Howdy, BugFans,
Camouflage is defined as “concealment by disguise or protective coloring.” A simple phrase for a concept that manifests itself in a dizzying array of life forms.
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There are two reasons to be camouflaged–to hide from predators; and to be a more effective predator (of course, a camouflaged predator is evading its own predators). And there are two main categories of camouflage–crypsis and mimesis (there’s some overlap between the two). Cryptic animals resemble/blend into their surroundings; mimics benefit from resembling some other organism. Here are some of the categories and practitioners of the cryptic variety of camouflage. Next week—mimicry.
Changeable colors or patterns: Chameleons aren’t the only chameleons in the animal world.The common goldenrod crab spider (Misumena vatia) has a limited palette—yellow and white—and visual cues tell it which to select. To become yellow it must produce yellow pigment, a process that may take three weeks. Turning white is a shorter and easier process—white is a lack of yellow, accomplished by re-absorbing the pigment.
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Self-decoration: Some immature insects, like the nymphs of masked hunters and of a few species of green lacewing, and the caterpillars of Wavy-lined looper moths and Harvester butterflies decorate their exoskeletons with whatever materials are at hand. Like a Ghillie suit. The looper caterpillars escape predation by looking like bits of dry vegetation; the other three are predators whose disguises get them closer to their prey.
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Motion camouflage: Counterintuitively, some camouflage is attained by motion. Imagine that this dragonfly is not sitting, but flying straight at you. Whether approaching a meal or a mate, an insect that flies directly at its target seems not to move, only to get larger. The BugLady’s Major Professor gave her that same tip decades ago for photographing insects (Thanks, Dr. Fischer). Move straight ahead slowly, no bobbing or weaving or arm-flapping.
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Disruptive coloration: In many aquatic insects like the water boatman (as well as in ducks, loons, etc.) the belly is light, and the back is dark. To a predator looking up from below, the light underside resembles sky. To a predator above, the bug (or bird) is dark like the water’s surface. The stripes of a Black swallowtail caterpillar are another kind of disruptive coloration; it hangs out in dappled areas, and the stripes distort its body’s size and shape. Do the stripes of a tiger swallowtail in flight do the same?
Cryptic behavior: Walking sticks are undisputed champions of the camouflage world, but a motionless twig on a windy day invites investigation. Walking sticks will sway gently in the breezes. Sawfly larvae often curl up in groups on a leaf, leaving predators guessing where one starts and the other begins.
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Resemblance to the surroundings: If your habitat is green, be green; if it’s gray, be gray. Etc.
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Transparency: Or, you could just forget all the complicated colors and patterns and schemes and just be transparent, like the Phantom midge larva. Works best when you float just below the water’s surface.
The BugLady