Mertensian mimicry

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Zach_Lim
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Mertensian mimicry

Post by Zach_Lim » July 14th, 2014, 12:38 pm

I was reading through some old herpetology papers and stumbled across a reference to "Mertensian mimicry".

Not really sure about it, I did a quick online search and found some information, including this excerpt from Wikipedia (I know..what a source haha!):

"Emsleyan[7] or Mertensian mimicry describes unusual cases where deadly prey mimic a less dangerous species. It was first proposed by Emsley[32] as a possible answer for the problem[which?] of Coral Snake mimicry in the New World."

So apparently, "This scenario is a little more difficult to understand, as in other types of mimicry it is usually the most harmful species that is the model. But if a predator dies, it cannot learn to recognize a warning signal, e.g. bright colors in a certain pattern. In other words, there is no advantage in being aposematic for an organism that is likely to kill any predator it succeeds in poisoning; such an animal would rather profit from being camouflaged, to avoid attacks altogether. If, however, there is some other species that is harmful but not deadly as well as aposematic, the predator may learn to recognize its particular warning colors and avoid such animals. A deadly species will then profit by mimicking the less dangerous aposematic organism, if this results in fewer attacks than camouflage would."

Anyone have any thoughts about this? The example given was that of a milksnake being the model for a coral snake's mimicry/pattern. Wouldn't a predator, under this model, easily eat a milksnake and realize all tricolors are edible/not dangerous?

I fail to see how this works.

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Jeremy Westerman
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Re: Mertensian mimicry

Post by Jeremy Westerman » July 14th, 2014, 3:01 pm

yeah I feel like tricolor snakes and corals would be an example of Batesian mimicry of harmless copycats mimicking a potentially dangerous species not the other way around. Did you find any other examples? As a wildlife biology/ecology major in college, I have never heard of Mertensian mimicry. it does sound like it encompasses other types of mimicry from a quick glance at the wiki entry.

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Jeff
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Re: Mertensian mimicry

Post by Jeff » July 14th, 2014, 5:00 pm

Zach

The Mertensian model was discussed in a 1966 German paper by Robert Mertens. It was also discussed in the 1970s by Emsley, a zoologist in Trinidad (working with Coral Snakes and mimic Erythrolamprus). The model are Coral Snakes (dangerously venomous) and the mimics are various tricolor Colubrids/Dipsadids. Mertens evaluated snakes that were brought to the Instituto Butantan in Sao Paulo (presuming equality of collection) during the early 1950s. Raw counts were about 4:1 mimics/models. However, when Mertens assigned the rear-fanged species with the Coral Snake models, and left the harmless species as mimics, the ratio was reversed. Thus, Mertensian mimicry supposes that painful, mild envenomations from rear-fanged tricolors is beneficial to their mimics, whether harmless or dangerously venomous, because individual predators learn to avoid snakes with tricolor patterns.

That's the theory, and it is open to discussion. A guy that I knew at San Jose State U back in the 1970s, Mitch Vickers, did a masters study that hypothesized the tricolor kings were bad-ass predators, and coral snakes mimicked them to be safe. His proposed experimental design was destroyed by Lab Animal use and school safety protocols.

Jeff

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Kelly Mc
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Re: Mertensian mimicry

Post by Kelly Mc » July 15th, 2014, 1:24 am

This is really interesting. how specifically our own criteria, like our cannonized assessments of predation and danger, may be actions that are actually contra percieved and adapted to by other species.

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monklet
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Re: Mertensian mimicry

Post by monklet » July 15th, 2014, 3:12 pm

There's one example in the bird world that I'm aware of and that is the apparent mimicry of Turkey Vulture by the Zone-tailed Hawk, which often mixes in with Turkey Vulture flocks. The overall color pattern (aside from the white tail bands) and the flight style whereby the wings are held in a shallow dihedral, make it hard to tell the difference at a distance, presumably permitting closer approach to wary prey items.

Edit: I misinterpreted Mertensian Mimicry ...so the above is not a valid example ...BUT, it's a cool example of mimicry in either case. Guess the would be "Aggressive Mimicry", or "wolf in sheep's clothing" mimicry. ...does anyone care? :lol:

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Joseph S.
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Re: Mertensian mimicry

Post by Joseph S. » July 18th, 2014, 9:11 am

Alternately it could be explained by the innate aversion hypothesis. Perhaps the bright coloration of deadly corals drove the evolution of general fear towards brightly colored snakes display by birds.

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