Introduction
The insect has evolved to become the most successful organism on earth. This could be linked to mainly two attributes, wings and size. The ability to fly has allowed the insect to spread throughout every point on earth and to escape predators easier. Their size also helped with better disguise (camouflage) from predators. It allowed them to hide in places large predators such as birds couldn’t get in. Insects perform many functions due to their diverse anatomies which have adapted to do anything.
Exoskeleton
The exoskeleton is the hard outer shell of the insect that provides support and protection. It also helps to regulate water loss and limit the size of insects. The insect exoskeleton is made up of a compound called chitin. Chitin is a close chemical relative of glycogen (basic human fuel) and cellulose (what wood is made of). The cuticle consists of three different layers and they are the endocuticle, the exocuticle and the epicuticle. The epicuticle is the outermost of the cuticles and the endocuticle is the innermost. During molting, the endocuticle is digested while the exocuticle is not.
Colors of Insect
Insect’s exoskeletons have different pigments that give them different colors. They are as follows:
- Melanin: yellow, brown, black
- Carotenoids: red, yellow, orange (hence the name carrot)
- Pterins: red, yellow, white
- Ommochromes: red, yellow, brown
- Anthraquinones: red, orange
- Aphins: red, yellow, orange and only confined to aphids
- Chlorophyll derivatives: green.
Since many insects can change color, they can control which pigment is expressed more. But not all do it this way. For example, the Hercules Beetle, Dynastes Hercules, can appear yellow green or black depending on the moisture in the atmosphere. Their epicuticle in their elytra is transparent, beneath it is a spongy yellow layer and beneath that is a black cuticle. During dry conditions, the spongy layer is filled with air and reflects back a yellow color. During humid conditions the spongy layer is filled with water, absorbs light and so the black is reflected. This is believed to be a camouflage adaptation since humid conditions are mostly at night.
