# Environmental stimuli that encourage breeding



## Guest (Sep 28, 2004)

This is going to sound crazy, but what if multi-generation frogs are breeding less because they have less stress on their populations than do wildcaughts?

A loose example: My friend in CA helps to manage animals at an african wild animal park. His herd of gazelle were not producing. The managers then put a cheetah holding in plain view of the gazelles. The cheetas and the gazelles watched each other. The gazelles started popping out babies like mad the next season.

Even though our husbandry is lacking in so many ways, life is still really easy for frogs in captivity. Mortality is relatively low. The frogs in later generations do not have the high stress to preserve their genes as fast as possible. The frogs that survive the stress of the wild and then survive the stress of being imported are going to feel the stress of needing to reproduce like crazy. However, our many of our F whatevers don't even have to compete with other frog species, let alone members of their own. 

In addition, all of the tricks we use to make sure most of our eggs hatch, and froglets live, is severely limiting the already diminished effects of natural selection in captivity. With medicine and stuff we make sure frogs live and reproduce that probably shouldn't have made it past froglethood. We could be breeding what should have been discarded genes back into the population again and again, and perhaps reduced production is one of the affects. 

Of course the answer to the downsized reproductions is most likely an extensive patchwork of factors, and maybe these are factors that can be thrown into the pot. The one certainly may explain why a period of less food or "dry season" seems to encourage breeding behavior after the fact.


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## melissa68 (Feb 16, 2004)

Lydia,

I think you make some good points. 

Ideal weight is another one. Anyone ever noticed their frogs don't breed as much when they are fat - overweight - well fed? I know Kyle had this issue, slimmed his frogs down and they began to breed. 

We had bearded dragons, and were never able to get them to breed - ours were always healthy, lazy chunks. We had frilled dragons and we were able to breed them - we watched their diet closely. 

Anyone else ever noticed the relationships between weight & breeding?

Melis



Lydia said:


> This is going to sound crazy, but what if multi-generation frogs are breeding less because they have less stress on their populations than do wildcaughts?
> 
> A loose example: My friend in CA helps to manage animals at an african wild animal park. His herd of gazelle were not producing. The managers then put a cheetah holding in plain view of the gazelles. The cheetas and the gazelles watched each other. The gazelles started popping out babies like mad the next season.
> 
> ...


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## kyle1745 (Feb 15, 2004)

Ya I had this with my Leucs and Azureus, both were over weight and after dropping the food and the weight they started to breed. Both took about a month or so 2 drop the wieght, and to be honest I have a hard time still not overfeeding.



melissa68 said:


> Lydia,
> 
> I think you make some good points.
> 
> ...


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## JWerner (Feb 17, 2004)

Lydia -
Good observation. A thread should be started regarding various environmental stimuli that encourage breeding. I think this is great stuff and hope the moderators could move it to a new thread because many might only read this thread because it deals with receiving eggs that are bad and what are the reasons/solutions. 
I'm not sure if the use of the word 'stress' is accurate. The 'dry season' nature can be stressful to frogs, but is completely natural. Earlier in this thread it was mentioned that bad eggs cold be due to overbreeding because a dry season might not be given by the hobbiest. Some might feel that neglecting their frogs is stressful. I agree, but only to a certain extent. Not watering and feeding on your 'normal' night could happen because you're busy or slackin' However, environmental changes in moisture, temps, food happen all the time. What you perceive as being a bad owner could be entirely natural to the frogs, but remember this is only to a certain extent because these creatures do depend on you. I would like to see someone post the dry seasons and wet seasons for Peru, Ecuador etc.

Shaking things up does exactly that. I believe changes in what is regarded as 'normal' is good.

When I use to breed dwarf monitors. I would move them 1.1 or 1.2, they would breed well for a certain length of time. They would breed every 2 - 4 months. After time, this became normal. At the four month point, if no breeding had taken place, I would vacuum about 2" of their soil away and spread new stuff. For some reason, breeding occured - usually - within a month. 
The ultimate example of shaking things up and the results that could happen occured with my frogs last week. For over two years I had a group of red amazonicus that never bred. I changed around their terrarium 4 - 5 times during the two years, but always kept the group together. This last spring I bought a group of 4 more - same line. Never any breeding. Last week I put together a new terrarium and took a male from one and a female from the other and placed them in a new terrarium. Within 24hrs, I had eggs. I repeated the precess the next night - a male and female from different enclosure into a new terrarium. Poof.... had eggs. I did the same the third night - new pairing and received eggs. I had 2.1 left and tossed them into a holding tank because I did not have a fourth new tank designed. They also laid eggs.

Jon


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## geckguy (Mar 8, 2004)

Jon after people read that post, I think your amazonicus list is gonna get alot longer!


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## Guest (Sep 29, 2004)

Thanks for the additional discussion and input. We need as many takes on these things as possible to put together the big picture.

I'm probably just being a stiff when I say this, however I would like to defend my use of the term stress.

I do understand where people would shy away from things that are labeled to give their frogs "stress" because stress with us has such a negative connotation. I think this is anthropomorphism and could further contribute to the misunderstanding of the way some of the world works. 

The fact is that stress (or changing conditions, or conditions that force "innovation", or whatever makes it sound better to you) on many biological systems encourages growth, and generally strengthens organisms fit to reproduce and weeds out those that are not.

Obviously there are exceptions to everything. Anyone who's messed with coral has experienced that first hand 

In any event, I don't mean to tell people what's what. Just thinking about stuff.


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## Guest (Sep 29, 2004)

It'd be cool if some people from the bad eggs thread could cut and paste some of their environmental stuff that didn't get moved, too, to round out the new thread.


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## geckguy (Mar 8, 2004)

I had a leucs that weren't doing anything for awhile so I split up the group and gave them a new cage and within a 2 weeks I had eggs, I think the "stress" of a new enviroment definitely helps some frogs get going.


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## Homer (Feb 15, 2004)

Lydia,

It's an interesting observation that stress would cause reproductive activity. It does ring some bells with me, as my endocrinology prof. did studies related to cortisol levels inducing the ritualistic mating behaviors so often seen in birds. If I'm not mistaken, stress usually elevates cortisol levels in many animals . . . might there be a connection there?

I don't know, just hypothesizing and extrapolating.

Homer


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## AQUAMAC (Jul 27, 2004)

Anyone out there have any ideas about temp and misting amounts for breeding stimuli in pumilio. I get an occasional call out of my bastimentos but thats about it...right now my cage is around 76-78 and full of bromiliads..still nothing.

Anyone have similiar suggestions for almirante? I know I saw someone post that they got tads, but I could not find the person when I went back to look. I got one batch of bad eggs from these guys and thats about it...the male called, the female layed, but no good eggs

Also are you guys housing your bastimentos in pair or groups?

Thanks for the suggestions.

-Mike


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## EverettC (Mar 9, 2004)

Well if you have pumilio it's probably been reccomended to you to keep them in 1.1 pairs. So, to test this theory, somebody could put 2.1 or 1.2 in a 20g and see what happens. I would do this myself but I only have 2 (probably male) almirante. As for the almirante question, the thread is http://www.dendroboard.com/phpBB2/viewtopic.php?t=2834 . Good luck w/ the almirante


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## Darren Meyer (May 22, 2004)

Patrick keeps his @ 1.1 , so as far as I know he is the man where pumilio are concerned . I also keep mine in a 1.1 groups . They lay all the time , I never had any luck in groups . I find that I don't mist alot or do anything really special ,just keep the brom water fresh seems to do the trick . 
Good luck , it's really cool to see a little baby pumilio hopping around , expecally when you diden't know that they had even been laying eggs !!
Have fun !! 

Darren Meyer


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## EverettC (Mar 9, 2004)

*crosses fingers and hopes that when AZDR comes up I can get a female * Hehe I mist once every other day or so. I change the times around so one day i'll mist in the morning and one day at night. I really hope it works, this is why I got into the hobby (to watch the adults raise the young).


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## steelcube (Mar 17, 2004)

Jon Werner said:


> Last week I put together a new terrarium and took a male from one and a female from the other and placed them in a new terrarium. Within 24hrs, I had eggs. I repeated the precess the next night - a male and female from different enclosure into a new terrarium. Poof.... had eggs. I did the same the third night - new pairing and received eggs. I had 2.1 left and tossed them into a holding tank because I did not have a fourth new tank designed...


Could it be possible that some frogs are reluctant to breed with tank mates that were together growing up?? 

Could it also be possible that introducing frogs that came from different tanks, to a new environment, triggers the same response as if the frogs travel to a new area and meet the locals? Thus they are interested to spread their genes around?

Do they have that kind of intellegence?

SB


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## Guest (Sep 29, 2004)

Hi,
I have 4 green pumilios and have 3 in a 20 vert.I have them in a 2.1 right now and the males have some calling duals but no major fighting yet.They are still young and are approximately 5 months old so I keep a close eye on them to make sure they aren't stressing each other out.
Mark W.


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## bbrock (May 20, 2004)

EverettC said:


> Well if you have pumilio it's probably been reccomended to you to keep them in 1.1 pairs. So, to test this theory, somebody could put 2.1 or 1.2 in a 20g and see what happens. I would do this myself but I only have 2 (probably male) almirante. As for the almirante question, the thread is http://www.dendroboard.com/phpBB2/viewtopic.php?t=2834 . Good luck w/ the almirante


My 1.2 group of Nic. blue jeans has been breeding for years. I've actually witnessed egg dumping by one female who deposited eggs on the freshly fertilized clutch of the other. In the early days the group was 2.2 and competition among the males limited reproduction to almost nothing.

Personally I think the 20g vivs that many people are trying to breed pumilio in are too small. Yes, I know that several people are having luck breeding pumilio in 20T tanks but my theory is that this is approaching the lower limit of what will work and the odds of success increase as you move to larger tanks.

I have not quite figured out the relationship between misting and reproduction. I agree with Darren that flushing the broms with fresh water is key. Early on I kept my pumilio viv pretty wet and the male called for awhile and then stopped, then I cut way back on misting and the male started singing like mad but no reproduction. Then I cranked up the mist again and started getting reproduction. I've kept it that way for years with misting about 5 times a day and the frogs produce froglets at a slow but steady pace. I think the misting is not necessarily a trigger for mating as the males just sing or don't sing according to their own schedule. However, I do think different populations of pumilio may have different egg care behaviors and the amount of misting is important for egg maintenance. The thinking (and I can't take credit for this) is that pumilio from wetter regions are more sloppy about keeping their eggs wet while those from slightly dryer habitats are more deligent. Indeed, I have found clutches of eggs dried out on leaves if I forgot to fill the misting reservoir for a few days.

So back to the original issue of sex ratios, again I think this is somewhat dependent on the size of the viv. In a very large viv, you can probably get by with a group but this will vary with individual frogs. For the most part, 1.1 is probably best but then we don't know how important mate choice or competition might be in driving pumilio reproduction either.


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## Guest (Sep 29, 2004)

steelcube said:


> Could it be possible that some frogs are reluctant to breed with tank mates that were together growing up??



I have experienced the same thing my trio of Tincs that grew up together and were not intreasted in breeding even at 13 months until I seperated one female away from the group and left a 1.1 ratio. Which they didn't breed either. When I reintroduced the female back into the group a month or so later, I had eggs the next day, and had to remove the OTHER female due to the sparing matches between the two females. :shock: They've been breeding ever since but the only thing I did to "trigger" it was the seperation period, but it's the same tank they grew up in they are now breeding in.


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## bbrock (May 20, 2004)

steelcube said:


> [Could it be possible that some frogs are reluctant to breed with tank mates that were together growing up??
> 
> Could it also be possible that introducing frogs that came from different tanks, to a new environment, triggers the same response as if the frogs travel to a new area and meet the locals? Thus they are interested to spread their genes around?
> 
> ...


I have suspected that something like this might happen but hadn't really thought about the possible evolutionary significance. I don't think it requires intelligence though. Interesting thought.


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## steelcube (Mar 17, 2004)

> Could it be possible that some frogs are reluctant to breed with tank mates that were together growing up??


Could it be an anti inbreeding mechanism??



> Could it also be possible that introducing frogs that came from different tanks, to a new environment, triggers the same response as if the frogs travel to a new area and meet the locals? Thus they are interested to spread their genes around?


For the females I guess it's for producing stronger/variable offsprings.

SB


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## EverettC (Mar 9, 2004)

What steelcube says makes a lot of sense. We know that if a species interbreeds too much the offspring come out bad(small, stupid, etc) or deformed. This same reason could also be a part of the spindly legs issue, although it happens in the wild as well. Just because something lives in the wild doesn't mean it won't interbreed, but the chances are greatly reduced.


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## Guest (Sep 30, 2004)

With the intelligence issue, I think biochemists are finding that different "stresses" produce different hormones which produce different behaviors. It looks smart, though. 

Evidently, based on the observations stated here, frogs don't have a very long memory when it comes to their peers. That's really interesting. How long was the period of separation?


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## bbrock (May 20, 2004)

EverettC said:


> What steelcube says makes a lot of sense. We know that if a species interbreeds too much the offspring come out bad(small, stupid, etc) or deformed. This same reason could also be a part of the spindly legs issue, although it happens in the wild as well. Just because something lives in the wild doesn't mean it won't interbreed, but the chances are greatly reduced.


Those who know me from frognet know it was only a matter of time before I said something about wolves. Actually Everett, many species in the wild not only inbreed frequently but it can actually be evolutionarily advantageous. Let me think of an example..... OH, how about WOLVES? There is some pretty compelling evidence that the social structure of wolves actually encourages a fairly high degree of inbreeding. A wolf pack typically consists of an alpha pair and 1 or more litters of their pups (normally 2 or more of different ages in established packs). Normally only the alpha pair breed. Life is hard being alpha because there is always someone else in the pack that wants to breed. Well, if an alpha gets knocked off their throne, the most likely animal to displace them is one of their own kids who then gets the privilege of breeding with Mom or Dad! Then when the other alpha goes down, the alpha pair are likely to be siblings! So why would this be an advantage? Because wolves historically occupied an enormous range covering a whole slew of different climates and habitats that offered different prey species. Wolves that live up north and eat moose would have a hard time using their same hunting strategies to subsist on jack rabbits in the desert. Inbreeding helps to rapidly fix the genes that make particular wolves adapted to a specific location. In other words, a caribou chowing wolf would not find much advantage in mating with a rabbit chasing, thin-furred, dwarf. Outbreeding actually can be too much of a good thing. I would not be surprised if wide ranging and variable species like pumilio don't also benefit from some mechanisms that produce little mini-bottlenecks in gene exchange.

BTW, the CDC released a study a few years ago that looked at the effects of inbreeding in humans. They studied thousands of cases but found that the incidence of congenital disease was no higher even among offspring of cousin-cousin marriage than from a random sample. So taking your cousin to the prom is no longer something to be ashamed of!

So why outbreed at all? Because the world is an ever changing place and outbreeding mixes up genes in a never ending array of combinations. Having such a mix of genes increases the odds that when the world DOES change, some of your relations will have the magic genes to be able to at least survive the change as a species and maybe even thrive in the new conditions.

So the debate on outbreeding vs. inbreeding is rather complicated. Yes, inbreeding tends to increase the rate of homozygosity which allows things like deleterious recessive genes to rear their ugly heads. But homozygosity may also fix the very best genes for a population to thrive under current conditions. The trade-off is that if conditions change, then you only have one set of plans, no variability to let your species adapt to the change. Like so many things in life, there is no black and white, only grey.

So where does that leave us with the question of breeding triggers? I don't know. I think it makes some sense that animals reared together just might not really consider each other mates. It certainly works that way with humans, why not frogs? But I think Lydia is right in that frogs don't have a terribly long memory at least when it comes to recognizing individuals. Many people have noticed that separating a pair of frogs for a period and reintroducing them tends to stimulate breeding. Maybe the frogs just get use to seeing each other outside of a sexual context so the sight of one another just doesn't flip the switch. Maybe after they've been apart and reintroduced they just kind of think, now here's something new, and the excitement triggers sexual behavior. Maybe frogs are swingers at heart.


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## EverettC (Mar 9, 2004)

Wow that was a long post brent . Highly informitave though, I had no idea about the wolves. That's really interesting and makes sense in that case. I guess you could apply this to the pumilio on the islands in Panama. And that would explain the random color changes we sometimes see in the hobby (white basti's etc). This is fun stuff to talk about; intelligent conversations about interbreeding and taxonomy and the like, good; high school conversations about football and girls...too many and not enough thinking...


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## steelcube (Mar 17, 2004)

bbrock said:


> Those who know me from frognet know it was only a matter of time before I said something about wolves. Actually Everett, many species in the wild not only inbreed frequently but it can actually be evolutionarily advantageous. Let me think of an example..... OH, how about WOLVES? There is some pretty compelling evidence that the social structure of wolves actually encourages a fairly high degree of inbreeding. A wolf pack typically consists of an alpha pair and 1 or more litters of their pups (normally 2 or more of different ages in established packs). Normally only the alpha pair breed. Life is hard being alpha because there is always someone else in the pack that wants to breed. Well, if an alpha gets knocked off their throne, the most likely animal to displace them is one of their own kids who then gets the privilege of breeding with Mom or Dad! Then when the other alpha goes down, the alpha pair are likely to be siblings! So why would this be an advantage? Because wolves historically occupied an enormous range covering a whole slew of different climates and habitats that offered different prey species. Wolves that live up north and eat moose would have a hard time using their same hunting strategies to subsist on jack rabbits in the desert. Inbreeding helps to rapidly fix the genes that make particular wolves adapted to a specific location. In other words, a caribou chowing wolf would not find much advantage in mating with a rabbit chasing, thin-furred, dwarf. Outbreeding actually can be too much of a good thing. I would not be surprised if wide ranging and variable species like pumilio don't also benefit from some mechanisms that produce little mini-bottlenecks in gene exchange.


Check this site: 
http://www.wolf.org/wolves/learn/basic/faq.asp#3 
They wrote: "Wolves usually live in packs which consist of the adult parents, referred to as the alpha pair, and their offspring of perhaps the last 2 or 3 years. The adult parents are usually unrelated and other unrelated wolves may sometimes join the pack. " 

and http://www.wolf.org/wolves/learn/basic/faq.asp#21 

their home (International Wolf Center): 
http://www.wolf.org/wolves/index.asp 

Just to put things in perspective.... 

Ever heard story about cheetah?? Because of several reasons, cheetah are highly inbred. So badly that some of the offsprings simply born and die. 

Check this site: 
http://www.cheetah.org/ 

About their genetic diversity: 
http://www.cheetah.org/?nd=aboutcheetah-03 

I don't know about wolves... have there been DNA tests to find out genetic variability between and inside a pack?? 

I don't know Brent... I have doubt about the compelling evidence regarding wolves. 


SB


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## Guest (Sep 30, 2004)

The source you found steelcube may be referring to how things USED to be, with the wolves. Like cheetahs, the populations of wolves are now isolated, and are forced to breed with their cousins. Actually, as someone else said, linebreeding is how we got the breeds of dogs, horses, and everything else domesticated. When done in excess, inbreeding can be bad. When done in moderation, we mold whatever to the characteristics we want. Aka the hypomelanistic and albinism fetish among many herp fanciers. 

The simplest form of stress dictating methods of reproduction is some forms of fungi. Some mycotas will only reproduce sexually if there are less than ideal conditions, or if the conditions change during the reproductive cycle. If the Ph and temperature and food supply remains the same, and the fungus is doing well in that environment, then it doesn't need to change its offsprings' genes, because if IT is doing well in the constant conditions, then its genetically identical offspring will also do well.

If the fungus is not doing too well in an environment, or if conditions change, the fungi will reproduce sexually to ensure that their offspring have a chance at a recombination of genes that will be more successful in the current environment than their own. 

Now, this same factor is seen all the way up to mammals, even wolves. When things are good, they aren't going to move out of the range of their group of packs. They will interbreed, and all become related to one another. Inbreeding then ensues. If, say, all the white men come and shoot all of the caribou in the group's region, (a stress of not having enough food to go around), then some packs will up and leave and find food in a different group of packs' area, and then add their new blood to their new group of packs. 

Female cheetahs normally have their own territory within their Mom's BIG terrritory, which is within a male's even BIGGER territory. There was always overlap breeding when a male cheetah bred with his daughters before he was ousted by a new male (which very well could have been her brother or cousin) and bred with her again. So even though the cheetah population is really small and inbreeding is astronomically worse, there still was inbreeding going on. 

Her's the kicker: The gene pool that was being inbred to was bigger back then, for a lot of different organisms, so the problems that we see today didn't crop up in as severe of numbers. Make sense? 

Probably not, I used WAY too many words!


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## bbrock (May 20, 2004)

steelcube said:


> Check this site:
> http://www.wolf.org/wolves/learn/basic/faq.asp#3
> They wrote: "Wolves usually live in packs which consist of the adult parents, referred to as the alpha pair, and their offspring of perhaps the last 2 or 3 years. The adult parents are usually unrelated and other unrelated wolves may sometimes join the pack. "


Not exactly true. I thought my last post was long enough without going into the details of wolf pack structure. Dispersing wolves expanding into new territory, as is happening in Yellowstone and was in Minnesota and Wisconsin a decade ago, tend to find unrelated mates to form new packs. However, wolves dispersing into saturated territory tend to get killed by the resident pack and recruitment for alpha tends to occur from within. Therefore, in areas where wolves are well established and available territories are occupied, you get an increase in the rate of related matings.



> and http://www.wolf.org/wolves/learn/basic/faq.asp#21


Check out the dates on those citations. When Mech wrote his book in 1970, little was known about wolf ecology and his book really advanced our understanding of these animals. Now wolves are probably the most studied vertebrate on the planet and a lot has been learned in the 34 years since Mech published that book. The Lopez book is not even a scientific work and I don't understand why it continues to be cited on popular web pages about wolves. Lopez was exploring the relationship between wolves and humans through history.[/quote]



> Just to put things in perspective....
> 
> Ever heard story about cheetah?? Because of several reasons, cheetah are highly inbred. So badly that some of the offsprings simply born and die.


I acknowledged that inbreeding can fix deleterious traits. This has also happened to the Florida panther. The point is that inbreeding is a two edged sword that has cost/benefit trade-offs. Our job is to figure out where our frogs fit in this mix.



> I don't know about wolves... have there been DNA tests to find out genetic variability between and inside a pack??
> 
> I don't know Brent... I have doubt about the compelling evidence regarding wolves.
> 
> SB


DNA tests have been done and I'm sure somebody has looked at the within and between pack relatedness but I haven't read any. However, there have been direct observational studies in the arctic and Yellowstone that have actually tracked pack composition over time. Yellowstone particularly has yielded great information since all of the packs within the park have been know done to the individual animals since their reintroduction. In a nutshell, dispersing animals find unrelated mates to form new packs but established packs tend to recruit new alphas from within. New animals from outside a pack have been observed to join an existing pack but only after a very long "courtship" where the newcomer lives at the fringe of pack society to kind of habituate the pack to its presence.

But think about it. In North America alone wolves ranged from the arctic to Mexico. They fed on everything from Musk oxen, to moose, to bison, to deer, to beaver, to rabbit. Their body size ranges from 100+ lbs in the north to a meager 40-60 lbs in the south. These animals rely on a combination of body type and social hunting strategies to survive in THEIR particular part of the world. Free gene flow across the species range would tend to dilute site specific traits that made wolves adapted to a particular locality. A certain amount of inbreeding helps to fix and conserve those traits. Wolves seem to have hit on the right mix to both benefit from a fair amount of inbreeding while still exchanging enough genetic material across the species range to keep them viable as a species. So viable in fact, that the only large mammalian predators to have ever occupied a larger species range on the planet are _**** sapiens_ and _Panthera leo_.

Now wolves might present a pretty extreme example of the potential benefits of inbreeding but surely we can imagine that some species of frogs might also benefit on a more subtle level. I just think we need to start thinking about our frogs in terms of metapopulations rather than as discrete little populations of morphs.

I do have a couple citations on the inbreeding tolerance and potential advantage of wolves but unfortunately my wolf literature is still in boxes in storage. Sorry about that.


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## andersonii85 (Feb 8, 2004)

Homer said:


> Lydia,
> 
> It's an interesting observation that stress would cause reproductive activity. It does ring some bells with me, as my endocrinology prof. did studies related to cortisol levels inducing the ritualistic mating behaviors so often seen in birds. If I'm not mistaken, stress usually elevates cortisol levels in many animals . . . might there be a connection there?
> 
> ...


Homer,

I have read that cortisol has an affect on testosterone levels in birds. I believe the release is triggered by environmental conditions. Stress is such a relative term. There are like a billion ways of defining it. I think we should define it first and then everyone can talk about so that we may be on the same page.

Justin


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## Homer (Feb 15, 2004)

andersonii85 said:


> Homer said:
> 
> 
> > Lydia,
> ...


Justin, 

I agree that the term "stress" is amorphous, but I think it is probably beyond the scope of our discussion to try to define it here. To my understanding, you are correct that cortisol levels in birds is usually triggered by photoperiod and other environmental factors. 

However, I think you misread me. What I was trying to state was that stress (actual adverse environmental triggers like we have talked about above--dry periods, cool periods, lack of food, rapidly changing surroundings, etc.) also tends to elevate cortisol levels in some animals. 

What I was contemplating is this: if we know that increased cortisol levels trigger mating activity in animal A, and we know that stress can trigger a cortisol spike in animal B, is it possible that stress can cause mating activity in animal A? I was not trying to indicate that photoperiod and seasonal environmental changes are equivalent to stress (although some definitions of stress are that broad, and I guess that some of my above examples do fall into those seasonal changes in some areas).

True, my correlation was not documented with hard data, and even logically it doesn't necessarily follow, but I think there was enough correlation between the anecdotal statement by Lydia and some of the other posts for me to at least ask if there is a possibility that external stressors might trigger endocrine pathways that are well documented to cause mating behavior in some animals. It not only seems possible to me, but at least plausible, don't you think?


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## Homer (Feb 15, 2004)

P.S.--Justin, were some of the references you read written by a Dr. Schoech? Just wondering.


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## andersonii85 (Feb 8, 2004)

Homer,

Thanks for the explanation as I was a little unsure as to what you were trying to get at. I was actually reading a buddy of mine's paper (unpublished). He goes to Cornell and is a big "birder". He's actually precepted by that guy that did that famous behavioral experiment with birds and migration- the study consisted of placing birds in a cage within a planetarium. The set the "stars" to see if birds used celestial navigation. Awesome study! I wish I could remember that guy's name. 

Anyway, in regards to stress elevating cortisol levels: First, I believe that the type of stress is what would matter. If we rule out environmental conditions and photoperiod what other stresses would be important to frogs? Parasitism? Competition (inter as well as intra)? Predation? I don't expect to get an answer to this as I think (and you do too) that research would need to be completed. How to measure cortisol in frogs? Hmmm..... 

Personally, I don't think that amphibians would be triggered to mate by stress, but your thoughts are certainly interesting. 

Justin


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## Homer (Feb 15, 2004)

andersonii85 said:


> Homer,
> He's actually precepted by that guy that did that famous behavioral experiment with birds and migration- the study consisted of placing birds in a cage within a planetarium. The set the "stars" to see if birds used celestial navigation. Awesome study! I wish I could remember that guy's name.


Yeah, I remember reading that study . . . I have long since forgotten the author's name (if I ever noticed it to begin with). However, it was an interesting read. 



> Anyway, in regards to stress elevating cortisol levels: First, I believe that the type of stress is what would matter.


I would bet that it varies by species as to what type of stress causes cortisol levels to rise, and I'm sure that there are other pathways that might shut off the mating behavior when the stressor is not of the particular type that usually causes mating behavior.

Regardless, generalized stress (mortgage, work, etc.) is a prime trigger for elevated cortisol levels in humans, and that was what had me thinking. However, as I recall, the levels in birds were astronomical when compared to baseline levels in order to trigger mating behavior.



> If we rule out environmental conditions and photoperiod what other stresses would be important to frogs? Parasitism? Competition (inter as well as intra)? Predation?


I did not suggest ruling out environmental conditions, but rather seasonal environmental conditions. I agree, if you rule out environmental conditions, you rule out almost all forms of stress.



> I don't expect to get an answer to this as I think (and you do too) that research would need to be completed.


Agreed, but that does not negate the worth of hypothesizing here.



> How to measure cortisol in frogs? Hmmm..... "


I would imagine you do it the same as you do in birds--use a radioactive tag. Definitely not something I'll be doing on my budget and in my facilities.



> Personally, I don't think that amphibians would be triggered to mate by stress, but your thoughts are certainly interesting.
> 
> Justin


I don't know. I'm not sure I am convinced one way or another. However, how do you explain the fairly common phenomenon of frogs laying right after being shipped or introduced into a new tank? It seems like this is a plausible theory to explain that phenomenon.

Just some thoughts.

Homer


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## rburnj (Aug 19, 2004)

hey justin,

The ties between stress and cortisol levels I beleive has been established in a number of case studies. I have read numerous papers on this and its data has been collected over a number of taxons (birds, mammals, etc..). In terms of testing these levels, a lot of the time it is done through fecal cortisol. To my knowledge, the testing of fecal cortisol, as well as other hormones such as testosterone, can be tested through fairly simple immunoassay techniques. However, as we all know....getting fecals on frogs is a challenge. Getting a large enough amount to work with is an even bigger challenge. In terms of stressors...there are many types like you said. Environmental plays a part but a lot can be mate or rival induced. For example, there have been studies on ringtailed lemurs. The fecal cortisol levels were take in order to figure out mating success and hierarcy. However, it is hard to make direct correlations dealing with stress on mating behavior but increased cortisol has been seen to tie into mating an breeding. 

As you all have pointed out, frogs do seem to breeding in situations that we would deem stressful (new enclosures, after shipping, etc..). This may be clearly implied, but animals in times of stress may want to pass on their genes for fear of death etc. Therefore, we take them out of their shipping container and a day later have eggs. I believe a lot has to do with their interaction with one another. The stress of another females presence may cause competition and ovulation. Same can be seen in males. Breeding is very complicated and I don't think it will ever be a considered concrete science. We may know the mechanisms and pathways to which it occurs, but reasons for why it occurs will always be questioned. 

This is also a topic that is studied at a number of institutions and unversities. I had talked to a woman at the Smithsonian and their endangered species conservation department and I was looking into doing this work with thailand fishing cats and reproductive success after I graduated college. This is an expteremly interesting topic...one of which I am entertaining for my grad research at the moment. Topics like this are exteremely important to link the ties between health, conservation and breeding success of endangered species. By understanding the bodies hormone response output and its interactions in conjunction with stress and displayed behavior...we can then implement better species survival plans for in-situ and ex-situ coservation practices. Alright, enough blabbing....but hey maybe it will help with creating better conditions for breeding our frogs. Which I know would benefit almost everyone on this board. Awesome post guys.

-Ryan


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## Homer (Feb 15, 2004)

Thanks for an enlightening post, Ryan! :shock: :idea:


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## andersonii85 (Feb 8, 2004)

Ryan,

Thanks for the response. I grow more curious about this whole phenomenon everyday in terms of frogs breeding in conditions that seem less than ideal. I can't help but recall my days of keeping snakes. Some species were so hard to get breeding, but then I would place the couple in a small box or in a bag together and sure enough the male would do his thing and the female would do hers. A few months later I would have eggs (with kings and milks) or neonates (ah, checkered garters- I miss them). I wonder if it is just a proximity issue and not so much a stress issue. Who knows?

I am interested in this Thai fishing cat thing. What species is this? Are you talking about Prionailurus viverrinus (spelling?)? What sort of in situ program would you consider doing? Captive breeding?

Homer,

I like your idea on mortgages and work- do these stresses increase your desire to mate? LOL. If anything I think the opposite would be true, but then again there is that difference in strategies between having many offspring of poor quality and then having few offspring of good quality. 

No negation here, just passing on some personal opinions. That's what's awesome about science is that anyone could do a study and prove me wrong. An interesting hypothesis was what I was trying to state- not neccesarily wrong in any sense or even unrealistic.

Thanks for everyones thoughts

Have fun, 
Justin


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## Homer (Feb 15, 2004)

andersonii85 said:


> Ryan,
> Homer,
> 
> I like your idea on mortgages and work- do these stresses increase your desire to mate? LOL. If anything I think the opposite would be true, but then again there is that difference in strategies between having many offspring of poor quality and then having few offspring of good quality.
> ...


 :lol: Justin, the same thought popped into my head when I was thinking about this--that's one reason I am not convinced either way. However, to my knowledge, humans do not universally display mating rituals that are often triggered by cortisol. Men just get pot bellies and women add fat in response to elevated cortisol. Although it should be noted that people below the poverty level have substantially more children per capita than people who are in the top 1% of society (please, don't take this as a real argument, there is a heavy dose of sarcasm here).

Regardless, as I pointed out before, I would imagine that there is a threshold level of cortisol that must be achieved in blood serum levels before the adequate receptors are saturated. Again, no studies, just some sketchy memories from endocrinology and some hypotheses built thereon.


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## Ed (Sep 19, 2004)

*stress*

I don't have the references here at home (and am at home for the next couple of weeks) but there are two types of stressors that are considered in relation to animal behavior negative and positive stress. 
From what I remember on corticosteroids (at least in reptiles), elevation causes a lowering of testosterone. In all animals if the level of stress remains constant then the animal "adapts" to the stressor (but only if it remains constant) and the circulating hormone levels return to normal. If the level of stress is increased the symptoms of stress return. 

If I remember correctly the descriptive phrase for animals that are raised together and then fail to breed due to familiarity is the "Coolidge effect". 

Ed


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## bgexotics (Feb 24, 2004)

Oddly enough, we are discussing these kinds of behaviors in my Behavioral Ecology class right now. My professor referred to studies in which amphibians not only bred more under stressful environmental conditions, but laid more eggs when they were exposed to predators. Also young frogs develop more quickly in the presence of predators. ALot of studies have been done on fish related to this. I am going to see if I can find some of the specific studies.


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