Eyes of a Snake?

Imagine that you are a small insect-eating bird foraging for dinner on the dimly lit floor of a Costa Rican rain forest. You come face to face with a pair of beady eyes. Study them for a moment.

If those eyes belonged to a snake, you would be dinner by now.

The face is not a snake's, but a caterpillar's. An uncanny resemblance - but, as it turns out, not a unique disguise. Begin the slide show for more examples of caterpillars or chrysalises that display false eye and face patterns mimicking those of snakes, lizards or other animals.

Images here: http://www.nytimes.com/slideshow/2010/06/11/science/20100615-creatures.html

landed on her neck.



THE EYED CLICK BEETLE

Thanks for the slideshow link, it was pretty interesting.

THE EYES HAVE IT Some of hundreds of species of moths and butterflies whose caterpillars or chrysalises display false eye and face patterns of predators.
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Imagine that you are a one-half-ounce, two-inch-tall insect-eating bird foraging for dinner on the dimly lighted floor of a Costa Rican rain forest. You come face to face with a pair of beady eyes. Study them for a moment. If those eyes belonged to a snake, that moment of study would mean that you would be dinner by now.

The face, however, is not a snake’s, but the chrysalis of a skipper butterfly. An uncanny resemblance — but, as it turns out, not a unique disguise.

In one area of Costa Rica alone, a team of researchers led by Daniel H. Janzen and Winnie Hallwachs of the University of Pennsylvania and John M. Burns of the Smithsonian National Museum of Natural History have discovered hundreds of species of moths and butterflies whose caterpillars or chrysalises display false eye and face patterns that mimic those of snakes, lizards or other animals. In a study published this week in The Proceedings of the National Academy of Sciences, they propose that this plethora of counterfeit patterns has evolved to exploit birds’ innate instinct to avoid potential predators.

The idea is a fresh twist on the well-established phenomenon of mimicry among animals. First described by the British explorer Henry Walter Bates in the 1860s (the subject of my column on Feb. 16), the original insight was that harmless, edible species could gain protection from predators by resembling distasteful, noxious species.

Bates assumed that for this mechanism to work, the potential predators had to learn which prey in their range were to be avoided. And the potential prey — say, a large, colorful adult butterfly — must closely resemble the inedible species it mimics.

But when it comes to a deadly encounter with another species, there may be no second chances, no opportunity for learning. Hence, natural selection would favor instant recognition, and hard-wired rapid responses, in a close encounter with potential danger. Harmless creatures that evolved some general resemblance to the variety of creature features to be avoided (eyes, scale patterns) would then gain some protection.

Dr. Janzen and colleagues have cataloged a delightful assortment of striking false eye patterns on the front and rear ends of caterpillars and the front ends of chrysalises.

Their bounty and insights are the product of a dedicated, and somewhat accidental, long-term study of the denizens of the Área de Conservación Guanacaste, or A.C.G., in northwestern Costa Rica.

It began in 1978, when Dr. Janzen broke some ribs falling into a ravine while conducting field studies in the region. The road to the hospital was too rough to navigate, so he wrapped his sore rib cage and confined himself to a chair for a month.

Unable to explore the rain forest, he soon went a bit stir-crazy. The field station had only two hours of electricity each night, and just enough power to run a 25-watt light bulb. Fortunately for Dr. Janzen, that was a bumper year for moths, which were attracted to the light. So he passed the time building a moth collection.

More: http://www.nytimes.com/2010/06/15/science/15crea.html

thought so, I don't want to either

rec