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Is a Butterfly an Insect? What Science Says

Oregon Swallowtail Butterfly

Classification can be an unusually complicated matter. Species we would consider insects may not necessarily fall into that category. It all depends on their DNA and what species they are related to.

Luckily, butterflies are not one of these confusing cases. Butterflies are considered insects for a few different reasons. Firstly, butterflies have six legs and three main body parts, a requirement of any insect. These body parts include the head, thorax, and abdomen. They also have two antennae and so they are extremely similar to other insects.

Yes, butterflies are easily considered insects.

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The 5 Reasons Why Butterflies are Insects

To qualify as an insect, an animal has to meet a few different requirements. Let’s look at these requirements and how the butterfly adds up.

1. Insects cannot have backbones

Butterflies do not have a backbone, unlike mammals, reptiles, and other species. Instead, they have an exoskeleton. Therefore, their “bones” are on the outside—not on the inside. They are similar to all other invertebrates in this way. (However, not all invertebrates are insects, though they make up a very big portion of them.)

a Pearl Crescent butterfly perched on a yellow and red flower
Image Credit: Joshua J. Cotten, Unsplash

2. Insects cannot have an internal skeleton

We touched on this in the last point but this requirement is technically a bit different from simply lacking a backbone. Insects also have no other bones at all, just like the butterfly. Instead, they have an exoskeleton made out of chitin.

3. They have antennae

All insects have antennae on the top of their head. Usually, it is two antennae. However, it isn’t odd for this to change depending on the species. These antennae function as sense organs.

Peck's Skipper butterfly on a yellow flower
Image By: JamesDeMers, Pixabay

4. Insects have three body segments

Insects also have three different body segments. As we’ve stated, butterflies have these three segments, as well. Therefore, this characteristic helps us put them even more firmly into the insect category.

5. They have six legs

There are some extra requirements regarding these legs, too. Firstly, they must come in pairs, be jointed, and be attached to the thorax section of the animal’s body.

Butterfly legs can get a bit complicated, as well. Several butterfly species appear only to have four legs, which would technically not make them insects. However, these butterflies have a pair of very small, useless legs. These legs aren’t useable, but it is obvious that these species had legs at some point. They just no longer use them for walking.

close up monarch butterfly on a flower
Image By: Erin Minuskin, Unsplash

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What’s the Difference Between a Butterfly and a Moth?

Both butterflies and moths fall into the insect category. However, they both even belong to the same insect group—Lepidoptera. They do differ in a few ways from each other, though. While they may look similar on the outside, they are quite a bit different when you look at the details.

Firstly, butterflies have antennae that are clubbed. In other words, their antennae are straight sticks that end in two larger points. However, moths have fuzzy antennae. This applies to practically all species, with only a few exceptions.

Secondly, butterflies are active during the day. Moths are nocturnal, in contrast. This has led several moth-looking species to be classified as butterflies based on when they are active.

Thirdly, when a butterfly rests, it usually holds its wings upwards and folds together. However, moths typically hold their wings out. They don’t usually fold them upwards like a butterfly. To confuse matters a bit, some species of butterfly rest with their wings out. Also, some butterflies may bask with their wings out.

Sometimes, butterflies are labeled as being more colorful than moths. Of course, this makes sense. It would be hard to see a moth’s pretty colors in the middle of the night. Therefore, they usually aren’t as brightly colored.

But several butterfly species aren’t brightly colored—some of them look like moths. Still, because they are active during the day and exhibit other butterfly traits, they are often considered butterflies.

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Butterflies are considered insects. They meet all of the requirements for being considered an insect—even if you have to look a bit closer for some species.

Insects all have six legs and three different body portions and also have antennae. These characteristics are pretty easy to see, allowing the average person to judge what is an insect and what is not, including butterflies.

Featured Image Credit: Steve Byland, Shutterstock


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