# Azureus Transporting?



## carola1155 (Sep 10, 2007)

Ok so, this is the first time I've decided to let my azureus attempt to raise their tads in the tank... Now, since sometime yesterday the tadpoles in the eggs have completely absorbed their gills and whatnot, and they have begun to squirm around like they are ready to hatch.

One has broken out of its egg, and the others seem to be pretty close, but every time they move, the parents seem to be more inclined to think that its food or something moving around, not that it is a tadpole. (they stare at it and sometimes even snap at it with their tongue) So my question is, how is it that they know when to transport the tads? should I just step in and move them myself if it doesnt seem like they will do it?

Thanks in advance


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## Julio (Oct 8, 2007)

My personal thought on this is that Aurzues have been so captive bred that the parents in the hobby no longer know how to raise their own tads.


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## carola1155 (Sep 10, 2007)

hmmm... i was a little worried about that... but i know ive seen pictures of azureus transporting before so someone must have had theirs do it somewhat recently...

Should i bother letting them try to tank raise or should i just continue to pull them? I just thought it would be kinda neat to see them do it all themselves


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## holidayhanson (Apr 25, 2007)

I think this is an interesting observation and also raises a great discussion.

Would a frog lose it's natural instincts, developed over a few thousand years, within the time frame this particular frog's lineage has been kept in captivity? 

I would guess this would be 50 years at the longest. Also this is another great reason to know the lineage history of your frogs. Could this be natural selection happening right before our eyes? 

Post your observations and personal opinions.


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## Otis (Apr 16, 2006)

holidayhanson said:


> I think this is an interesting observation and also raises a great discussion.
> 
> Would a frog lose it's natural instincts, developed over a few thousand years, within the time frame this particular frog's lineage has been kept in captivity?
> 
> ...


I don't keep these frogs, but from saurian.net

"_This frog was only discovered by western scientists in the late 60's and its habitat is restricted to some pockets of rainforest on the Sipaliwini savannah..."_

and

"_In the early days of the hobby in this country, back in the early nineties, there were very few bloodlines of this frog in this country. A few frogs had been released by some zoos, and a few wild animals were smuggled into Europe, and the captive bred offspring made there way to the US. In general though there were not a lot of founder bloodlines..."_

I don't think its even been 50 years...


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## frogparty (Dec 27, 2007)

no exp w/azureus but my leucs do this as well. I always assumed they are eating each others eggs (2 females laying 1 male getting busy) but they only eat them when the tads are about to hatch. as eggs they couldn't care less, but when those tads start squirming... night night tadpoles. the male tries to keep them away, but he doesn't guard them 24/7 and once they get the chance-slurp


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## carola1155 (Sep 10, 2007)

Nah this is different from when the females eat each others eggs and whatnot... I had my female eat her own eggs a couple months ago (I had removed the eggs, then put them back when they were getting close to hatching to see if they would transport them). As soon as she saw the eggs she went over and ate them, I guess she thought they were someone elses since they had been gone for a while. (while i watched in horror)

Also, its the male showing this behavior as well... he keeps going at the tads with his tongue.


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## frogparty (Dec 27, 2007)

wierd. guess they're all stomach. must associate movement exclusively with food


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## carola1155 (Sep 10, 2007)

well they havent actually eaten them yet... they will snap at them with their tongue but its not like they pick em up, and as soon as they realize that they arent sticking to their tongue, they wander off...


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## Ed (Sep 19, 2004)

holidayhanson said:


> I think this is an interesting observation and also raises a great discussion.
> 
> Would a frog lose it's natural instincts, developed over a few thousand years, within the time frame this particular frog's lineage has been kept in captivity?
> 
> ...


It wouldn't be natural selection, it would be due to artificial selection even if it was unintentional. 

The short answer is yes. If one considers that egg guarding/transport is at a cost to courting then multiple generations of pulling the eggs can result in a artificial selection for adults that are poor guarders/non-transporters as the male can then devote more time to courting and males that devote more time to courting will have a greater number of eggs and potentially a greater number of offspring. If you look at it the other way, males with poor parental behaviors will have few if any offspring survive. We have eliminated the selection for good parents by pulling and artifically rearing the clutches and transporting the tadpoles for the frogs. 

Now with that said, there are some indications in the literature in other animals, that older parents provide better care as there may be a greater survivorship in offspring of older animals. (see Wiley InterScience :: Session Cookies and the references in http://131.111.101.93/zoostaff/larg/pages/RumPapers/CluttonBrock84a.pdf )

A final issue to consider is that the male is providing good care when you are not present but the feeding response you have noted is due to a feeding response from your presence and any movement triggers the response.... (your presence equals food as you often feed when you are present...). You would need some way to remotely view the frogs to rule this out. 

Some comments,

Ed


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## carola1155 (Sep 10, 2007)

Ed said:


> A final issue to consider is that the male is providing good care when you are not present but the feeding response you have noted is due to a feeding response from your presence and any movement triggers the response.... (your presence equals food as you often feed when you are present...). You would need some way to remotely view the frogs to rule this out.


Well... my tank is right next to my desk, so i dont think my presence would really trigger a feeding response seeing as how they see me allll the time. their feeding response is usually when I open the lid.

By the way, this is probably only the 5th real clutch of viable eggs they have laid... I dont know if that changes anything or not


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## Shady (Sep 18, 2007)

Well I have 3 Azureus (2 female and 1 one male) in a 55 gallon tank. These are my first frogs that I've had for about a yr now and I chose to let them raise there own tads. From what I have seen the male puts the tads on his back and takes them to water. I now have about 5 tads from a couple different clutches. The male seems to only be able to find some of the tads, not all. I keep the tads in the water feature and they seem to be thriving quite well. I do see the parents staring at the water a lot and sometimes I even see them trying to eat a tad but can never get one to stick since they are underwater and tads move pretty quick when they need to. I haven't really seen much of a problem with keeping the eggs in the tank as of yet.


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## Ed (Sep 19, 2004)

carola1155 said:


> Well... my tank is right next to my desk, so i dont think my presence would really trigger a feeding response seeing as how they see me allll the time. their feeding response is usually when I open the lid.
> 
> By the way, this is probably only the 5th real clutch of viable eggs they have laid... I dont know if that changes anything or not


Since I can't observe how you interact with the frogs nor how you interacted with them when you initially aquired them I can't be definitive with this item but some thoughts.. 
If the frogs formed a association with your presence and the appearance of food (this does not mean that you have to feed the frogs every time you sit at the desk but by doing this often enough the frogs form the association, then an irregular application of feeding (reward) can actually strengthen the response) then whan appears to be an irregular appearance of food and you sitting at the desk can actual be a strong reinforcement of this behavior. 


Ed


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## timmeh69 (Jan 12, 2009)

i would imagine them not knowing what to do has more to do with their inexperience rather than them "losing" the ability to do it

the same way that a female tiger might reject her first cubs because she doesn't know what the hell to do with them

as was said transporting tads are dartfrogs way of ensuring a maximum number of their tadpoles survive and thats a true in your viv as it is in the wild, its highly unlikely to just devolve, especially in such a short time.

after a few clutches i'm sure they'd get the hang of it, although that said the fact its close to you and your general activity and them being relatively shy you could be interfering...

but unlikely


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## Ed (Sep 19, 2004)

There is a good chapter on losing reproductive behaviors in Sociobiology by E. O. Wilson and the chance that a behavior will be lost depends on a number of items including pressure to keep the behavior. If we are pulling the eggs then there is no pressure to maintain the behavior and a fair bit towards losing it so it is easily possible that the behaviors can be lost for frogs that do not rear thier offspring as those resources can then be put back into egg laying and courting.

For those that are interested I suggest checking out Sociobiology. 

Ed


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## timmeh69 (Jan 12, 2009)

evolution doesn't really work thay way

i mean when you think about it, removing the egg clutches doesn't mean to them that their tadpoles are safe, it would be the same as if their repeated clutches were eaten by predators, its not like they have made a conscious descision here

i would put my house on it being down to inexperience, these frogs are hardwired to carry their offspring, you don't lose that in a few generations, it doesn't work like that


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## tonying (Mar 6, 2008)

timmeh69 said:


> evolution doesn't really work thay way
> 
> i mean when you think about it, removing the egg clutches doesn't mean to them that their tadpoles are safe, it would be the same as if their repeated clutches were eaten by predators, its not like they have made a conscious descision here
> 
> i would put my house on it being down to inexperience, these frogs are hardwired to carry their offspring, you don't lose that in a few generations, it doesn't work like that


Evolution isn't exactly my field but from what I've come to understand, isn't it at least somewhat feasible that a frog could have a genetic mutation that impairs its ability to care for its offspring? If so, under natural selection, that offspring would have very slim chances of survival, all other things equal, and thus the mutation would disappear. If keepers tend to the tadpoles, the mutation could be carried by the offspring who would then survive.

If so, then these frogs could be the result of such practices. 

I don't know if such drastic mutations are feasible in so few generations but if they are, then wouldn't the above scenario be possible, even if it may be unlikely?


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## timmeh69 (Jan 12, 2009)

tonying said:


> Evolution isn't exactly my field but from what I've come to understand, isn't it at least somewhat feasible that a frog could have a genetic mutation that impairs its ability to care for its offspring? If so, under natural selection, that offspring would have very slim chances of survival, all other things equal, and thus the mutation would disappear. If keepers tend to the tadpoles, the mutation could be carried by the offspring who would then survive.
> 
> If so, then these frogs could be the result of such practices.
> 
> I don't know if such drastic mutations are feasible in so few generations but if they are, then wouldn't the above scenario be possible, even if it may be unlikely?


oh thats entirely possible

but with evolution were talking needle in a haystack. its illogical to assume that this is the case

"if you hear hooves go ahead and think horse... not zebra"

by all accounts alot of people have has issues with tank raising, i had a male leuc with a tad on its back that just would not deposit it, i'd covered the tank with film canisters and cups before i'd put the breeding pair in but he just wouldn't drop it off anywhere. i chalked that down to inexperience because 2 clutches later he was dumping them all over the show


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## Ed (Sep 19, 2004)

timmeh69 said:


> evolution doesn't really work thay way
> 
> i mean when you think about it, removing the egg clutches doesn't mean to them that their tadpoles are safe, it would be the same as if their repeated clutches were eaten by predators, its not like they have made a conscious descision here
> 
> i would put my house on it being down to inexperience, these frogs are hardwired to carry their offspring, you don't lose that in a few generations, it doesn't work like that


No one is saying that this is absolutely what is occuring in this case however there is a significant chance of this happening. The longer we continue to pull and artificially rear the eggs and tadpoles, the greater the risk to these behaviors. 
The problem is that we are not dealing with evolution per se... we are dealing with artificial selection by the keepers rearing the eggs and then the tadpoles to breeding age and size. Since we are equally rearing all the eggs, there is no selective pressure to maintain the reproductive behaviors on the frogs and actually there is a selective pressure to lose those behaviors as they divert energy from producing more eggs. 
These behaviors are going to be coded for by a complex of genes not a single gene and as with many other gene complexes, there is going to be some individual variation in the genes and the expression of these genes (the frogs are not clones nor have they been line bred to gentically identical). So there is going to be differences in parental care and unlike in the wild where better parents should produce more offspring thus maintaining the genetic diversity of the population, captive populations that are artificially maintained like we have been doing with dart frogs can see a shift in the genes as the frogs that divert more energy to producing eggs (since they don't have to rear them) and less to parental care will produce more offspring (as they are producing more eggs and tadpoles) and these genes will become more prevelant until there is a loss of parental care. Significant behavioral changes can occur within surprisingly few generations particularly since most of the dendrobatids in the hobby are the result of line breeding. (for a good example of how fast behavior can change see this paper on medaka JSTOR: An Error Occurred Setting Your User Cookie (which is nicely apt since we try to maximize growth in the frogs as well...)

Ed


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## timmeh69 (Jan 12, 2009)

yeah i understand the theory, honestly and it makes sense

i'm just still not convinced

yeah in the wild if habitat changed or all tadpole predators were removed then yeah all the dartfrogs that just mass spawn without caring would soon dominate a population so i can understand why people might think the same about their captive ones, but it seems like a slightly extreme conclusion when there could be any number of more reasonable explainations?

does anyone know of any studies about frogs down a line? i.e if this has been observed and documented in a pair of dartfrogs, whether their offspring would exibit the same indifference towards tadpoles?


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## Ed (Sep 19, 2004)

timmeh69 said:


> yeah in the wild if habitat changed or all tadpole predators were removed then yeah all the dartfrogs that just mass spawn without caring would soon dominate a population


Actually no they wouldn't. In the wild the differences in parental care and transport would not result in an equilavent survivial of the frogs that are parents. Poor parental frogs would still not have the same survivorship as due to poor care and/or transport there would be fewer tadpoles hatching and fewer tadpoles being transported. 
That is the playing field we have leveled by artificially rearing the eggs and tadpoles and why its of greater risk in a captive population.



timmeh69 said:


> so i can understand why people might think the same about their captive ones, but it seems like a slightly extreme conclusion when there could be any number of more reasonable explainations?


Its not that extreme a conclusion, look at salmon and trout propegation in captivity. Within two generations we produced a fish that has a poor survivial and reproductive rate in the wild because of the way we artificially spawn and rear those fish.... (see Salmon And Trout Hatcheries Cause 'Stunning' Loss Of Reproduction) in two generations there was a significant loss in thier ability to reproduce normally. That is due to the same type of selective pressures we are placing on the frogs. Statistically, it will happen at some point if it hasn't already begun to happen as we are placing a significant pressure on the frogs to lose those behaviors. 



timmeh69 said:


> does anyone know of any studies about frogs down a line? i.e if this has been observed and documented in a pair of dartfrogs, whether their offspring would exibit the same indifference towards tadpoles?


Not published but there are already anecdotal reports already however I suspect that if you dig into the literature you would find changes in species in which studies were preformed in we remove the non-learned parental care. 


Ed


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## timmeh69 (Jan 12, 2009)

thats so bizzare!

i could understand it in fish, i mean they spawn by the hundred, genetic mutations that would cause the behaviour change would occur far more frequently, and that study is in the absence of predators etc etc so essentially, even though their offspring would be picked off in the wild, within the confines of the hatchery they are still "successful"

i'd have thought the behaviour were talking about is different, i mean darfrogs that lay their eggs on land need to transport their tads or they die right? so what we talking here, the gene for not caring being dominant but not passed on because it doesn't work?

so by removing tads were allowing the gene to be successful even though its not?

or is the gene for not caring recessive? in that case is it really ever going to be a problem? like ginger people? (j/k!)


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## Ed (Sep 19, 2004)

timmeh69 said:


> thats so bizzare!
> 
> i could understand it in fish, i mean they spawn by the hundred, genetic mutations that would cause the behaviour change would occur far more frequently, and that study is in the absence of predators etc etc so essentially, even though their offspring would be picked off in the wild, within the confines of the hatchery they are still "successful"!)


It doesn't have to be a genetic mutation. The are multiple versions of the genes in a healthy population and because of this there are differences in coded behaviors. If you change the pressures on what changes the frequencies of these genes in a population you change the hard wired behaviors. If you add a selective pressure that is better for animals that have different behaviors then you can see a more rapid change in thier behavior in succesive generations. There are multiple examples of different gene versions in a population that can affect survivorship. One of the ones we know a little more about are the variations in a population that can code for differences in disease resistance. Different combinations are beneficial against different potential infections. 
If you look at the literature about hatchery fish (in particular salmon and trout), there are also differences in how successful they are in reproducing in the wild. They don't prepare the nests or court correctly (since the egg and sperm collection for hatchery rearing bypasses all of these behaviors) which shows a loss of parenting behaviors. These changes occur rapidly (within a couple of generations)...... 



timmeh69 said:


> i'd have thought the behaviour were talking about is different, i mean darfrogs that lay their eggs on land need to transport their tads or they die right? so what we talking here, the gene for not caring being dominant but not passed on because it doesn't work?
> 
> so by removing tads were allowing the gene to be successful even though its not?
> 
> or is the gene for not caring recessive? in that case is it really ever going to be a problem?


Regardless of how the frogs care for thier offspring etc, the process and selection is the same as the salmon, it just might be slower since the number of offspring is less. 

It doesn't have to be dominant or recessive. It isn't going to be due to a single gene but a complex of genes and changes in the frequency of these genes is going to change the expression of the parental behaviors. The frequency of the expression of these genes is usually going to be minimized in the wild as combinations that result in poor parenting are going to have poor reproductive survivial as the eggs won't hatch or the tadpoles won't get transported or the transporting adult will choose poor deposition sites etc. A mutation isn't required to modify these behaviors.. a simple change in frequency of expression is all that is needed. Because we have a limited genetic population to begin with and often have been in effect line breeding the frogs by breeding siblings together over repeated generations and ensuring maximal surivial without pressures to select for parental behaviors we are in all probability changing the frequency of those genes and thus the expression of those genes. This is a recipe to lose the parenting behaviors of the frogs which to me is one of the things that makes them so interesting. 
One of the benefits we have is because these frogs can have a long reproductive lifespan (over ten years) it should be possible to prevent the loss of these behaviors by ensuring that the frogs show these behaviors before we allow them to produce succeeding generations. This is one of the benefits from joining TWI and regestering your animals. 

Does that help clear it up? 

Ed


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## Tim F (Jan 27, 2006)

I have a pair of azureus that I purchased as adults about 5 years ago. I don’t know how hold they were when I got them, but they were considered breeders. They eat every tadpole as soon as it hatches and begins to squirm, and I’m fairly certain that it’s because eggs have never been left with them before. Their eggs have probably been pulled for years until I got them, so when they began to see these things move for the first time ever they figure them as food. They continue fed on their tads because I do not pull them. If by any chance this is behavior is genetic, it ends with them. However, I ’m sure that this is learned behavior based on prior husbandry, and for this reason, unless I’m dealing with obligates, I prefer to purchase juveniles or younger, and I do not pull eggs at all. My other tincs - all of which I have raised from froglets - transport their tads.


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## Ed (Sep 19, 2004)

Hi Tim,

While that is a definite possible, I have some doubts as other species of frogs that are known to be cannibalistic are pretty effective at determining kinship and avoiding cannibalism of near relatives unless there are not a lot of other options. 

(this might have been best studied in spadefoot toad tadpoles). 


Ed


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## timmeh69 (Jan 12, 2009)

Ed said:


> It doesn't have to be a genetic mutation. The are multiple versions of the genes in a healthy population and because of this there are differences in coded behaviors. If you change the pressures on what changes the frequencies of these genes in a population you change the hard wired behaviors. If you add a selective pressure that is better for animals that have different behaviors then you can see a more rapid change in thier behavior in succesive generations. There are multiple examples of different gene versions in a population that can affect survivorship. One of the ones we know a little more about are the variations in a population that can code for differences in disease resistance. Different combinations are beneficial against different potential infections.
> If you look at the literature about hatchery fish (in particular salmon and trout), there are also differences in how successful they are in reproducing in the wild. They don't prepare the nests or court correctly (since the egg and sperm collection for hatchery rearing bypasses all of these behaviors) which shows a loss of parenting behaviors. These changes occur rapidly (within a couple of generations)......
> 
> 
> ...


so its more of a sliding scale than black and white, i can see that

so like you said they are all surviving, theres no selective pressure, and with no dominant or recessive genes surely the same percentage of carers and non careres will exist in the hobby? if us removing eggs has taken away any selective advantages then that means that the population maybe bigger but the proportion of carers/non carers is the same?


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## Ed (Sep 19, 2004)

timmeh69 said:


> so its more of a sliding scale than black and white, i can see that
> 
> so like you said they are all surviving, theres no selective pressure, and with no dominant or recessive genes surely the same percentage of carers and non careres will exist in the hobby? if us removing eggs has taken away any selective advantages then that means that the population maybe bigger but the proportion of carers/non carers is the same?


Not necessarily. When you look at the energetic costs of parenting you can see that they are pretty costly.. if you have a frog that is putting less energy into parental care (any form of it) then that energy can be reallocated into producing more eggs or calling more to the females. This put frogs that have strong parental care at a disadvantage as they are allocating more energy into care. This gives frogs who devote less energy to parental care the advantage as over time they will produce/fertilize more eggs. 

Ed


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## phender (Jan 9, 2009)

It is possible that we could be selecting for poor parenting by not selecting for good parenting, but what we might be overlooking is that genes don't control all behaviors. Sometimes hormones control behavior and even control genetic expression.

Overcrowded mice will often lose interest in caring for their young. They still have babies, they just don't take care of them. 
Farm raised foxes who were selectively bred to be more docile, started showing genetic variations like curled tails, droopy ears and piebald(pinto) coats because reduced amounts of adrenaline were "turning on" different genes. 
Clownfish start with no sexual orientation, those who make it up the hierarchy become breeding males and then, if they make it to the last step, become breeding females. Obviously their genes aren't changing, but hormones, likely stress related hormones, are turning on different genes.

My guess is that if the frogs are eating their eggs/not transporting their tadpoles, then either they are still too young or they are not receiving the proper stimulus from their environment to produce the proper behavior. i.e., they are too stressed, they are not stressed enough, their environment does not accurately duplicate their natural environment, improper diet, etc. Any of these things could cause improper levels of hormones that could keep the frogs from following through in their reproductive process.

Hope that made sense.


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## timmeh69 (Jan 12, 2009)

Ed said:


> Not necessarily. When you look at the energetic costs of parenting you can see that they are pretty costly.. if you have a frog that is putting less energy into parental care (any form of it) then that energy can be reallocated into producing more eggs or calling more to the females. This put frogs that have strong parental care at a disadvantage as they are allocating more energy into care. This gives frogs who devote less energy to parental care the advantage as over time they will produce/fertilize more eggs.
> 
> Ed


ok you've definately lost me now

i thought we were talking about removng eggs? how would parents spend energy caring if we remove all the eggs. you said we were leveling the playing field by doing so.. am i being stupid here? 

surely if we're removing all the clutches the turnaround for clutch laying would be the same for carers non carers?

have i confused myself?

also in reguard to the question at hand im defo more inclined to go with phenders point, evolution seems a little extreme a conclusion to make on this case anyway, id defo be interested to hear if his frog picks it up later on


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## Tim F (Jan 27, 2006)

Ed said:


> Hi Tim,
> 
> While that is a definite possible, I have some doubts as other species of frogs that are known to be cannibalistic are pretty effective at determining kinship and avoiding cannibalism of near relatives unless there are not a lot of other options.
> 
> ...


Hi Ed. It's a definite. These frogs lay frequently, and eat them as soon as they hatch. Never the eggs, which always develop. I'm sure they'd be fine if I pulled them. I've been observing this behavior with this pair for more than 5 years, and it would be hard to misinterpret what I'm seeing. Housed in a heavily planted 30 gal that is regularly re-stocked with springtails and isos, they do have other snacking options should they miss out on a daily feeding (yes-daily) which rarely happens, so hunger would not be a factor. They are, in fact, larger than most azureus that I’ve seen. I have other azureus that I thought to re-pair them with; however, as I have determined that the both male and female have developed a taste for hatchlings (especially odd since azureus prefer very small prey items), I decided not to, as I would still have to pull the eggs to save them fom a parent.


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## stitchb (Jan 26, 2009)

This is very interesting stuff guys! One thing I love about this forum is how knowlegable the members are.

Does anyone know if any research is being done on this occurance in PDF's specifically? I'd be interested to know the results-heck, if I were a few more years ahead in my career I would like to study it myself HAHA!!

Very cool stuff!


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## Ed (Sep 19, 2004)

Tim F said:


> Hi Ed. It's a definite. These frogs lay frequently, and eat them as soon as they hatch. Never the eggs, which always develop. I'm sure they'd be fine if I pulled them. I've been observing this behavior with this pair for more than 5 years, and it would be hard to misinterpret what I'm seeing. Housed in a heavily planted 30 gal that is regularly re-stocked with springtails and isos, they do have other snacking options should they miss out on a daily feeding (yes-daily) which rarely happens, so hunger would not be a factor. They are, in fact, larger than most azureus that I’ve seen. I have other azureus that I thought to re-pair them with; however, as I have determined that the both male and female have developed a taste for hatchlings (especially odd since azureus prefer very small prey items), I decided not to, as I would still have to pull the eggs to save them fom a parent.



Maybe I wasn't clear. I was having doubts that it was a learned behavior as opposed to a behavior that was occuring due to a loss of parenting behaviors. It's probably too late to make the distinction if the behavior is the result of a loss of parenting skills (so the tadpoles are no longer recognized as reproductive units as opposed to a food item). as opposed simply to a learned behavior. If it was a learned behavior then the frogs would have to overcome the hardwiring that they shouldn't be eating thier offspring (kin recognition) which should be difficult. If the frogs have a weakened parental skills due to gene expression then the eating of the tadpoles is much more explainable.... 

Ed


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## Ed (Sep 19, 2004)

timmeh69 said:


> i thought we were talking about removng eggs? how would parents spend energy caring if we remove all the eggs. you said we were leveling the playing field by doing so.. am i being stupid here?


Unless you are pulling the eggs literally as soon as they are laid, the frogs that then attend or care for the eggs/tadpoles until they are pulled are expending energy and time away from courting/producing the next clutch. Those frogs are at a disadvantage compared to frogs that would then ignore the eggs and let them be pulled. 
Good parenting frogs may also hide clutches and then care for them reducing thier available energy for further clutches. 

We are also not assuming that the lower parenting skills are not linked to some behavior or trait that facilitates survivorship in captivity (as it was with the trout and salmon). If it is linked to a better survivorship then we are artificially selecting for poor parenting simply because the adults are not allowed to care for the eggs/transport the tadpoles. For the first part of this discussion we were assuming the simplest possible example. It is much more likely that there is more linked to it just like the trout and salmon. 





timmeh69 said:


> surely if we're removing all the clutches the turnaround for clutch laying would be the same for carers non carers?


Only if the eggs are pulled as soon as they are laid. A frog that lays the eggs and then forgets them is better off in that example than a frog that attempts parental care and may continue to visit the site repeatedly once the eggs are pulled causing a loss of energy. That is off course that this is not linked to other survivorship issues like the trout and salmon... If it is linked to traits that allow better survivorship in captivity then not allowing the frogs to care for the eggs and care for the tadpoles will cause a shift in the expressed genes. 




timmeh69 said:


> also in reguard to the question at hand im defo more inclined to go with phenders point, evolution seems a little extreme a conclusion to make on this case anyway, id defo be interested to hear if his frog picks it up later on


Which is why we are not discussing evolution but artificial selection for expression of genes. 

Ed


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## Ed (Sep 19, 2004)

Hi Phil.




phender said:


> It is possible that we could be selecting for poor parenting by not selecting for good parenting, but what we might be overlooking is that genes don't control all behaviors. Sometimes hormones control behavior and even control genetic expression.


Without getting into epigenetics... the problem is that in the fox example, there were changes in gene frequency and expression while the others are not the best comparisions (sorry for the bad wording here but I'm pretty tired). 



phender said:


> Overcrowded mice will often lose interest in caring for their young. They still have babies, they just don't take care of them.
> Farm raised foxes who were selectively bred to be more docile, started showing genetic variations like curled tails, droopy ears and piebald(pinto) coats because reduced amounts of adrenaline were "turning on" different genes.



There are a lot of things that go into maternal care in mice including behaviors that are coded by the amount of care they recieve when pups. Under crowded conditions, pup care is interefered with and this can be a source of this behavior in crowded conditions. There are also external factors that make this an example that really doesn't apply to frogs or this situation. 


For the foxes a good review can be found here http://www.floridalupine.org/publications/PDF/trut-fox-study.pdf and it has to be noted that any program in which a species is kept in captivity, unless massive effort is expended to prevent it, there is often significant mortality before the animals get established (as those that have genes that allow them to tolerate captive conditions survive to breed). This in the older days was called failure to thrive or maladaption syndrome. So when ever we have a species breeding in captivity we have already undergone one selection process (and this effect can occur in the eggs that are fertile and fail to develop as well as tadpole death in frogs as much as death in metamorphs or adults can affect it). 




phender said:


> Clownfish start with no sexual orientation, those who make it up the hierarchy become breeding males and then, if they make it to the last step, become breeding females. Obviously their genes aren't changing, but hormones, likely stress related hormones, are turning on different genes.


Actually clownfish start out as males. They hatch as males and then develop into either subadult females then females or adult males when they migrate to an new anemone or when an fully mature animal changes into a female or dies. The expression of the sex is under hormonal control which is determined by genetics. For those interested in a good reference on this I suggest SpringerLink - Journal Article 



phender said:


> My guess is that if the frogs are eating their eggs/not transporting their tadpoles, then either they are still too young or they are not receiving the proper stimulus from their environment to produce the proper behavior. i.e., they are too stressed, they are not stressed enough, their environment does not accurately duplicate their natural environment, improper diet, etc. Any of these things could cause improper levels of hormones that could keep the frogs from following through in their reproductive process.


When dealing with herps, the more normal sequence if there is stress due to enviromental conditions not being correct is to not breed and in fact there is suppression of the hormones required for reproduction. This process is pretty conservative across taxa so we can consider the studies done with reptiles. The stress actually inhibits reproduction by inhibiting the production of hormones in levels needed for reproduction. 

Ed


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