Batesian Mimicry - Aposematism

Aposematism

Most living things have at least one predator, with which they are in a constant evolutionary arms race to develop protective adaptations. Some organisms have evolved to make detection less likely; this is known as camouflage. Other organisms are not profitable for potential predators even if they do locate them. Some lizards, for example, will do 'pushups' if they are spotted, advertising to the predator just how strong and healthy they are - that pursuing them is just not energetically profitable. Still others however are harmful even if the predator can eat them, for example many plants and fungi contain deadly toxins and other chemicals, while certain snakes, wasps, and other animals are able to poison, injure, or otherwise harm many of the predators who would otherwise eat them. Such prey often send clear warning signals to their attackers, such as strong odors, bright colours and warning sounds.

Use of such messages is known as aposematism. Aposematic prey need not display such signals all the time. It may be energetically costly for them to do so, and even if it is not, they may have other predators that can tolerate their defenses. In fact, even if all their predators will avoid them if adequately warned, there are still those predators that have not yet learned that they are dangerous. Short of instinctive programming to avoid the aposematic organism (which is seen occasionally), it is unlikely that any potential prey will be prepared to sacrificially educate its predator. Thus, a combination of camouflage and its antithesis, aposematism, often occur.

However, once a predator has learned from harsh experience not to go after such prey, it will be likely to avoid anything that looks even remotely similar if it can. It is in this fashion that Batesian mimics have evolved. It is often misunderstood that such a mimic is somehow responsible itself for its mimetic characteristics. This is quite a serious misunderstanding, however. It is the duped predator that does the selecting, choosing to avoid those prey which look most like the aposematic model. In this way, the signal receiver directs the evolution of the mimic toward closer and closer similarity to the model.