[EDs Fly Meat]

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.

 

[Guest]

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.

 

[EDs Fly Meat]

Well

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

 

[Ben_C]

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

 

[Guest]

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?

 

[EDs Fly Meat]

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

 

[Will]

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.

 

[Darren Meyer]

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

 

[EDs Fly Meat]

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.

 

[dmartin72]

Maybe Gretchen is the MD.

 

[mindcrash]

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

 

[bbrock]

/


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.

 

[mydumname]

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.

 

[Blort]

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.

 

[bbrock]

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.

 

[ETwomey]

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!

 

[Guest]

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

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.

 

[Ed]

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

 

[bbrock]

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!

 

[bbrock]

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!