing shapes, and patterns. This order has a wide range of sizes, with wingspans of 0.05 inches for the Stigmella maya moth to 12 inches for the Atlas Moth.
Left: Rosy Maple Moth by Ken Childs. Right: Fatal Metalmark butterfly by Katja Schulz
There have been categories set to show differences between the three groups but many species among them break these “rules.” Among the stereotypical misconceptions, it is believed that they have set times of day that they are active, set color tones, set body size. We have been led to believe that all moths are dull and nocturnal while butterflies are colorful and diurnal. These associations are often proven true, but there are many instances where the shared similarities make it hard to identify a species in nature. Examples like the Rosy Maple Moth and the Fatal Metalmark butterfly both defy their usual color schemes.
Many of the main differences in the order are between butterflies and moths. Their behaviors and physical appearances are the best example of these differences. The wing structure of butterflies has the wings resting upwards, in the closed position. Moths have a row of bristles, called a frenulum, that connects the hindwing and forewing. This addition makes moths rest their wings open, along their body. This is a trait found in most moths, but not in butterflies or skippers.
Another of the main differences between the three groups are their antennae. Butterflies have long straight antennae with a club shape on the end. Skippers have similar long straight antennae but instead of a club shape, the ends of their antennae are hooked. Moths differ the most, they have straight pointed antennae or comb like antennae. The shorter comb antennae are only found in some species of male moths, this helps them detect pheromones put out by females in the area.
Moths tend to have a larger body compared to the butterflies slender abdomen. This occurs because moths have larger and thicker scale size, which also gives them a fuzzier appearance. Skipper wings are smaller in relation to their body size, and are more angular than moth and butterfly wings.
Left: Giant Silkmoth cocoon by Kim Smith Films. Right: Monarch Butterfly pupa by MBL
During the life cycle of the Lepidoptera order, caterpillars transform into winged insects. For butterflies, this happens in a pupa. The pupa is a hard protective covering grown by the butterflies that will hang off branches until they are completed with their metamorphosis. Moths also have pupas, but they have an extra outer layer of protection called a cocoon. These silk cocoons are spun by the moths before they begin their metamorphosis.
Generally, butterflies pollinate and fly during the day, as they are diurnal, and moths are more active at night, being nocturnal. However this is not true in all instances, and many moth species are active during the day. Of the daytime moth species, most are brightly colored. The eyes of the groups also differ slightly. Moths and Skippers both have superposition eyes, while butterflies have apposition eyes. Superposition eyes are found in nocturnal insects and some crustaceans in dimly lit environments. These eyes will produce a single erect image against the retina. Apposition eyes have many lenses that produce many small inverted images that are composited together. Apposition eyes are found in diurnal insects like butterflies and bees.
Butterflies and Moths are the two main groups, but there is some debate whether skippers are in the same category as butterflies. Since there are many defining characteristics in skippers, some experts consider them their own group. Skippers are visually more similar to moths and share their eye structure, but are considered butterflies because of their lack of frenulum and use of pupas instead of cocoons. In previous taxonomy Skippers had their own super family called hesperioidea, until 2014 when they were reclassified as a family in the butterfly group. They have shorter, wider bodies and are generally hairier than butterflies. They have much larger eyes in comparison to the other two Lepidoptera groups. Skippers are also the fastest group of the three. They can reach speeds of up to 37 miles per hour and have some of the fastest reflexes in nature. Skippers are a diurnal species, like butterflies and some moths.
The Lepidoptera order is a diverse collection of fascinating flying insects. 276 of those species are found here, in Orange County. There are a few differences that set them apart, but they are more similar than you might have previously thought. Check out our other blog articles to find out how you can help protect our many Lepidoptera species!
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