|
11-12 of 12 messages
|
Previous
Page 2 of 2
|
|
RE: Bothrops jararaca mimic?
|
Reply
|
|
by Cro on August 19, 2010
|
Mail this to a friend!
|
Very interesting question, Bryan.
I would think, that if this is indeed Real or True Mimicry, you would need to show that the mimic received a direct advantage by being such a close match to the Bothrops, that it would be avoided by predators that would also avoid the Bothrops jararaca.
I guess if we consider humans who might capture snakes as predators, then the resemblance to Bothrops jararaca just might keep a human from reaching down and picking up one of the harmless mimics.
But, are there other predators who would avoid these snakes due to their close resemblance to the Bothrops? That would imply a learned or taught behavior, which could happen if a bird of prey, or other animal received a non-lethal bite from the Bothrops, then avoided the mimics, and perhaps even taught its young to avoid the mimics, due to the strong resemblance.
Or, perhaps there is even a "genetic" memory that is hard wired in to cause potential predators to avoid certain patterns that are part of the coloration / pattern of the Bothrops ? There might be more to this than folks first think. Things like the red hourglass shape on widow spiders seems to accomplish that without it being taught, almost as if it is hard-wired somehow into the survival mechanisms of humans.
There also might be patterns that are not visible to humans, but, are visible to predators who can see parts of the spectrum that we can not see. I know that certain flowers have "land here" markings to direct bees to them, but, we can not see what the bee clearly sees on those flowers. Has anyone done any work with the same technology to see if there might be "hidden" signals in the patterns of snakes that are visible to some predators ?
And, what about scent ? Is it possible that the musk odors of the mimic snakes have also evolved to match those of venomous snakes, so, predators who use scent more than vision might obtain the same sort of protection from a dangerous snake ?
We also know that acoustic mimicry is seen in amphibians, birds, and insects. Sometimes, in duplication that is just as extraordinary as in the Bothrops pattern mentioned above, except it is sound instead of light. How does that happen ? Is it again just natural selection, where one mutant frog strangely sounds like another speies ? Or, is it a learning, that got somehow transferred ?
One form of mimicry would suggest that the animal might derive a benefit in obtaining food by being a mimic of another animal. In this case though, I would think that any cryptic patterned snake would have almost equal advantage in not being seen by lizards and frogs, and hunting skills, so, I would guess that type of mimicry would not be what is happening here.
Most likely, it is mimicry to derive protection by looking venomous while actually not.
In tropical forests, the complex coloration of the background would lead to complex patterns of the animals that have to blend in there. We can think of natural selection to contributing to these coloration and pattern over time, however, it is difficult to see that creating such complex patterns. I sometimes wonder if perhaps as a Chameleon sees a background, then changes coloration to match it, perhaps other reptiles somehow "see" the coloration of the background they live on, and "create" a genetic imprint of that, that becomes hardwired somehow into the genetic memory that is passed from one generation to the next, each generation getting closer to the perfect blend for that background color. It is hard to believe that natural selection could be fully responsible for such intricate patterns and coloration, and even more so, when we see examples of true mimicry as discussed above.
Lets go further out into the fringe. Lets say that there is something like I am proposing above in the genetic memory. What if one species preys on another species. Could some of that genetic memory be transferred to the predator, and contribute to future coloration and pattern of such an exact nature ? In other words, "you are what you eat" ? One might ask, which of these snakes has been around longest ? Is it the Bothrops jararaca, or, one of the mimics ? Does the DNA or fossil record support just how long these animals have had to become mimics ?
If natural selection is involved, then we would from time to time expect to see new coloration and patterns emerge, and we do see that in reptiles. And, if those coloration and pattern created an advantage, one could see that being passed on by the successful animal. But, that all takes time. A lot of time. That is why I wonder if something else might be involved. Something far more complex and "out there" than has ever been considered before.
Anyway, just a few random thoughts on the subject. Batesian, and other form of mimicry has always been a fascinating subject for me. This is just a topic that stirs up so many possibilities.
Best Regards
John Z
|
| |
|
RE: Bothrops jararaca mimic?
|
Reply
|
|
by CanadianSnakeMan on August 19, 2010
|
Mail this to a friend!
|
You could try examining accounts of prey that certain predators have been observed eating in their natural habitats. If the same prey animals avoid both species of snakes, it would be a good starting point for further research.
Also, if W. merremi displayed similar defensive behaviour to the jararaca that may point towards true mimicry.
Do the colours W. merremi match the variability of the jararaca (or is that even a consideration when taking a predator's eyesight into account)?
In Ontario, several species of snakes are known to mimic the Eastern Massassauga (the Fox snake for example). Not only are the patterns very similar, but they behave the same way when threatened - with the exception of delivering a venomous bite, that is!
|
| |
|
Email Subscription
You are not subscribed to this topic.
Subscribe!
My Subscriptions
Subscriptions Help
Check our help page for help using
, or send questions, comments, or suggestions to the
Manager.
|
