Do Butterflies Have Bones: Yes, But..

Yes, butterflies have bones, but it’s a little bit different than a human skeleton. The bones are on the outside of a butterfly's body which protects it from the elements. The size and shape of its skeletal system are different between species of butterflies. Different species have a thicker frame, while others are thin and petite.

The Anatomy of a Butterfly

To understand the hard exoskeleton of a butterfly, let’s take a look at a butterfly’s general anatomy.

Butterflies are arthropods, which means they have segmented body parts covered in a hard shell. A butterfly is divided into three parts, a head, thorax, and abdomen. What makes up these three body parts, and how do they work together?

• Head. The head of a butterfly is covered in a hard exoskeleton to protect it. The head is composed of antennae, compound eyes, and a proboscis. The proboscis is a tubular mouthpart used to suck the nectar from flowers.
• Thorax. The thorax is home to the forewings, hindwings, and legs. Most of the muscles of a butterfly are found on the thorax to help propel the wings so the butterfly can take flight and move its legs.
• Abdomen. The abdomen houses important internal organs like the digestive tract, spiracles, dorsal aorta, and breathing tubes. The exoskeleton on the abdomen is much thicker than the rest of its body to protect its delicate organs.

Are There Bones in a Butterfly’s Wings?

While it may look like a highway of bones running through a butterfly’s wings (like in the Monarch butterfly), those are actually veins. But these aren’t your normal veins because they don’t pump blood.

During the pupa stage, a butterfly emerges from its chrysalis or cocoon and pumps air through the veins in its wing to help it emerge.

Do butterflies have exoskeletons?

Yes, butterflies have exoskeletons. Unlike humans, butterfly’s bones are on the outside of their bodies. Exoskeletons are made from a material called chitin.

Chitin is composed of polysaccharides, which are simply glucose molecules found in food sources. So, basically, a butterfly is made of sugar! It’s very butterfly-like.

How Many Bones Does a Butterfly Have?

Simply put, a butterfly has one giant bone. While the term exoskeleton means ‘external skeleton’, it’s very different from an internal skeleton found in vertebrates. There isn’t a series of intricate bones pieced together to create an exoskeleton.

So, it’s not possible to count the number of bones on a butterfly or other invertebrates like dragonflies, grasshoppers, and octopuses.

Think of an exoskeleton like the coating on a caramel apple. It coats the apple in one hard shell. The same can be said for the exoskeleton of a butterfly. Hardened chitin coats the entirety of the butterfly to protect the entire frame.

What about caterpillars?

Caterpillars also have an exoskeleton like a butterfly, but it works a little differently. What makes a caterpillar’s exoskeleton different than a butterfly’s is that larvae molt, while butterflies do not. As a caterpillar grows, it needs to shed its hard exoskeleton to accommodate its larger body throughout its life cycle.

A caterpillar will molt (or shed its exoskeleton) up to five times before entering the pupae stage. If you ever come across a caterpillar that isn’t eating or moving – let it be. It’s likely in the process of molting.

What are Butterfly Wings made of?

Butterfly wings are made from chitin but in a much thinner layer. If the layer was any thicker, it would be difficult for the butterfly to flap its wings!

And since the layer is so incredibly thin, it gets an extra boost of support from a series of air-filled veins and tiny scales. These tiny scales help protect the wings, but also give different species of butterflies their distinctive color.