# Can dart frogs regain their poison?



## NateDawg (Oct 16, 2020)

Okay so I believe that, in the wild, a dart frog gets its poison from eating insects that ingest poisonous plants? In captivity, a dart frog will not carry those poisons because there are not those specific insects to get the poison from? I was at my LRS the other day talking about various frog related things and he had mentioned something about some frogs possibly still being able to have poisons in there skin even if they were captive breed? Has anyone heard of this or have a link to an article? Now obviously there are a great number of various dart species and they dont all carry the same poisons either so that can play a major factor for my question.


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## Socratic Monologue (Apr 7, 2018)

Some (most?) frogs (non-Dendrobatids) synthesize their own toxins; those species can be/are toxic in captivity. Dendrobatids (i.e. dart frogs) sequester their toxins from prey, so unless the dart frogs eat the toxin-containing prey, those dart frogs are not toxic.

It may be an open question (or unknown to me) whether some darts can sequester some toxins from prey species that we have access to in captive husbandry (e.g. North American formicine ants, spiders).


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## NateDawg (Oct 16, 2020)

Socratic Monologue said:


> Some (most?) frogs (non-Dendrobatids) synthesize their own toxins; those species can be/are toxic in captivity. Dendrobatids (i.e. dart frogs) sequester their toxins from prey, so unless the dart frogs eat the toxin-containing prey, those dart frogs are not toxic.
> 
> It may be an open question (or unknown to me) whether some darts can sequester some toxins from prey species that we have access to in captive husbandry (e.g. North American formicine ants, spiders).


Okay thanks, that makes sense.


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## minorhero (Apr 24, 2020)

There is a guy on facebook that keeps santa isabel frogs in a greenhouse. They free roam in the green house and eat a variety of bugs. About 2 months or so back he posted a picture of his arm where he had a good sized rash. He said his santa isabel had landed on his arm when he was doing some work in the green house. Shortly after it landed it hoped on its way. From memory he said he felt a bit sick afterwards and then noticed the rash but had since recovered. His frogs were all captive bred, many of them being born and raised in that greenhouse. So its definitely possible if they eat the right things and possible with insects from north america. What insects? No idea. Frankly I'm glad its difficult to accomplish since if dart frogs were regularly dangerous I just straight up wouldn't own any.


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## NateDawg (Oct 16, 2020)

minorhero said:


> There is a guy on facebook that keeps santa isabel frogs in a greenhouse. They free roam in the green house and eat a variety of bugs. About 2 months or so back he posted a picture of his arm where he had a good sized rash. He said his santa isabel had landed on his arm when he was doing some work in the green house. Shortly after it landed it hoped on its way. From memory he said he felt a bit sick afterwards and then noticed the rash but had since recovered. His frogs were all captive bred, many of them being born and raised in that greenhouse. So its definitely possible if they eat the right things and possible with insects from north america. What insects? No idea. Frankly I'm glad its difficult to accomplish since if dart frogs were regularly dangerous I just straight up wouldn't own any.


Interesting, so I wonder if these frogs are able to "collect" a much larger variance of poisons than just the few that I read about in some articles.


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## Louis (Apr 23, 2014)

I think millipedes would also be a risk factor for this as well as ants. But the diversity of insect fauna in a greenhouse that it's probably safe to assume isn't exposed to pesticides if it contains dart frogs would make it really difficult to identify exactly where the frogs where concentrating toxins from.
do you have a link to this guys page? I'm reallt curious to see the greenhouse.


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## Socratic Monologue (Apr 7, 2018)

minorhero said:


> So its definitely possible if they eat the right things and possible with insects from north america.


FWIW, I doubt it likely that only native North American species of insects inhabit a greenhouse. That sort of housing might border on 'non-captivity' for the purposes of some discussions. Interesting case.


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## Louis (Apr 23, 2014)

Socratic Monologue said:


> FWIW, I doubt it likely that only native North American species of insects inhabit a greenhouse. That sort of housing might border on 'non-captivity' for the purposes of some discussions. Interesting case.


One example of exactly this that I know of is that the dwarf white woodlouse Trichorhina tomentosa has become 'naturalised' to the UK but is generally restricted to greenhouses because of the climate.
The glasshouses at the royal botanic gardens in Edinburgh have all sorts of interesting non native insects present that arrived on plants, not least of which are cockroaches. Several years ago a particularly large tree fern had to have its crown chopped off and it displaced hundreds and hundreds of exotic cockroaches that rained down on observers below.
Only tangentally related but they have a breeding colony of free roaming water dragons in one of the greenhouses at Kew gardens too. There is at least one species of treefrog breeding in the glasshouses in Edinburgh and in Glasgow they are known to host various released exotic pets, some of which have managed to thrive. Unfortunately they have more terrapins than they know what to do with living in the glasshouses which are closed to the public.


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## Schledog (Apr 28, 2020)

Are the auratus on Hawaii poisonous? They aren't captive but Im curious if they can gain poison from other insects.


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## macg (Apr 19, 2018)

Schledog said:


> Are the auratus on Hawaii poisonous? They aren't captive but Im curious if they can gain poison from other insects.


Yes, there was someone asking for help on this forum after their cat put an auratus in it's mouth in Hawaii. The cat was having serious problems immediately after the encounter.


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## macg (Apr 19, 2018)

Questions about poison levels in Hawaiian Auratus...


So, I live in Hawaii, specifically the back of Manoa Valley. There is a huge breeding ground for the green and black dart frogs just up the hill. We have seen a few frogs more recently, and one or two have been living under our house. We have 3 outdoor cats. Today the smallest of our cats...




www.dendroboard.com





The thread


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## Johanovich (Jan 23, 2017)

minorhero said:


> There is a guy on facebook that keeps santa isabel frogs in a greenhouse. They free roam in the green house and eat a variety of bugs. About 2 months or so back he posted a picture of his arm where he had a good sized rash. He said his santa isabel had landed on his arm when he was doing some work in the green house. Shortly after it landed it hoped on its way. From memory he said he felt a bit sick afterwards and then noticed the rash but had since recovered. His frogs were all captive bred, many of them being born and raised in that greenhouse. So its definitely possible if they eat the right things and possible with insects from north america. What insects? No idea. Frankly I'm glad its difficult to accomplish since if dart frogs were regularly dangerous I just straight up wouldn't own any.





Socratic Monologue said:


> FWIW, I doubt it likely that only native North American species of insects inhabit a greenhouse. That sort of housing might border on 'non-captivity' for the purposes of some discussions. Interesting case.


Not sure if this is the same guy, but I know Mark Anders is keeping E. anthonyi in his greenhouse. He is located in the UK. I haven't seen the rash post though so could be someone else.


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## Socratic Monologue (Apr 7, 2018)

This might be worth a read:



https://pdfs.semanticscholar.org/6067/6a68a75c4fa4768535c799eb288e76225cbc.pdf



Excerpt: 
"The purpose of this paper is to provide a brief review of the ideas and research that ultimately led to the discovery that poison frogs sequester most of their lipophilic alkaloids from dietary arthropods, an idea that became known as the ‘dietary hypothesis’ ."

The key word here is "most". Possibly (likely?) some compounds are synthesized, though maybe not the really interesting (i.e. toxic) ones.

Regarding the cat case: I'm not convinced by the implication that a foamy mouth outdoor cat with a frog nearby is a smoking gun that Hawaiian darts are toxic. If the frog was alive/uninjured, this is strong evidence that the frog was never in the mouth of the cat. A recently attacked frog could be expected to be hiding, too; if the frog was easily found, that is evidence that the frog isn't part of this. If the frog was chewed on and merely tasted terrible, that would cause the reaction. If the cat chewed on something else (insect? plant?) a frog could well be nearby. If the cat chewed on another known toxic species of frog, there might well be other frog species nearby -- there are more than one species of invasive _Bufo_ living in high densities in Manoa Valley.

Other than the fact that people expect dart frogs to be toxic, and are frightened by this thought, there isn't good evidence here.


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## Woodswalker (Dec 26, 2014)

I wasn't going to say anything because I have concerns about what people do with information like this, but since it's already being discussed:









Melyrid beetles (Choresine): A putative source for the batrachotoxin alkaloids found in poison-dart frogs and toxic passerine birds


Batrachotoxins are neurotoxic steroidal alkaloids first isolated from a Colombian poison-dart frog and later found in certain passerine birds of New Guinea. Neither vertebrate group is thought to produce the toxins de novo , but instead they likely sequester them from dietary sources. Here we...




www.pnas.org





This is why I question the wisdom of feeding certain insects, like beetles, considering the trend towards biotopes, which could mean inadvertently selecting the very plant species that produce the alkaloids responsible for toxin development. There are some plants in the hobby that definitely produce toxic alkaloids. I'd like to think that the beetles currently available as feeders were chosen because they don't chew live plants, and are therefore unlikely to present a risk, but I have always been leery of feeding beetles, and this is my primary reason why. Recently, I finally broke down and bought some, but I'm still not sure I want to use them. Furthermore, I reeeeeally don't want them getting into my dry goods. Even if I'm only feeding off larvae, how many will be missed and end up developing into adult beetles? How many will escape?


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## Woodswalker (Dec 26, 2014)

Another relevant article, this one discussing the aforementioned formicine ants:









Formicine ants: An arthropod source for the pumiliotoxin alkaloids of dendrobatid poison frogs


A remarkable diversity of bioactive lipophilic alkaloids is present in the skin of poison frogs and toads worldwide. Originally discovered in neotropical dendrobatid frogs, these alkaloids are now known from mantellid frogs of Madagascar, certain myobatrachid frogs of Australia, and certain...




www.pnas.org


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## DPfarr (Nov 24, 2017)

I would side on the complex metabolic chain needed from plant 2° compounds to plants predator to frog being the process.


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## Johanovich (Jan 23, 2017)

Woodswalker said:


> I wasn't going to say anything because I have concerns about what people do with information like this, but since it's already being discussed:
> 
> 
> 
> ...


The current beetles for feeding were definitely not selected because they don't chew on live plants. Wheat weevils will happily munch on live plants. Most feeder insects were selected solely because they are easy to breed (which often means they are potential pest species as well).

I was under the impression that ants, mites and millipedes were considered to be the primary sources for dart frog poison, but apparently some beetles are also responsible: Dietary source for skin alkaloids of poison frogs (Dendrobatidae)?


Btw there is also a study that deliberately dusted fruit flies with alkaloids to see if Melanophryniscus stelzneri would become toxic again. Short answer was yes:








Dietary alkaloid sequestration in a poison frog: an experimental test of alkaloid uptake in Melanophryniscus stelzneri (Bufonidae) - PubMed


Several lineages of brightly colored anurans independently evolved the ability to secrete alkaloid-containing defensive chemicals from granular glands in the skin. These species, collectively referred to as 'poison frogs,' form a polyphyletic assemblage that includes some species of...




pubmed.ncbi.nlm.nih.gov





And a similar older study on Dendrobates, Epipedobates and Phyllobates:








An uptake system for dietary alkaloids in poison frogs (Dendrobatidae)


The skin of poison frogs (Dendrobatidae) contains a wide variety of alkaloids that presumably serve a defensive role. These alkaloids persist for year…




www.sciencedirect.com


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## Woodswalker (Dec 26, 2014)

Maybe I needed to spell it out more clearly.

If we're stocking our tanks with the plants that contain the right alkaloids, and also feeding insects that will then munch on these plants and subsequently be consumed by our frogs, then we are recreating the chain that leads to toxicity.

Edit: This is why I am saying that expecting beetles not to eat plants is only wishful thinking, and why I have questioned the practice of feeding them at all.


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## Peregrin1 (Apr 28, 2020)

At my daughters University, the biology department keeps/works with Darts. They have "toxic" and non toxic frogs. The professor wouldn't get specific, but I was led to believe that they simply dust the food for the toxic ones with "something".


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## Johanovich (Jan 23, 2017)

Woodswalker said:


> Maybe I needed to spell it out more clearly.
> 
> If we're stocking our tanks with the plants that contain the right alkaloids, and also feeding insects that will then munch on these plants and subsequently be consumed by our frogs, then we are recreating the chain that leads to toxicity.
> 
> Edit: This is why I am saying that expecting beetles not to eat plants is only wishful thinking, and why I have questioned the practice of feeding them at all.


Not necessarily, the beetles we feed still have a very different metabolism compared to the beetles they consume in the wild. Even if we stock our tanks with the correct plants (which I'm not even sure is possible), the beetles need to feed enough of those plants or their leaf litter to get a significant dose of alkaloids inside of them and that dose also needs to stay inside the beetle (not being broken down or something similar). Also, considering those alkaloids serve to deter herbivory, the beetles might even start to avoid those plants after a few bites.

It's also important to note that the alkaloids present in mites (which are still believed to be a major contributor to frog toxicity) are produced by the mites themselves and not absorbed through their diet. Similarly some of the ants that are believed to be a potential source of pumiliotoxins either produce alkaloids themselves or putatively have symbiotic bacteria in them that produce them. There is a suggestion for transfer of alkaloids from plants to aphids and beetles (with some of the ant species perhaps getting alkaloids from tending aphids), but I could not find much info on this, specifically on the type of alkaloids and if/how they are changed by the intermediate hosts (aphids, beetles and ants). I'm not even sure there are plants that have similar alkaloids to the ones found in frogs (such as pumiliotoxins), but I would be happy to be proven wrong.


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## NateDawg (Oct 16, 2020)

Okay so from all the research I'm seeing that there hasn't been a dart frog recorded to be able to produce it's own toxin, it must get the toxin from food intake. And to be even safer, the plants that are used inside the viv should be void of producing particular toxins that could be eaten by various insects?


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## Socratic Monologue (Apr 7, 2018)

I hope you're not overthinking this. Many (most?) frogs kept in captivity are toxic; some amphibians (Eastern Newts, for one) can and have caused documented human fatalities. In other hobbies such as reef tank keeping, many thousands of keepers care for toxic animals are kept that are quite capable of causing fatalities. 

Even if a captive dart regained some toxin (evidence that this can happen hasn't been presented here), the risk would be very minimal, I think, considering the unlikely chain of events that would have to occur in order for a human or house pet to be exposed. 

In the grand scheme of things, the risk here is near enough to zero to be zero; any one of us are far, far more likely to be killed by falling televisions or an unknown food allergy. The risk of contracting fatal salmonella from a reptile or amphibian pet is actually much, much more worrisome and is not entirely avoidable (I recall reading that nearly 50% of herp salmonella exposures were from contact unknown to the patient). Yearly 70,000 US cases and 30 fatalities (calculating from overall statistics) are estimated to be linked to captive herps (Reptile- and Amphibian-associated Salmonellosis in Childcare Centers, United States).


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## NateDawg (Oct 16, 2020)

Socratic Monologue said:


> I hope you're not overthinking this. Many (most?) frogs kept in captivity are toxic; some amphibians (Eastern Newts, for one) can and have caused documented human fatalities. In other hobbies such as reef tank keeping, many thousands of keepers care for toxic animals are kept that are quite capable of causing fatalities.
> 
> Even if a captive dart regained some toxin (evidence that this can happen hasn't been presented here), the risk would be very minimal, I think, considering the unlikely chain of events that would have to occur in order for a human or house pet to be exposed.
> 
> In the grand scheme of things, the risk here is near enough to zero to be zero; any one of us are far, far more likely to be killed by falling televisions or an unknown food allergy. The risk of contracting fatal salmonella from a reptile or amphibian pet is actually much, much more worrisome and is not entirely avoidable (I recall reading that nearly 50% of herp salmonella exposures were from contact unknown to the patient). Yearly 70,000 US cases and 30 fatalities (calculating from overall statistics) are estimated to be linked to captive herps (Reptile- and Amphibian-associated Salmonellosis in Childcare Centers, United States).


Being a reef keeping for 10ish years and currently having 3 display tanks along with an appreciation for unique animals in definitely aware of many toxic animals, I've even kept a blue octopus for a few years. Being very new to the dendro world (and with any new hobby) I like to thoroughly learn and continue to learn about it. Plus, with all the unusual animals I've come in contact with, none of them have ever given/ had the potential to cause some nasty pain from contact. An example would be with the rough skinned newt that's common around here, I've handled many of them and have never been poisoned through contact with them, despite them being able to kill a full human very very quickly if consumed. 

But anyway, all this information is very intriguing to me, and I like to learn new stuff. 😁


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## macg (Apr 19, 2018)

Socratic Monologue said:


> Regarding the cat case: I'm not convinced by the implication that a foamy mouth outdoor cat with a frog nearby is a smoking gun that Hawaiian darts are toxic. If the frog was alive/uninjured, this is strong evidence that the frog was never in the mouth of the cat. A recently attacked frog could be expected to be hiding, too; if the frog was easily found, that is evidence that the frog isn't part of this. If the frog was chewed on and merely tasted terrible, that would cause the reaction. If the cat chewed on something else (insect? plant?) a frog could well be nearby. If the cat chewed on another known toxic species of frog, there might well be other frog species nearby -- there are more than one species of invasive _Bufo_ living in high densities in Manoa Valley.
> 
> Other than the fact that people expect dart frogs to be toxic, and are frightened by this thought, there isn't good evidence here.


There was a post later in the thread about a paper analyzing toxins in the Hawaiian auratus population. Relevant part is below:

"Remarkably, although alkaloids of the pumiliotoxin-A class and one decahydroquinoline are still major constituents in skin extracts of Hawaiian frogs descended from the 1932 founding population, histrionicotoxins are absent and a novel tricyclic alkaloid is present."

The probability of the auratus being the cause of the cat's foaming is a bit off topic, but I would say it was appropriate to operate under that assumption. However, agreed it was not absolute fact.

The original question was about the Hawaiian population toxicity, so hopefully that paper clears it up.


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