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Uroplatus fimbriatus gecko in Madagascar. (Photo by R. Butler)
THE ARTS OF DECEPTION: MIMICRY AND CAMOUFLAGE
MIMICRY
There are three forms of mimicry utilized by both predator and prey: Batesian mimicry, Muellerian mimicry, and
self-mimicry. Mimicry refers to the similarities between animal species; camouflage refers to an animal species
resembling an inanimate object.
Batesian Mimicry
Batesian mimicry is named for Henry Walter Bates, a British scientist who studied mimicry in Amazonian butterflies
during the mid- and late nineteenth century. Batesian mimicry refers to two or more species that are similar in
appearance, but only one of which is armed with spines, stingers, or toxic chemistry, while its apparent double lacks these
traits. The second species has no defense other than resembling the unpalatable species and is afforded protection
from certain predators by its resemblance to the unpalatable species, which the predator associates with a certain
appearance and a bad experience. Examples of Batesian mimicry are the several species of butterflies that mimic
the toxic Heliconid butterflies. Another fascinating butterfly mimic is the non-toxic Papilio memmon of Indonesia.
Each female butterfly (regardless of her coloration) can produce one or more different female forms which mimic
any of five other species of foul-tasting butterflies. Batesian mimicry is also found in venomous coral snakes
and the harmless milk and king snakes of the New World. Both snakes are marked with alternating yellow, red, and
black bands causing possible predators to avoid both. The snakes can often be distinguished by using an old scout
saying: "Red against yellow: kill a fellow. Red against black: friend to Jack." The deadly coral snake
has bands in the order of red, yellow, black, while the innocuous species have the pattern of red, black, yellow
(although the rule is not foolproof and there are exceptions).
Muellerian Mimicry
Monarch butterfly on the left, viceroy butterfly on the right. Both taste bad to predators. (Photo by R. Butler)
Muellerian mimicry is named for Fritz Mueller, a German zoologist who worked in the Amazon three decades after
Bates. This form of mimicry refers to two unpalatable species that are mimics of each other with conspicuous warning
coloration (also known as aposematic coloration). Thus all mimics share the benefits of the coloration since the
predator will recognize the coloration of an unpalatable group after a few bad experiences. Since several species
have the same appearance to the predator, the loss of life will be spread out over several species, reducing the
impact on each individual species. Poison arrow frogs of South America and Mantella frogs of Madagascar are examples with their conspicuous coloration of bright
colors against black markings and toxic composition.
Picture examples of poison dart frogs and Mantella frogs
Owl butterfly (Caligo idomeneus). Note the conspicuous eyespot. (Photo by R. Butler)
Self-mimicry is a misleading term for animals that have one body part that mimics another to increase survival
during an attack or helps predators appear innocuous. For example, countless moth, butterfly, and freshwater fish
species have "eye-spots"?large dark markings that when flashed may momentarily startle a predator and
allow the prey extra seconds to escape.
"Eye-spots" also help prey escape predators by giving predators a false target. A butterfly has a better
chance of surviving an attack to the outer part of its wing than an attack to the head.
Less often predators utilize self-mimicry to aid in catching prey by appearing less threatening or fooling the
prey as to the origin of the attack. For example, several turtle species and the Frogmouth Catfish (Chaca sp.)
of Southeast Asia have tongue extensions that are used as a sort of lure to attract prey to a position where they
become an easy catch. One of the most interesting examples of self-mimicry is the so-called "two-headed"
snake of Central Africa which has a tail that resembles a head and a head that resembles a tail. The snake even
moves its tail in the way most snakes move their heads. This adaptation functions to trick prey into believing the attack
is originating from where it is not.
CAMOUFLAGE
A completely different approach for deception is camouflage, whereby animals seek to look inanimate or inedible to
avoid detection by predators and prey. There are many examples of rainforest species which are cryptically
colored to match their surroundings. For example, the Uroplatus geckos of Madagascar are incredible masters of
disguise and are practically unnoticeable to the passer-by. An even more amazing group is the katydids, a group
of grasshopper-like insects found worldwide. Katydids are nocturnal insects which use their cryptic coloration
to remain unnoticed during the day when they are inactive. They remain perfectly still, often in a position that
makes them blend in even better. Katydids have evolved to the point where their body coloring and shape matches
leaves?including half-eaten leaves, dying leaves, and leaves with bird droppings?sticks, twigs, and tree bark.
Other well-known camouflage artists include beetles, mantids, caterpillars, moths, snakes, lizards, and frogs.
Some species appear to have conspicuous coloration when they are not in the proper surroundings. For example,
among the brilliant butterflies of the forest, the magnificent electric blue Morpho, has iridescent blue upper
wings and a seven-inch wingspan. However, because the underwings are dark, when the Morpho flies through the flickering
light of the forest or even out in broad daylight, it seems to disappear. Other forest species, especially mammals,
have spots or stripes to help break up the animal's outline. In the shade created by the canopy, large mammals
like leopards, jaguars, ocelots, and okapi are surprisingly difficult to see with their disruptive coloration.
How falling a gecko lands on its feet
(3/17/2008) According to new research the gecko may have the most dynamic tail in the natural world. Two researchers from UC Berkley have discovered that the gecko uses its tail to keep itself from falling off slippery vertical surfaces and when falling to rapidly right itself. So, like a cat, it always lands on four feet.
Photos: Caterpillar transforms from mimicking bird droppings to a leaf
(2/21/2008) Scientists have discovered the hormone that enables swallowtail caterpillars to morph from mimicking bird droppings to the bright color form that matches the leaves upon which they feed. The research is published in Science.
Overfishing may hurt Amazon forest trees
(2/5/2008) Overfishing is reducing the effectiveness of seed dispersal by fish in the Brazilian Pantanal, reports Nature. The research suggests that fishing practices can affect forest health.
To reproduce, parasite transforms ant into juicy red berry
(1/17/2008) Scientists have discovered a parasite that transforms the appearance of its host, an ant, into that of a juicy red berry that birds are more likely to eat and disperse into new habitats, reports an article published in The American Naturalist. It is the first example of fruit mimicry caused by a parasite, say the researchers who discovered the parasite, a nematode or roundworm found in the canopy of tropical forests ranging from Central America to the lowland Amazon.
