These stunning insect close-ups reveal dazzling bug complexity
Hard yet flexible, chitin builds insects’ exoskeletons, wings, and scales.
In the metallic wood-boring beetle (Eurythyrea quercus), its iridescent wing casing and abdomen contain chitin, a substance that provides armour-like protection.
Arthropods are the most diverse group in the animal kingdom. Among them, the evolutionary record holders are the insects, thanks to their ability to adapt to many different ecosystems both in water and on land. The versatility of arthropods is due in large part to chitin, a substance that forms their hard outer covering as well as their wings and other flexible parts. Like cellulose, the building block of plant cell walls, chitin is made of glucose molecules, but it also contains nitrogen, producing a firm structure.
It’s a mystery how the cuticle of the jewel beetle (Anthaxia croesus) gets its dazzling colour. Proteins likely bonded with chitin to produce the hues. Most of these photos were made with a microscope lens. Dozens of photos were stitched together to create a single composite image, revealing the subject's minute details in sharp focus.
The shiny chitinous armour of this pseudoscorpion known as scissorhands (Neobisium sp.) hides a tiny insectivore. This animal appears frightening, but unlike true scorpions, its stinger is not poisonous.
The chitinous scales of this butterfly’s wings (Chrysiridia) form gratings that create metallic colours.
A hornet’s compound eye is made up of thousands of lenses composed of chitin.
Chitin is the main component of the arthropod’s exoskeleton, the first rigid form to evolve in multicellular organisms: arthropods made chitin as early as 550 million years ago. Secreted by the epidermis, or skin-like, soft outer layer, chitin combines with other compounds to form the waxy, water-repellant cuticle.
The feathery antennae of a red click beetle (Anostirus purpureus) are made of the flexible form of chitin.
The multipurpose appendage of a jewel beetle has chitinous armour in the form of its spurs and claws.
To the naked eye, this green immigrant leaf weevil (Polydrusus formosus) appears to have a green cuticle. A closer look reveals that dense, chitinous scales give it colour.
A remarkably hard yet flexible material, chitin strengthens insect mandibles to cut through rock and metal, and provides elasticity between the stiff body segments, enabling speed and agility. The tiny, delicate scales covering insects such as butterflies also contain chitin. It’s integral to the thin tracheal tubes that make up their respiratory system and the hairs that collect pollen.
It seems chitin can do almost anything—except allow an exoskeleton to expand. So, in order to grow, arthropods must moult. Every so often they have no choice but to temporarily shed their protective chitinous covering in exchange for a little bit of room to grow.
This story was originally published in the June 2021 issue of National Geographic’s Hungarian edition.
