Our website is made possible by displaying online advertisements to our visitors.
Please consider supporting us by disabling your ad blocker.
Warning colouration
Warning coloration (or aposematism) is how animals let other animals know that they are poisonous or dangerous. It is the exact opposite of camouflage. Warning colors are usually some combination of red, yellow, black and white.
Alfred Russel Wallace, a British naturalist, explained it this way, in 1889:
- "The animals in question are possessors of some deadly weapons, as stings or poison fangs, or they are uneatable, and are thus so disagreeable to the usual enemies of their kind that they are never attacked when their peculiar powers or properties are known.
It is, therefore, important that they should not be mistaken for defenceless [sic] or eatable species... since they might suffer injury, or even death, before their enemies discovered the danger or uselessness of their attack. They require some signal or danger flag which shall serve as a warning to would-be enemies..." [1]
Wallace predicted that birds and other predators would reject conspicuous prey whilst accepting cryptic prey. Later reports confirmed this.[2]
Animals with warning colors move slowly and expose themselves to sight. The sluggishness and exposure helps to advertise their defense. Along with the color and behavior often goes the foul smell of their chemical weapons. The grasshopper Aularches miliaris is a very good example. Noxious caterpillars often have thick, leathery cuticles which help them to resist young birds making a 'test'. When the bird takes a peck, disgusting fluid seeps out from special glands on its back. The caterpillar (or other larva) will often survive such an attack, and the young bird has learnt a lesson it will never forget.[2] All in all, the predator is given good warning. Tests show that warning colors definitely do deter predators.[3]
Some individual animals will die or receive damage while birds or mammals on the attack learn about the connection between color and taste. However, if warning costs less than hiding, the animal benefits. And the advertising traits such as colors may serve other functions as well. The patterns may help mate identification within the species, for instance.
Warning coloration is the basis of two different kinds of mimicry: Müllerian mimicry and Batesian mimicry.
- ↑ Wallace A.R. 1889. Darwinism. Macmillan, London. p232
- ↑ 2.0 2.1 Poulton E.B. 1890. The colours [sic] of animals: their meaning and their use, especially considered in the case of insects. Kegan Paul, London. p170; p336
- ↑ Ruxton G.D. Sherratt T.N. and Speed M.P. 2004. Avoiding attack: the evolutionary ecology of crypsis, warning signals & mimicry. Oxford. p55 5.3 Chemical defences [sic].
Previous Page Next Page
