What is Mullerian mimicry?

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Butterflies highlighting Mullerian Mimicry

Mullerian mimicry is a natural phenomenon when 2 or more harmful species, which may or may not be closely related, come to mimic each other in their external appearance to scare away the animal (predator) that is hunting. These animals have a common predator, and therefore experience mutual gain when their body patterns are associated with danger in the eyes of the predator, causing them to be passed by. The most commonly cited example of Mullerian mimicry is in butterflies, various lineages of which have similar colorful patterns on their wings to help scare away predators. The butterfly’s actual repel mechanism is its foul taste. It can be contrasted with ‘Batesian mimicry’, where a harmless organism imitating the protected species is referred to as the ‘mimic’ and the dangerous one being imitated the ‘model’. Mullerian mimicry differs because both parties are harmful; each mimics the other species, while serving as a model at the same time. If one species is encountered far less than the other, the more common species could be treated as the model and the other the mimic. Mullerian mimicry is one of many forms of mimicry employed by organisms to help them survive.

 

What is the History of Mullerian mimicry?

In 1861, Henry Bates first offered a theory that insects use mimicry to fool predators. He observed that some edible insects shared the same coloration as other inedible species. Since, predators learned to avoid insects with these color patterns, he argued, the mimics gained protection by displaying the same warning colors. This form of mimicry came to be called “Batesian Mimicry”. Almost 20 years later, Mullerian mimicry was proposed by the German zoologist and naturalist, Johann Friedrich Theodor Muller (1821-1897), always known as Fritz. Muller offered the first explanation for resemblance between certain butterflies. He observed communities of similarly colored insects, all inedible to predators, and theorized that these insects all gained protection by displaying the same warning colors. Therefore,if a predator eat one insect with certain coloration and find it inedible, it will learn to avoid catching insect with similar coloration.

 

What is Aposematism?

Aposematism means warning signals. Dangerous organisms such as wasps, poison frogs, etc. with these warning signals are avoided by predators, which quickly learn after a bad experience not to pursue the same prey again. Learning is not actually necessary for animals which avoid prey; however learning from experience is much more common. The warning signal makes the harmful organism easier to remember as “cryptic” as possible (being still and silent, providing no scent and blending in with the background). Crypsis is the ability of organisms to avoid observation by other organisms. Aposematism and crypsis are in this way opposite concepts, but this does not mean they are mutually exclusive. Many animals remain inconspicuous until threatened, and then suddenly employ warning signals, such as bright colors on their underside or loud vocalizations. In this way, they benefit from the best of both strategies. Snakes and amphibians have this dual strategy.

 

When will the Mimicry rings arise?

Mullerian mimicry rings may arise, in which multiple insect’s species from different families share common warning colors. When a mimicry ring includes many species, the probability of a predator, to catch one of the mimics will increase. While this may seem disadvantageous, it is actually quite the opposite. The sooner a predator samples one of the indigestible insects, the sooner it will learn to associate the colors of that insect with a bad experience.

 

What are some examples of Mullerian mimicry?

  • Atleast a dozen Heliconus butterflies in South America share similar color s and wing patterns. Each member of this long wing mimicry ring benefits, as predators learn to avoid the group as a whole.
  • The number of insects on the milkweed plant grown in any garden share the same red and black colors. These beetles and true bugs represent another Mullerian mimicry ring

 

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