# Study Suggests Habitat Degradation=Toxicity Degradation



## r90s (Jun 13, 2006)

Information concerning this I avaliable by clicking the link below.

http://news.mongabay.com/2006/1002-frogs.html



> Poison frogs less toxic when habitat degraded
> mongabay.com
> October 2, 2006
> 
> ...


Clyde


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## elmoisfive (Dec 31, 2004)

Very interesting and I hope that further studies are performed to see if the lower toxicity of frogs found in the disrupted areas leads to greater predation and if so how long that transition takes to occur.

While I suspect that many animals avoid brightly colored prey as potentially poisonous, I suspect that a number of them learn from practical experience that 'bright colors = bad taste and worse'

Thanks for sharing this info with the board.

Bill


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## Roadrunner (Mar 6, 2004)

there are mimics that do quite well taking the colors of the poisonous look alike. the monarch butterfly and viceroy around here come to mind. 
it would be interesting to see a study on them w/ the monarchs dissappearing but i think that is just butterflies in general and dont know if there is a predatory problem there.
w/ the terribilis you would think it would be instinctive since not much would live after munching one to "learn" it`s not good.
it may have different affects on different groups. mantellas seem to be worried about since a predator may be able to eventually sneak past the defenses but nature has always played this cat and mouse game just not at such a fast rate. predators evolve and prey evolve to one up them. on the other hand some darts(pumilio and auratus) seem to do well in disturbed areas. or should i say some pumilio and some auratus. the blue auratus along the panama canal? the original blues seem to have disappeared or are very threatened from what ive heard. the blue jeans seem to be found around garbage cans. i`m sure some have evolved toward more pristine settings are doomed or will have a hard time w/ the changes occuring and the morphs/species that can thrive in it will.


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## Blort (Feb 5, 2005)

Here is something recent that is relevant:

http://texas.amphibiatree.org/?q=node/125#attachments

Abstract:


> Batesian mimicry—resemblance of a toxic model by an edible mimic-depends on deceiving predators. Mimetic advantage is considered to be dependent on frequency because an increase in mimic abundance leads to breakdown of the warning signal. Where multiple toxic species are available, batesian polymorphism is predicted—that is, mimics diversify to match sympatric models. Despite the prevalence of batesian mimicry in nature, batesian polymorphism is relatively rare. Here we explore a poison-frog mimicry complex comprising two parapatric models and a geographically dimorphic mimic that shows monomorphism where models co-occur. Contrary to classical predictions, our toxicity assays, field observations and spectral reflectances show that mimics resemble the less-toxic and less-abundant model. We examine "stimulus generalization" as a mechanism for this non-intuitive result with learning experiments using naive avian predators and live poison frogs. We find that predators differ in avoidance generalization depending on toxicity of the model, conferring greater protection to mimics resembling the less-toxic model owing to overlap of generalized avoidance curves. Our work supports a mechanism of toxicity-dependent stimulus generalization, revealing an additional solution for batesian mimicry where multiple models coexist.


The whole article is available through that link.


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## ColombianFrogger (Jul 9, 2004)

I have similar reports, of Phyllobates species being less poisonous when living in degraded habitat. Indians from Northeast in the Chco told me that in some deep forests, the poison of bicolor is nearly poisonous as terribilis, so you have not to kill the frog or burn it to poison the darts, just rub the dart tip on the frog back.


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