Golden tortoise beetle: a special insect

'And then suddenly someone in Khanom or the South of Thailand, if you like, points me to a special insect that I didn't know existed', writes Monique Rijnsdorp. So she set out to investigate and discovered that the golden tortoise beetle has a unique system for changing color.

It is well known that many living creatures change color as a camouflage tactic. Living creatures like the chameleon and squid change color through modifications in some special cells that carry colored chemicals: pigment cells. But the method of the golden turtle beetle is different.

This insect is also known by the name charidotella egregia and can grow up to 8 millimeters. It features a transparent sleeve. This sleeve usually reflects the color metallic gold. But when the insect feels uncomfortable, the golden color changes to red.

Researchers at the University of Namur examined the insect's shell using an electron microscope and discovered that it consists of three layers. The thickest layer is the bottom and the thinnest is the top. Each layer consists of a package of smaller layers. Each layer reflects the light in a different color. Together, these reflections produce the color gold. Below these three layers is the red pigment layer.

There are channels between all layers. When the body fluid of the beetle fills these channels, the layers become smooth and, as Belgian scientist Jean Pol Vigneron puts it, 'perfect mirrors' are formed. This way the beetle looks shiny and metallic. When there is no liquid in the channels, the layers act as a window instead of a mirror, the sheath loses its luster and the lower red pigment becomes visible.

Andrew Parker of Oxford University describes this 'fluid-based mechanism' as 'one that has never been seen before in nature'.

Scientists expect to be able to develop devices that can show the liquid state through light and color in different situations, based on the technology in the golden tortoise beetle.

Radislav Potyrailo, an analytical chemist at the GE Global Research Center in New York, has this to say about this unique technology in the golden tortoise beetle: "Nature will never stop surprising us with elegant solutions to everyday problems."

Used sources:
Technology in the Golden Turtle Beetle, Muhlis Teker, plazilla.com
Color Changing Bugs, Emily Sohn, student.societyforscience.org