Mimicry in the Swamp

In the spirit of October and the impending dress-like-your-favorite character/star/dog/fruit day, let’s talk about mimics at Corkscrew, of the non-human animal variety. I typically don’t think about Halloween until the day after (when all the candy is on sale, duh), but this gives me a good excuse to talk about evolutionary strategies, and no one in their right mind would pass up an opportunity like that … right??



Cemophora coccinea coccinea (Photo Credit: Lee Martin)

So let’s get to it. Most people can think of an example of mimicry, like the palatable Scarlet Kingsnake (Lampropeltis elapsoides) or Florida Scarlet Snake (Cemophora coccinea coccinea) mimicking the coloration of the unpalatable Eastern Coral Snake (Micrurus fulvius) to avoid predation. Mimicry is an evolutionary tool employed by some animals, both prey and predator species alike, to either avoid predation or, in the case of predators, lure prey into a false sense of security to make predation more successful. But what makes a mimic a good mimic? Is there such thing as a bad mimic, or are there situations where a bad mimic is still effective? A good mimic, in theory, would closely resemble the harmful species, or model, with mimetic advantage decreasing as similarity to the model decreases. 


Model Danaus plexippus (PC: Lee Martin)

There are two common types of mimicry, Batesian and Müllerian. In Batesian mimicry, the palatable or harmless species mimics the harmful model to trick predators into thinking it is also harmful. In Müllerian mimicry, both mimic and model are unpalatable and develop similar physical traits to benefit from shared protection. Monarch (Danaus plexippus) and Viceroy (Limenitis archippus) butterflies are 

Müllerian mimic Limenitis archippus (PC: Lee Martin)

an example of this, because both are toxic and therefore unpalatable to potential predators. Regardless of the type of mimicry, mimics must be sympatric to models (occur in the same areas) to benefit from their protection. There must also be a sufficiently high frequency of models to mimics, so that predators have enough experience with the dangerous model to reinforce aversion to the warning signal. Otherwise, predators learn that the warning signal is a ploy, and there is no longer any mimetic advantage. However, there are always situations that bend the rule.

Many mimics have ranges that extend beyond that of their model, and individuals that exist in these areas are called allopatric mimics. Müllerian mimics are still harmful without a model, so aposematic (warning) signals would remain an effective strategy in allopatry. Batesian mimics do not have this protection, but may still benefit from mimicry when predators have an innate aversion to the mimicked trait, or if the trait has some other selective advantage such as enhancing crypsis or increasing resource acquisition. Finally, some predators that have large home ranges may come into contact with the harmful model where mimics are sympatric, and thus still avoid mimics in areas where the model is not present.

Many animals at Corkscrew display mimicry, from Scarlet Kingsnakes to Viceroys. Discovering the mechanisms that cause such phenomenon to occur is fascinating and remains somewhat speculative in nature. There is much we have yet to learn about these evolutionary processes, and the best thing? It’s happening right in our backyard!  

- Randi Bowman, Research Intern