Mimicry – the batesian way

In the last blog I talked about how some animals have adapted wonderful colors and patterns to warn off predators and advertise their distastefulness. This seems to be the perfect adaption to avoid predation, and it really works well, at least until someone else decides to take advantage of this. There is never a competition without cheaters, and in the animal world the stake is high, it's a matter of life or death, which makes winning very lucrative. So what happens when an animal with no defense mechanism start to mimic an animal which do have a good defense and very distinct color patterns? And why does this happen?

An animal with a good defense mechanism and strong recognizable color patterns (aposematism), will quickly teach a predator to stay away, there is no point in hunting something that is inedible. This is of course very beneficial for the prey. But through time the predator might as well stay away from other species with similar attributes, because the predator find them hard to distinguish from each other, and as a result it will stay away from all similar species. The look-a-like species, doesn't have to be in possession of any defending mechanism at all, it just gets benefits because predators think it is inedible. This means that individuals which best mimic the original species, will be the ones that survive, mate and pass their genes on to the next generation. What we end up with here, is to species who resemble each other, one with defense and one without.

The resemblance doesn't have to be exact, very often the colors are the same, but the patterns just look similar in a broad sense. A predator doesn't take its time to stop and count stripes or dots before attaching. Since it often spots the prey in a long distance, it would be time and energy consuming to move all the way up to the prey just to realize it is the real model of that animal, and then have to give up the hunt, and most animals are not even capable of telling the difference. This means that a predator who have tasted the real model with a defense mechanism, basically would give up everything that looks the same, and find something else.

This all sounds really good, and we might think mimicry is a very good strategy, it gains the defenseless species and doesn't seem to effect the original model. But is this really the case? Unfortunately not. The strategy works well if a predator tastes the original model first, and gets a very bad experience. But that is not always the case. Sometimes the predator might actually eat the mimicking species, and then it will get the impression of it being a very good meal. Instead of learning to stay away, the opposite is achieved, because a predator with a good hunting experience, is more likely to hunt the same kind of prey again. This puts the original model species at more risk, since the predator is not likely to distinguish between similar species, and therefor might try to eat original species as well.

Overall, having species mimic you is not good for your defense advertisement, since this seems to confuse the predator and weakens its perception about the link between color patterns and defense. If a predator sometimes catches a species that tastes good and other times something that is really bad and inedible, the link will be erased. Without any link, all species are very vulnerable, since they are very easily spotted, and this might not go in anyone’s favor. All gets eaten, and the predator will have to use time and energy on prey that is not always good for eating.

To make Batesian mimicry work, it is important that the mimicry species are less abundant compered to the original models, basically the mimicry species should be rare, so that most predators only encounter the ones with defense, and thereby making the aposematism work efficiently. The few individuals that mimic an original species, will then in most cases be protected because they don't encounter predators as often, and when they do, the predator is likely to already have tasted a bad version of it, and will then just stay away.

We humans also encounter mimicking species and the originals from time to time, and it's of importance that we learn which is which. That is because some species can be a real treat to us, while others are harmless. If you can't be sure which one is dangerous and which one is not, then play it safe, stay away.

Which of these do you actually think is the original with highly effective venom?

<http://www.scwildlife.com/pubs/julyaug2008/coralsnake.html>,  viewed 20 March 2014, photography by Steve Bennett

<http://www.wildflorida.com/wildlife/snakes/Scarlet_Kingsnake.php>, viewed 20 March 2014, photography by Alan Cressler.

These butterflies look very similar, but only the Monarch is distasteful.

<http://creationrevolution.com/2011/02/mirror-mirror-on-the-wall/>, viewed 20 march 2014.

Bibliography:

Gullan, PJ & Cranston, PS 2010, The insects: an outline of entomology, Wiley-Blackwell, West Sussex, UK.