Art of Disguise: Insect Camouflage & Mimicry

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A giant hole at the center and a log bridge over it looks perilous.

The scene that chills your blood is a painting—a work of trick art. Making use of optical illusion caused by reflection of light, trick art makes you mistake a planar work as a three-dimensional structure. A painting on a flat surface when seen in close-up can remind you of real situation in long-shot. Amazingly, just like this trick art, there are masters of disguise who are hidden around us, deceiving everyone’s eyes. They are insects.

For defense and predation, animals blend in with their surroundings or mimic other species. This is called camouflage—the use of any coloration or conformation for the user not to be easily seen in the natural surroundings. Soldiers in camouflage uniform or military camouflage tents disguising for their self-protection can give us a better understanding.

When it comes to camouflage, you may come up with the protective color of a grasshopper in the grass, but insects’ camouflage goes beyond your imagination. A well known example is the stick insect that completely deceives its predators. Having the body color of green or light brown, the long thin insect which rarely moves around resembles a twig. The leaf insect, which inhabits tropical regions as one of stick insect species, resembles a leaf as its name shows. They have nerves looking similar to the veins of leaves they inhabit, and you cannot see their internal organs even through the sunlight, so it is very hard to distinguish them from leaves unless they move.

Stick insect
Leaf insect

On an autumn day, a leaf among fallen foliage starts to move. What’s happening? An Uropyia meticulodina moth like a curled-up dead leaf is skillfully hidden. Even more astonishing thing is that the wings that look curled and three-dimensional are actually flat. No greater work of trick art is found in nature.

The leaf butterfly in the genus Kallima resembles a dead leaf. The upper side of its wings has beautiful colors and patterns like ordinary butterflies, but when it lands down with its wings closed, it looks perfectly like a dead leaf. With all their minute details—veins, mold specks, and even cavities, they really look like a dead leaf. The most remarkable thing about it is that no two butterflies have the same patterns—just like the way how every leaf looks different.

Animals usually attack the eyes of their prey; this is why butterflies make false eyes on the rear portion of each wing to make their predators mistake the spot as the head. It helps them survive though they lose part of wings from the attack. The eyes of raptorial birds on the wings of butterflies even look intimidating. The owl butterfly is the best example. The large eye-spot markings on each hind wing are mistaken for the menacing gaze of an owl watching from a branch; small birds are scared off by highly cryptic owl eyes with a large dark pupil and a golden iris.

What can you find on the wings of the Atlas moth? The tips of this saturniid moth, the world’s largest moth in terms of wingspan, bear a resemblance to a snake. Birds cannot approach it, seeing the snake that is as scary as an owl.

Owl butterfly
Atlas moth

Mimicry in insects is possible in various ways because they can fine-tune pigments in their skin. Unlike vertebrates that only use specialized cells to change colors, insects can make a pattern in high definition in the outer layers of their skin.

Every kind of insect, which we’ve not seen or heard of before, is hiding in the thickets, deceiving our eyes. They stealthily pose as plants, or sometimes deceive their enemies—raptorial birds or snakes—with their exquisite patterns.

Animal mimicry is considered as a type of adaptation of living organism to nature. Some biologists, however, say that it is too perfect to be simply explained as a result of adaptation. We are just taken aback to see their brilliant colors, fine effects of light and shade, and elaborate forms, which can put the work of the world’s best artist to shame. A delicate pattern on a butterfly’s slender wings, unbelievable mimetic skills of insects hiding themselves on branches or leaves! What are they telling us?

Sources
Peter H. Raven & George B. Johnson, Biology, McGraw-Hill Science/Engineering/Math, 2001
Peter Forbes, Dazzled and Deceived: Mimicry and Camouflage, Yale University Press, 2011