# Theories abound, Let have some fun



## EDs Fly Meat (Apr 29, 2004)

Hey all,
I was talking dart frogs with a co-worker who loves to argue and play the Devil's advocate. She has a B.S. in bio-chemisty and Math. Is a Medical Doctor and Cardiac Interventional Fellow (which she jokingly says) makes her an expert on everything. 

The topic was batrachotoxins in dart frogs. I argued that it was diet related and she argued that it could be a catacholamine response. I.E. Fight or flight induced. Her hypothesis is that these frogs produce toxins in the wild due to their constant fight for survival, and that the reason they lose their toxicity in captivity is because of the lack of predators in captivity. The constant fight for survival is gone, so the ability to produce toxins is atrophied. In the professional breeders series there is a great chapter on batrachotoxins and there is mention of terriblis being toxic for months (it may be years) after captivity. I agrued that dart toxins vary seasonally, and her reply was that so do predators. Ergo various catacholomine responses would vary.

This of course supporting her weak albeit interesting arguement.

So lacking a volume of John Daly's published works on me. Lets have some fun and argue. And please please please. This is for fun. No "you're an idiot" comments besides thats too easy.


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## Guest (Mar 3, 2005)

If the toxin was created by stress each time we got a frog that was shipped we would have an extremely toxic frog. Because shipping is probably just as stressful as be carried around in the mouth of an animal.
Just an idea though.


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## EDs Fly Meat (Apr 29, 2004)

*Well*

Ok, 
How do you know they not?
Dave and Gretchen


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## Ben_C (Jun 25, 2004)

Hmmm....
Well, I don't have more than like 5 minutes, so this is going to be grammar/punctuation challenged and may not be as logical as I hope, but here goes...
First, it seems to me that if it were a "fight or flight" response that the synthesis of batrachotoxins would take a little time and if a predator stumbled upon a dart frog who was not producing toxins, the predator could swallow the prey w/o even knowing that it is toxic and the frog could die before producing these toxins. She is the biochemist, however, so the synthesis could happen much faster than I'm imagining, however if it is a predator that bites the frog and crunches it straight away, it seems that there would not be enough time for a response (creation of toxins).
Sorry for this being so poorly written, but I figured that going through and editing for punctuation, etc. would just be a waste of time as this is not a real formal debate.
Secondly, fight or flight responses are typicall associated with the inhibition of immune function, digestion, reproduction, and growth. Looking at populations in the wild, we can see that these frogs DO have (functioning) immune systems, DO digest, DO reproduce, and DO grow...
However, we can't rule out your MD's hypothesis (without experiments) because it is entirely possible that they synthesize these toxins and keep them in vessicles near the surface of the skin. When a Fight or FLight (FF) response occurs, it could be neurally controlled and the toxins could be kicked out immediately.
I guess the key would be to look at the COST associated with synthesis of batrachotoxins. If it is metabolically costly to manufacture them, the FF response scenario seems to be one that would be selected for. However, if toxins are plentiful in the diet and the frogs needed to dispose of them somehow and secretion across the skin was easier than excretion in urine/feces/whatever, then they could always secrete the toxins independant of a FF event.
Basically this is a cool topic but we're only speculating because it'd be cheating to either: a) propose experiments to test this hypothesis or b). cite other peoples work that supports one hypothesis or another.
So again, to go over the above points again, it is impossible to take a side in this argument without knowing the costs of synthesis of batrachotoxins and an idea as to what selective pressures led to the secretion of them.
Sorry I skimmed over the ideas i had really quickly, but there ya go!
Anyway, was this what you were looking for, Mr. Fly Meat Inc? 
~B


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## Guest (Mar 3, 2005)

Because I know People are not as good at cleaning there hands as they think (ask any doctor). And I have not heard of someone getting sick or die after handling one of the deadly trio (cb). But it also could be alittle bit of both like it does not actually secrete the toxins that it got from it's food sources until it is stressed. I guess it really could go both ways?


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## EDs Fly Meat (Apr 29, 2004)

*Hmm*

Thanks for the replies, great retort Ben. Yes this is what Mr. Fly Meat wanted.

So along with the millipede and ants. Is this something we should look into?
Dave


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## Will (Feb 15, 2004)

Here is the definitive test:
Bring you friend home to your collection, pick out one frog and harass the poor sucker. Since your position is that toxicity is diet related, you will lick the frog. Since she is an MD, she can treat you if her prediction is right. 

I think the simple answer is both positions have a level of truth. Dart toxins are a cocktail, some components might not be diet related, while others have been proven to be diet related. From what I hear a CB terriblis can still release a toxin that will ruin your day if ingested, but will not have the devastating effects of a wild specimen. So critical, lethal, components are missing which need to be synthesized from diet.


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## Darren Meyer (May 22, 2004)

Hey Dave , who's Gretchen ? Erin change her name ? 
Darren


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## EDs Fly Meat (Apr 29, 2004)

*nice*

LOL

Here is the definitive test: 
Bring you friend home to your collection, pick out one frog and harass the poor sucker. Since your position is that toxicity is diet related, you will lick the frog. Since she is an MD, she can treat you if her prediction is right. 

Thanks Will but I think I will pass.


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## dmartin72 (Oct 27, 2004)

Maybe Gretchen is the MD.


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## mindcrash (Mar 3, 2004)

Please, while licking the frog, have someone take pictures and post them here.


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## bbrock (May 20, 2004)

/


Dumbacher, J.P., A. Wako, S.R. Derrickson, A. Samuelson, T.F. Spandle, and J.W. Daly. 2004. Melyrid beetles (_Choresine_): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds. PNAS 101:15857-15860.


There's a beetle found in New Guinea that is the source of batrachotoxin for the Pithuoi bird. These beetles also occur in Colombia and are likely the source for dendrobatid batrachotoxin as well but it is current too dangerous to do the field work to confirm.

An earlier, but recent (citation not handy but I can get it from home), Daly paper revealed a number of pumiliotoxin alkaloids in soil arthropods and there was a match between the alkaloids found in arthropods in various locations with the pumilio that would be feeding on them.

Almost all, if not all, alkaloids are plant derived. Few, if any, animals are capable of synthesizing them. PDF toxins are alkaloids.

WC PDF retain toxins for months to years in captivity. Some species conserve the toxins better than others.

PDF are not without stress in captivity. Humans are potential predators. We should see predator induced stress every time a frog flees from us.

Finally, the fight or flight theory does not fit evolutionary history. Anuran toxin almost certainly evolved as an immune defense mechanism to ward off fungal and bacterial infections. Therefore toxins must be present in the skin at all times to perform this antimicrobial function. Although it would be possible to evolve a stress-induced delivery system to the skin, a much simpler evolutionary explaination is simply that the frogs evolved the ability to sequester increasingly toxic alkaloids in their skin.

I think Daly has put in about 30 years of research on this one and I think he's made a convincing argument for a diet based source. But I hope you bet a beer or something on this.


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## mydumname (Dec 24, 2004)

I would compare the release of toxins to sweat. When people exert energy or get nervous, sweat just comes out. The frogs get frightened, toxin comes out. It is a defense mechanism, sweat is a cool down mechanism. Frogs still get stressed in captivity, but don't have the toxins to release anything. This would mean that it is not naturally produced, but something environmentally related, in my opinion. The predator thing doesn't make sense because aren't we a predator. I had something else to say but I forget it. 

An odd thought:
Maybe the frogs aren't toxic in the wild, now hold on. Say they are immune to certain toxins in their diet/environment. They consume this toxins and as their immunity defense, somehow excrete it through their skins. But then that wouldn't make sense why terribilis release more when put in the fire or whatever they do to them. I am basically thinking out loud here. Maybe someone sees where I think I am going.


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## Blort (Feb 5, 2005)

This is an interesting quote:



> In a study published last week in the Proceedings of the National Academy of Sciences, researchers report that they have found batrachotoxins in a little-known group of beetles from the Choresine genus. The discovery marks the first time the toxin has been found in an insect.


http://news.nationalgeographic.com/news ... etles.html

I think what others are saying is right, that it is probably a combination of the the two events, diet and stress. Much of the information about getting poison from terribillis for hunting involves stressing the frog out before swabbing its back for poison. I wonder if the glands swell if poison isn't released like with poisonous snakes, if they stop production in a non-stress environment, etc. More than sweat glands, though, I would compare them to adrenaline glands.

Somebody else is going to have to figure it out because you can count me out of the frog-licking experiments :wink:

I think an equally interesting poison is that of the blue-ring octopus produced by bacteria.


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## bbrock (May 20, 2004)

Blort said:


> Much of the information about getting poison from terribillis for hunting involves stressing the frog out before swabbing its back for poison.


I'm not aware of documentation for stressing terribilis to extract the poison. The papers I have read indicate the dart tip is simply swabbed across a living animal's back. Of course handling alone will induce stress. However, it is my understanding that bicolor are skewered to get them to release concentrated amounts of toxin. Aurotania are skewered and thn heated to do the same. It seems there is a negative correlation between the strength of the toxin and the amount of stress needed to obtain sufficient concentrations to tip darts. Perhaps there is a citation for stressing terribs that I missed.


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## ETwomey (Jul 22, 2004)

The idea that the toxins are a result of 'the struggle to survive' is illogical, all scientific knowledge aside. If toxins were being produced from the stress caused by constant risk of predation, then the frogs would be toxic as hell, so they would not be eaten. Thus they would have no stimulus to produce toxins. Interesting topic though, tell this fancy pants MD to humble herself before the mighty Dendroboard!


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## Guest (Mar 4, 2005)

I don't see these two hypotheses as mutually exclusive. The synthesis of toxins is clearly somehow related to stress. A bunch of people have "overhandled" a newly arrived import in the past, only to have it start secreting toxins. On the same note, many in the hobby have "overhandled" and stressed out LTCBs and CBs and not experienced the joy of being toxed. Maybe their wild diet makes them a little more hot/ornery, and they don't feel as bad hitting the switch 

~Joe



ED's_Fly_Meat_Inc said:


> Hey all,
> I was talking dart frogs with a co-worker who loves to argue and play the Devil's advocate. She has a B.S. in bio-chemisty and Math. Is a Medical Doctor and Cardiac Interventional Fellow (which she jokingly says) makes her an expert on everything.
> 
> The topic was batrachotoxins in dart frogs. I argued that it was diet related and she argued that it could be a catacholamine response. I.E. Fight or flight induced. Her hypothesis is that these frogs produce toxins in the wild due to their constant fight for survival, and that the reason they lose their toxicity in captivity is because of the lack of predators in captivity. The constant fight for survival is gone, so the ability to produce toxins is atrophied. In the professional breeders series there is a great chapter on batrachotoxins and there is mention of terriblis being toxic for months (it may be years) after captivity. I agrued that dart toxins vary seasonally, and her reply was that so do predators. Ergo various catacholomine responses would vary.
> ...


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## Ed (Sep 19, 2004)

With bicolor and aurotania, the concentrations are less in the skin so more has to be extracted to reach an effective dose. This is why the frogs are skewered and cooked. 

Production and secretion are two different issues. Production will be controlled by a biological feedback mechanism. Secretion can be stressed related. The granular glands in all anurans can respond to stress with an increased secretion of the toxins. 
As these compunds are either sequestered and secreted unmodified or in some species are modified, as long as the frog is no longer provided with a supply of the toxin or its precursor it cannot store/produce/or secrete it. 

One of the main reasons it can take so long for a wc frog to lose its toxicity is that it is recycling the toxins each time it sheds and eats its own skin. The toxins are not being lost. 


Ed


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## bbrock (May 20, 2004)

mydumname said:


> An odd thought:
> Maybe the frogs aren't toxic in the wild, now hold on. Say they are immune to certain toxins in their diet/environment. They consume this toxins and as their immunity defense, somehow excrete it through their skins. But then that wouldn't make sense why terribilis release more when put in the fire or whatever they do to them. I am basically thinking out loud here. Maybe someone sees where I think I am going.


Well, you may be thinking out loud or you may have been cheating on your test because that is exactly how it happens. This stuff has all been documented in the literature. Nice stab in the dark!


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## bbrock (May 20, 2004)

Ric Sanchez said:


> The idea that the toxins are a result of 'the struggle to survive' is illogical, all scientific knowledge aside. If toxins were being produced from the stress caused by constant risk of predation, then the frogs would be toxic as hell, so they would not be eaten. Thus they would have no stimulus to produce toxins. Interesting topic though, tell this fancy pants MD to humble herself before the mighty Dendroboard!


I'm impressed! Nicely done!


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## Marty (Feb 27, 2004)

I see you watched "THE MOST EXTREME" on Discovery few days ago 

I did find someting interesting though, read the quote:



source from the link below for what it's worth said:


> It is interesting to note that frogs of the genus Phyllobates that are reared in laboratory situations completely lose their toxicity by the second generation, indicating the inability to synthesis the toxins de novo {Bartram, 2001). When Daly fed laboratory reared frogs small amounts of batrachotoxins the toxin accumulated in their skin, indicating the source of batrachotoxin existed in the frogs’ natural insect diet



Here is the link to some Student Review articles @ colorado state U.

EDIT: Here is something more solid. Link to an abstract

argh...I better go to bed, I'm wastin' time again :roll: 




bbrock said:


> /
> 
> 
> Dumbacher, J.P., A. Wako, S.R. Derrickson, A. Samuelson, T.F. Spandle, and J.W. Daly. 2004. Melyrid beetles (_Choresine_): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds. PNAS 101:15857-15860.
> ...


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## EDs Fly Meat (Apr 29, 2004)

*Wow*

Great replies. Very interesting.

I was a little thrown back by the Pithuoi bird discovery. It sounds like they did find the source for the bird. But that bird is in New Guinea. The same family of beetle is in the Columbian area, but is it toxic? Also, it's not the same beetle. And I have not seen many darts munch down an adult beetle. Let alone a bunch. It is a stretch, and the authis of most of the articles admit this. But, it may indeed explain why the Phyllobates are toxic, but what about the histrotoxins, and pumiliotoxins of the these respective frogs. I am not buying a pumilio chowing down on Melyrid-like beetles. No way.

It has alway boggled my mind as to why stomach content analysis has failed when studying the Phylobates. I have never tried so I cannot say, but I doubt that they digest chitin (anybody know?). There are ways to key out insects, and other invertibrates from parts, and body fragments but its a pain. _That I have done_, and earned my "C" proudly thanks again for the lesson in humbleness Dr. Kistner. Yet I have not seen any literature on the subject so it must not be effective.

John Daly in a great talk at IAD suggested that it is an ant or a millipede. He based that hypothesis off of molecules known to be produced in ant and millipedes, and that they were also found in frog toxins. Similar molecules not easily made, or are they? 

My hypothesis has been that the frogs do indeed get toxins from their diet but break apart the toxins again and again and re-arrange them into something entirely new. It eats an ant, or a grub, or small caterpillar that is toxic and machines it into a workable cocktail of batrachotoxin. But doing something like that would need radioactive isotopes. They did a similar experiment in plants to find out where the oxygen came from during photosynthesis. The argument was CO2 vs Water. But a similar experiment for frogs? Well, I'm sure there are several PhD's in there somewhere.

Time will tell. Thanks for the input. Keep it coming


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## EDs Fly Meat (Apr 29, 2004)

*But...*

But Ric whether we argue if it stems from a catacholamine reaction or diet, it is still a defence mechanism. An interesting point. 



> If toxins were being produced from the stress caused by constant risk of predation, then the frogs would be toxic as hell, so they would not be eaten.


Why would they not be eaten? If a predator ate one and lived it learned a vaulable lesson. I.E. "avoid the chubby, orange ones." If it ate one and died? Well, what would keep the frog from evolving and continuing to make toxins? 

Your thoughts?
Dave


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## bbrock (May 20, 2004)

Dave,

See:

Daly et al. 2002. Bioactive alkaloids of frog skin: Combinatorial bioprospecting reveals that pumiliotoxins have an arthropod source. PNAS. 13996-14001.

This is the paper I mentioned earlier. Cocktails of soil arthropods were analyzed for pumiliotoxin in several locations. Pumiliotoxins were found in the arthropods and the variations in the chemicals found matched the pumiliotoxins of the frogs in those same locations. Not only is it strong evidence the toxins are derived from food, it also suggests the toxins are simply sequestered unmodified.

As for the melyrid beetles. They are tiny and could easily be consumed in quantity by frogs. I sent the PNAS paper to an entomologist friend when it came out and he said these beetles are varied (lots of species) and widespread but the interesting thing is that the have strange pustules that nobody has figure out what they are for. He thinks it is very plausible that in some species they may be used to store alkaloids. The problem with getting the proof or doing stomach analysis on terribilis is that the area of Colombia where they live is unstable and dangerous. Only scientists who don't mind being kidnapped dare tread there. However, the Pithuoe link is compelling to me because these birds and the frogs are the only known animals to contain batrachotoxin. The fact that the bird's source has been identified suggests that searching Colombian melyrids would be a very likely place to look.

I am satisfied that Daly is starting to zero in on some of the sources for the toxins in PDF. There is still much to be learned. The paper above did not find any of the major pumiliotoxin chemicals but many of the minor ones. They discuss possibilities for why this would be. I'm no chemist so don't know what limitations on assaying these things there are but stomach contents may vary seasonally so the toxin sources may only be available during certain times of the year. Or, who knows how frequently they have to ingest one or more of these sources to maintain toxin levels? It's possible that just on probability the toxin sources are present in the gut only a small percentage of time. There is still a lot to learn but the evidence for a dietary source is strong. It also looks like for the most part the frog is a storage organ rather than a chemical modification factory but to what extent this holds true, who knows?

I would like to add one thing about the Pithuoi story. There is an element of ethnobiology here. The beetle was well known by the local natives and they also knew it was what made the birds poisonous. Their name for the beetle was something like burning eye beetle or similar.


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## steelcube (Mar 17, 2004)

ED's_Fly_Meat_Inc said:


> The topic was batrachotoxins in dart frogs. I argued that it was diet related and she argued that it could be a catacholamine response. I.E. Fight or flight induced. Her hypothesis is that these frogs produce toxins in the wild due to their constant fight for survival, and that the reason they lose their toxicity in captivity is because of the lack of predators in captivity. The constant fight for survival is gone, so the ability to produce toxins is atrophied. In the professional breeders series there is a great chapter on batrachotoxins and there is mention of terriblis being toxic for months (it may be years) after captivity. I agrued that dart toxins vary seasonally, and her reply was that so do predators. Ergo various catacholomine responses would vary.


If the ability to produce toxins is atrophied, CB frogs won't be able to produce toxins after being release back into the wild... 

a definite answer would be to set a greenhouse cage for a CB frog/s in the middle of a rainforest that lets insects in. Then someone can measure toxin contents after a period of time.


SB


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## Marty (Feb 27, 2004)

*Re: Wow*

Erin, I sent you a PDF of that article by John Daly. Very good read. 

if anyone else wants it email me and I'll send it to you.

article has been published in PNAS so I don't want to post it here.

M.



ED's_Fly_Meat_Inc said:


> Great replies. Very interesting.
> 
> I was a little thrown back by the Pithuoi bird discovery. It sounds like they did find the source for the bird. But that bird is in New Guinea. The same family of beetle is in the Columbian area, but is it toxic? Also, it's not the same beetle. And I have not seen many darts munch down an adult beetle. Let alone a bunch. It is a stretch, and the authis of most of the articles admit this. But, it may indeed explain why the Phyllobates are toxic, but what about the histrotoxins, and pumiliotoxins of the these respective frogs. I am not buying a pumilio chowing down on Melyrid-like beetles. No way.
> 
> ...


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## EDs Fly Meat (Apr 29, 2004)

*Wow*

Now that is interesting Brent,

Pumiliotoxins were found in the arthropods and the variations in the chemicals found matched the pumiliotoxins of the frogs in those same locations. Not only is it strong evidence the toxins are derived from food, it also suggests the toxins are simply sequestered unmodified.



> As for the melyrid beetles. They are tiny and could easily be consumed in quantity by frogs. I sent the PNAS paper to an entomologist friend when it came out and he said these beetles are varied (lots of species) and widespread but the interesting thing is that the have strange pustules that nobody has figure out what they are for.


I did not know that. And it may prove to be true, but even with your experience what are your thoughts on darts and beetle consumption? imposible, possible, probable, factual? I have seen tinctorius group frogs eat adult rice flour beeles. Not their favorite, and most reject them. But Ihave some customers who swear that theirs love them. I just question it based on a few things. The beetles are tiny and hard (I am purely speculating for fun mind you) why bother? One of my favorite ecology stories is about a species of crab that eats mussels. Now these crabs don't eat the big mussels because they spend too much energy having to break them up in order to eat them. They don't eat the small ones either as is takes to much energy gathering them for a meal. But the select out the ones who "are just right" they feel and measure, and test them and then go for it. Would a frog do the same with a small, hard beetle? I don't know, but given a choice one would think that it would go for a easier to digest, softer, yummier food item like a fly or a juicy spider.



> The problem with getting the proof or doing stomach analysis on terribilis is that the area of Colombia where they live is unstable and dangerous. Only scientists who don't mind being kidnapped dare tread there.


Let us hope Justin will be okay there in June.



> I'm no chemist so don't know what limitations on assaying these things there are but stomach contents may vary seasonally so the toxin sources may only be available during certain times of the year.


There is a facinating chapter in the professional breeders series book on batrachotoxins. Daly did some gas chromatography on batrachotoxins and found the toxins of terriblis to be distinctly different from another frog lugubris I think. It was an exciting discovery because at teh time the thought was, "Wow here is a way to possibly ID a frog from an unknown morph." However, what he found out was that as the diet changes throughout the year so do the gas chromatography spectrums. So from season to season the same population of frogs change in the expression fo their toxins. This I found very cool. A strong argument for diet. My friend Gretchen argues that if toxins are catacholamine induced, the changes can be explained by the type of seasonal predators seeking out the frogs. I'll have to pick up that paper again.

Steve B had a really interesting point.


> a definite answer would be to set a greenhouse cage for a CB frog/s in the middle of a rainforest that lets insects in. Then someone can measure toxin contents after a period of time.


That would be an interesting paper.

Going back to an earlier point Brent.
[/quote]Pumiliotoxins were found in the arthropods and the variations in the chemicals found matched the pumiliotoxins of the frogs in those same locations. Not only is it strong evidence the toxins are derived from food, it also suggests the toxins are simply sequestered unmodified.


> I am less of a chemist than you are, and in all likelyhood you are dead on. But, I still think that it is possible that these toxins are easily torn down and created. Working in a healthcare setting I see the occasional antibiotic resistant bacteria. Vanomycin Resistant Enterococcus (VRE) is a scary one. This bacteria has mutated so that it not only is it resistant to Vanco, it has genes that make protiens so that it can eat the stuff. It makes proteins that cleave up the vanco molecules into smaller molecules so that it can build kreb cycle intermediates, or cheap sugars. :shock: There is a bacteria that does the same to agent orange. True the toxins go into the frogs as one thing, but they don't come out the same way. They look similar and have traits of the original but come out with all these funky branches and hydrogens stuck on them. So while you are probably right, I ask if it is possible that these molecules could be torn down and recombined?
> 
> I am enjoying the replies a great deal. Thanks for the input on the topic.
> Dave


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## bbrock (May 20, 2004)

*Re: Wow*



ED's_Fly_Meat_Inc said:


> I did not know that. And it may prove to be true, but even with your experience what are your thoughts on darts and beetle consumption? imposible, possible, probable, factual?


Without a doubt factual. I think flour beetles probably don't taste great because I have seen many frogs do the tongue drag on them. Others eat them but not with relish. However, if you watch what they do with the tiny beetles that come out of meadow plankton.... they snap them up by the dozens. Also, ants are also small and hard - a very poor nutrition substance. But I think the frogs are pretty simple about food. For the most part I think they just think "Oh, there is something that is small and moves, I'll try to eat it" If it doesn't taste bad, they eat more.




> Let us hope Justin will be okay there in June.


I have heard that the siuation has improved. Justin sounded like they had done their homework and knew what to do. I believe they have an indiginous guardian who would be with them at all times.



> I am less of a chemist than you are, and in all likelyhood you are dead on. But, I still think that it is possible that these toxins are easily torn down and created.


Do not underestimate my stupidity in chemistry. I really could not anser this. It sounds plausible to me.


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## bbrock (May 20, 2004)

*Re: But...*



ED's_Fly_Meat_Inc said:


> Why would they not be eaten? If a predator ate one and lived it learned a vaulable lesson. I.E. "avoid the chubby, orange ones." If it ate one and died? Well, what would keep the frog from evolving and continuing to make toxins?
> 
> Your thoughts?
> Dave


This is one of the interesting aspects of the whole deal. The toxins in terribilis are almost always lethal - try to eat one and you die, end of story. Only a couple of predators have been known to eat a terribilis and survive.


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## EDs Fly Meat (Apr 29, 2004)

*Ric*

With all due respect to Ric, I just don't follow his logic.

quote]The idea that the toxins are a result of 'the struggle to survive' is illogical, all scientific knowledge aside. If toxins were being produced from the stress caused by constant risk of predation, then the frogs would be toxic as hell, so they would not be eaten. Thus they would have no stimulus to produce toxins.[/quote]

Why is it illogical to think that predators would attempt, again and again to eat something that killed them. Take a tarantula for example. It makes an attempt on a terriblis and it dies. But there are thousands of spiders and snakes, and insects, and such that would contstantly pressure this frog to defend itself through our proposed cholinergic response. Not every attempt would be successful, and not every attempt would cause the death of the frog or the predator. So how would they lose the stimulus to produce toxins this way?
Dave


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## bbrock (May 20, 2004)

*Re: Wow*



ED's_Fly_Meat_Inc said:


> My friend Gretchen argues that if toxins are catacholamine induced, the changes can be explained by the type of seasonal predators seeking out the frogs.


Nah, sorry. This suggests that the toxin profile in the skin is being tailored to match specific predators. That's not what's being seen and it also wouldn't make sense. The toxins in the skin apparently remain relatively stable but the availability of the sources my vary seasonally. It was the chemicals in the arthropod cocktail that lacked some of the major alkaloids always present in the frog skins tested. Besides that, the toxin profiles seem to be perfectly capabably of detering a wide range (virtually all) predators. Why have a complex and evolutionarily (probably energeticly) expensive mechanism to produce all these custom toxins when one nasty cocktail seems to work fine?

One other point that may have been mentioned early is that we can beat the hell out of these frogs in captivity and still not get the major toxins out of them. If the source is not dietary, why would this be?


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## bbrock (May 20, 2004)

steelcube said:


> If the ability to produce toxins is atrophied, CB frogs won't be able to produce toxins after being release back into the wild...
> 
> a definite answer would be to set a greenhouse cage for a CB frog/s in the middle of a rainforest that lets insects in. Then someone can measure toxin contents after a period of time.
> 
> ...


As usual, great point. I think the experiment has already been done although I 've never tracked down the citation. As I understand it (all second hand) Hawaiian auratus were assayed and found to have a different toxin profile than their parent population on Taboga Island. If I remember right, some HI auratus were reared indoors and lost toxins but those reared in screen cages outdoors with access to local insects produced toxins. Read this with skepticism since I haven't read the paper myself but if anyone has that citation, I would be interested.


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## EDs Fly Meat (Apr 29, 2004)

> Read this with skepticism since I haven't read the paper myself but if anyone has that citation, I would be interested.


As would I brent.



> Nah, sorry. This suggests that the toxin profile in the skin is being tailored to match specific predators. That's not what's being seen and it also wouldn't make sense. The toxins in the skin apparently remain relatively stable but the availability of the sources my vary seasonally. It was the chemicals in the arthropod cocktail that lacked some of the major alkaloids always present in the frog skins tested. Besides that, the toxin profiles seem to be perfectly capabably of detering a wide range (virtually all) predators. Why have a complex and evolutionarily (probably energeticly) expensive mechanism to produce all these custom toxins when one nasty cocktail seems to work fine?


I agree with you. I am curious what Gretchen has to say about this. Although I strongly suspect she'll want documentation.
Dave


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## Ed (Sep 19, 2004)

Here is a short list of the articles that I could pull together. I think the first one is the one that shows the loss of toxicity based on the food source. 


Daly, John W., Sherrie I. Secunda, H. Martin Garraffo, Thomas F. Spande, Anthony Wisnieski and Jack F. Cover, Jr. 1994. An uptake system for dietary alkaloids in poison frogs (Dendrobatidae). Toxicon. 32 (6):657-663. colostethus dendrobates phyllobates epipedobates 

Daly, J. W., T. F. Spande, N. Whittaker, R. J. Highet, D. Feigl, N. Nishimori, T. Tokuyama and C. W. Myers. 1986. Alkaloids from dendrobatid frogs: Structures of two w-Hydroxy congeners of 3-butyl-5-propylindolizidine and occurrence of 2,6-disubstituted piperidine. Journal of Natural Products. 49 (2):265-280. poison frog, Dendrobates histrionicus, Amphibia, Anura, Colombia, histrionicotoxins, defense, toxicity, skin secretions 

Daly, J., W., C.W.Myers and N. Whittaker. 1987. Further classification of skin alkaloids from Neotropical poison frogs (Dendrobates) with a general survey of toxic/noxious substances in the Amphibia. Toxicon. 

Edwards, M. W., J. W. Daly and C. W. Myers. 1988. Alkaloids from a Panamanian poison frog, Dendrobates speciosus: Identification of pumiliotoxin-A and allopumiliotoxin class alkaloids, 3, 5-disubstituted indolizidines, 5-substituted 8-methylindolizidines, and a 2-methyl-6-nonyl-4-hydroxypiperidine. Journal of Natural Products. 51 (6):1188-1197. Dendrobatidae, toxins, Amphibia, Anura 

Edwards, M. W. and J. W. Daly. 1988. Alkaloids from a Panamanian poison frog, Dendrobates speciosus: Identification of pumiliotoxin-A and allopumiliotoxin class alkaloids, 3,5-disustituted indolizidines, 5-substituted 8-methylindolizidines, and a -methyl-6-nonyl-4-hydroxypiperidine. Journal of Natural Products. 51 (6):1188-1197. Amphibians, frogs, Dendrobatids, toxins, skin secretions, Panama, alkaloids 

Edwards, M. W. and John W. Daly. 1988. Alkaloids from a Panamanian poison frog, Dendrobates speciosus: identification of Pumilotoxin-A and allopumiliotoxin class alkaloids, 3, 5-disubstituted inolizidines, 5-substituted 8-methylinolizidines, and a 2-methyl-6-nonyl-4-hydroxypiperidine. Journal of Natural Products. 51 (6):1188-1197. 

Tokuyama, T., J. W. Daly, H. M. Garraffo and T. F. Spande. 1992. Pyrrolizidine oximes: A novel new class of dendrobatid alkaloids. Tetrahedron. 48 (21):4247-4258. toxins, Amphibia, Anura, Dendrobatidae, Dendrobates pumilio 

Hutchinson, Kira, James V. Silverton and John W. Daly. 1994. Synthesis of pyrrolizidine oximes 222 and 236: Novel alkaloids of a dendrobatid poison frog. Tetrahedron. 50 (21):6129-6136. Dendrobates pumilio, Polyzonium rosalbum 
Daly, John W. and H. Martin Garraffo. 1997. Highly selective construction of trans(2,3)-cis(2,6)-trisubstituted piperidines: An application to the chiral synthesis of Dendrobates alkaloids. Tetrahedron. 53 (28):9553-9574. 

Daly, John W., H. Martin Garrafo and Charles W. Myers. 1997. The origin of frog alkaloids: An enigma. Pharmaceutical News. 4 (4):9-14. Melanophryniscus, Mantella, Pseudophryne, Epidobates, Phyllobates, Dendrobates, histrionicus, auratus 

Garraffo, H. M., P. Jain, T. F. Spande and J. W. Daly. 1997. Alkaloid 223A: The first trisubstituted indolizidine from dendrobatid frogs. J. Nat. Prod. 60 2-5. Dendrobates pumilio, Dendrobatidae 


Ed


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## ETwomey (Jul 22, 2004)

*Re: Ric*



> Why is it illogical to think that predators would attempt, again and again to eat something that killed them. Take a tarantula for example. It makes an attempt on a terriblis and it dies. But there are thousands of spiders and snakes, and insects, and such that would contstantly pressure this frog to defend itself through our proposed cholinergic response. Not every attempt would be successful, and not every attempt would cause the death of the frog or the predator. So how would they lose the stimulus to produce toxins this way?


This is a very good point. It is true that individuals of a toxic species would still be targeted by naive predators. However, take for instance an aposematic, toxic species (i.e. terribilis) that is somewhat abundant. While certain individuals might be harrassed by predators due to chance, many other individuals would be 'protected' from the misfortunes of their conspecifics. I think predation attempts would be drastically lower in terribilis than in, say, a Colostethus. Over evolutionary time you would probably observe some sort of innate avoidance by predators of bright yellow frogs, especially if failure to avoid these frogs results in death. So yes, in any given generation you would still see some frogs that were targeted, but the species as a whole might be given some protection by being aposematic. Please forgive my longwinded and convoluted argument!

-Evan


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## mydumname (Dec 24, 2004)

Isn't the terribilis toxin strong enough to basically kill an animal almost instantly? If so, how would an animal know not to go after these frogs? One try, and they are done, no second chances, right? Many toxic animals are brightly colored, which is another type of defense. Animals that aren't toxic are usually duller in color so they can hide, but of course you have the bright ones that use their bright colors to "appear" toxic. Somehow predators know not to go after these animals (now I am sure some still do). Could this just be another display of animal instincts? It is not a learned behavior because how would these animals teach another animal? This may be slightly off topic but I feel it shows another example of instinc versus learned behavior.


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## Ed (Sep 19, 2004)

snip "but even with your experience what are your thoughts on darts and beetle consumption? imposible, possible, probable, factual? I have seen tinctorius group frogs "

There is indication that at least in reptiles, that it is the species of prey, not the size of the prey is an important selector for predation. This is also seen in some lizards that will consume soil or other calcium rich material as needed to provide sufficient calcium to meet metabolic needs. 
In addition, given that at least in caudates, there is an ability to discriminate between calorically rich prey items and calorically poorer prey items, I would not be surprised to see that there is a preference to consume those insects when available. 

Ed


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## steelcube (Mar 17, 2004)

The evolution theory would say that the ones survived are those that have "timid of bright colored animals" trait. Some animals have, other don't. The ones that have... breed, the other don't.

However... I don't really believe that.  I think there is a mechanism that "saved" "some environmental influences" (learned behaviour included) into genes and pass onto the next generation (for many higher, more complex animals) 

Of course, many scholars would disagree with this... but since we all agree to write our own theories about it... that's mine.


SB


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## EDs Fly Meat (Apr 29, 2004)

Now that is a good point.



> In addition, given that at least in caudates, there is an ability to discriminate between calorically rich prey items and calorically poorer prey items, I would not be surprised to see that there is a preference to consume those insects when available.


Did Steve Waldron talk about this in his pumilio observations? I am so curious to see know about their feeding habits in the wild. Justin Yeager mentioned observing pumilio eating mites in the wild. How small is that food item?

Dave


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## Ed (Sep 19, 2004)

Very small. 
I think this is the reference you want 

Simon, M. P. and C. A. Toft. 1991. Diet specialization in small vertebrates: Mite eating in frogs. Oikos. 61 263-278. Amphibia, Anura, invertebrates, morphology, taxonomy, ecology, mites, prey, feeding 


Ed


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## Cory (Jan 18, 2005)

If we go back to the evolution of the PDF's, there has to be some starting point for their toxicity. Making an assumption that they evolved out of similiar species as other harmless frogs there would have had to have been some defining characteristic of their environment that would change them relative to other evolving species. One key thing that changes rapidly throughout different ecological niches are the food prey. So if this frog eats a toxic insect and is able to not only survive but enjoys the food source they would benefit from the toxins now in their system. As the process continues the frogs would probably become more and more bold as predatory pressure is reduced. The more colored species would live longer because of pattern recognition by predators until you get the PDF of today. Of course until the experiment is done and the right insects are found this will never be proven.

I have seen research that the color yellow illicits a flight or fight response in mammals. This is one of the reasons school buses are yellow.

I would find it hard to believe that pdf's are capable of synthesizing the toxins, because of their lack of toxicity in captivity.

As far as secretion of toxins, that is a definate issue for autopsy to discover, but expensive because it is soley for the sake of science.


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## bbrock (May 20, 2004)

ED's_Fly_Meat_Inc said:


> I agree with you. I am curious what Gretchen has to say about this. Although I strongly suspect she'll want documentation.
> Dave


Which part would she want documentation for, that the toxins are affective against a wide range of predators or the logical thought process behind my argument. If it is the former, the numerous Daly pubs should work, if it is the latter, then:

Brock, B.L. 2005. Things I say on dendroboard. Journal of My Butt 1:1

But seriously, if a frogs toxins changed seasonally in response to different predators, then I would be interested to hear and alternative to the idea they would be tailoring toxins to fit the predator.


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## EDs Fly Meat (Apr 29, 2004)

Ed you are a rock star! Thanks!  



> I think this is the reference you want
> 
> Simon, M. P. and C. A. Toft. 1991. Diet specialization in small vertebrates: Mite eating in frogs. Oikos. 61 263-278. Amphibia, Anura, invertebrates, morphology, taxonomy, ecology, mites, prey, feeding





> Brock, B.L. 2005. Things I say on dendroboard. Journal of My Butt 1:1


Well not as scientific as Ed's reference but worth its merit nonetheless. You are too funny. I laughed out loud when I read that. Gretchen's original hypothesis is; why can't we rule out toxin release as a fight or flight reaction? Is there a paper on that? And if not, until proven otherwise despite the overwhelming data that points to diet (thanks again Ed), should it not be considered?
Dave


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## bbrock (May 20, 2004)

ED's_Fly_Meat_Inc said:


> Well not as scientific as Ed's reference but worth its merit nonetheless. You are too funny. I laughed out loud when I read that. Gretchen's original hypothesis is; why can't we rule out toxin release as a fight or flight reaction? Is there a paper on that? And if not, until proven otherwise despite the overwhelming data that points to diet (thanks again Ed), should it not be considered?
> Dave


What do you mean not as scientific? It's a VERY prestigious journal with a very high rejection rate. So far, only one author has actually made it past peer review. Boy! Some people! ;-)

Let's just say I would have a hard time recommending this fight or flight proposal for funding. The idea in itself is fine and there are examples of toxic animals, even anurans, that secret their toxins in response to a predator. I don't know of any that actually manufacture the toxin on the spot though. But the really troubling problem is that if this were the mechanism, why can't it be induced in laboratory conditions. To suggest that the stimulus is to a specific predator is... well... WAY beyond any evolutionary adaption I'm aware of. Remember the engineering adage "keep it simple". It applies to adaptation too. By far the most evolutionarily simple and also robust adaptation would be to have one set of toxins and delivery system that works well for as many predators as possible. This argues for a generalized secretion response where anything that appears to be predation, should trigger secretion.

So... getting back to the original argument. Absent the body of literature I would say no, you can't rule out the fight or flight reaction. But it would be absolutely amazing to me if the response weren't exhibited under lab conditions if this were the case for the reasons I stated above (do you need another citation?). In addition, I think the literature has pretty much zeroed in on a dietary source but in the beginning, all bets were open as to what the source and release mechanisms were so it's important to remember that 30 some years ago young grad students and mentors were probably sitting around the bar having this same discussion which guided the research in the coming years. 

A very interesting discussion and these kinds of things are great because the force you to step back and make sure all the pieces fit together properly. Thanks Dave, as you know, I'm in need of a little stimulating conversation lately.


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## Ed (Sep 19, 2004)

snip "Which part would she want documentation for, that the toxins are affective against a wide range of predators" 

Refer her to 
Erspamer, Vittorio; 1994; Bioactive Secretions of the Amphibian Integument; In Amphibian Biology, The Integument eds Heatwole, H.; Surrey Beatty and Sons; Australia (especially pages 293-297 for the batrachotoxins). 

You can pass this along from the toxicology section snip "It was estimated that the humans lethal dose would be less that 300 ug, the contents of a third of a skin of terriblis (Daley and Witkop, 1971). Death is mainly attributable to induced cardiac arhythmias, ventricular fibrillation and cardiac arrest." 

There are paragraphs describing the dose dendent effects on multiple different tissues in multiple animals. Batrachotoxins are pretty nondiscriminatory in effect.........

snip " I read that. Gretchen's original hypothesis is; why can't we rule out toxin release as a fight or flight reaction? Is there a paper on that? And if not, until proven otherwise" 

In the literature and in anecdotal reports, there is strong evidence that that the there is also a significant percentage of the toxins as well as other chemical compounds present on the skins of amphibians (see the well documented examples of toxins in skin secretions of pickeral frogs (Rana palustris) killing other anurans housed with them for one example). This is only one example out of a huge body of literature that is not confined soley to Dendrobatids. However as their are also granular skin glands containing the toxins, the frogs should be able to secrete more if needed. (I wish I could remember the researcher's name but he had a small battery powered device that was originally developed to cause the glands to empty for sample collection). 


Ed


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## andersonii85 (Feb 8, 2004)

Here are some more useful articles:

Toft, C. A. Feeding Ecology of Panamanian Litter Anurans: Patterns in Diet and Foraging Mode. 1981. Journal of Herpetology 15 (2): 139-144

Summers, K., Clough, M. E. The Evolution of coloration and toxicity in the poison frog family (Dendrobatidae). 2001. Evolution 98 (11): 6227-6232

Daly, J. W., et al. Bioactive alkaloids of frog skin: Combinatorial bioprospecting reveals that pumiliotoxins have an arthropod source. 2002. Proceedings of the National Academy of Science October 29; 99 (22): 13996-14001

These are some really good articles for the discussion. I will weigh in on this discussion soon. I need some time to think. 

Best,

Justin


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## EDs Fly Meat (Apr 29, 2004)

*Artcles*

Well Thanks to Ed I have some reading material for the next few days. He posted this article, and I have to ask others interested in this topic to read it as well, its great.

Daly, John W., Sherrie I. Secunda, H. Martin Garraffo, Thomas F. Spande, Anthony Wisnieski and Jack F. Cover, Jr. 1994. An uptake system for dietary alkaloids in poison frogs (Dendrobatidae). Toxicon. 32 (6):657-663. colostethus dendrobates phyllobates epipedobates


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