# Observation on Ventrimaculatus



## steelcube (Mar 17, 2004)

Hi,

People were talking about culling on frognet and I want to also post this here.. 

I have been wondering for some time regarding the way ventrimaculatus cull their unfits in the wild.

Here's why: we know that their tadpoles are cannibal. We also know that they lay tons of eggs at a given time.

So what if, in the wild, these 10-20 eggs were meant to be deposited, to
hatch and eat each other... and out of a pool, only morph one frog at a
given time?

Like a different type of egg feeding...

So in the wild, the most cannibalistic (sp?) tadpoles got to morph and pass
on their genes... 

Any thought?

SB


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## Guest (Nov 2, 2004)

I hypothesize that the social structure of vents allows them to breed more prolifically. Vents do very well in large groups in relatively small areas. There is also the issue of vent tads taking an extremely long time to develop. So, these longer development times expose the tads to a better chance of death from the elements, predators, etc. More tads balances this off.


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## EDs Fly Meat (Apr 29, 2004)

*I agree Steve*

It makes sense to me that vent tads have evolved with this behavior. And it is out of a sense for survial. Five tads in a small container of water are in deep competition to gain a hold of the limited resourses. There just isn't enough food and water to go around. So like birds in a nest, instead of kicking out the smaller bird you eat them. Solves the food problem for a while.  I think that production of multiple eggs are an evolutionary strategy. Some are expected to die, and the more you make the better your chances of passing on your genes. 
I think it also interesting that pirana fish are not aggressive until they find themselves in drier parts of the season. There they swim in very shallow water with dozens of occupants in the same pool. A food item falls in and BOOM! The water boils with aggressive feeding activity. In some way, it is like that. In Siegfried Christmann's book Dendrobatidae he points out some examples of quiquivittatus with bites out of their tails. It is an interesting photo.
But what puzzles me is why some adult frogs insist on dropping newly hatched tads into pools of water occupied by older tadpoles. It would interesting to see if the older tads were progeny of the adults. Or if they adult frog has no idea that the pool is already occupied. Hmmmmmmmmmmmm. Food for thought (Pun intended)
Dave


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## TimStout (Feb 16, 2004)

My guess would be that frog dads would not intentionally deposit more then a few tads per bromeliad funnel although I'm sure it happens. It is also probable that multiple dads have deposited tads into the same funnel especially when there are limited number of deposit sites available. Mathematics apply to successful evolution so are these frogs successful due to their larger numbers of eggs and tads? 
Lets have an evolutionary biologist chime in here!


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## Ed Martin (Mar 25, 2004)

I think that it is a good theory, but wouldn't there be a genetic advantage to being a big tad in the tad eat tad world? So then if the bigger tads did better and fed off the smaller, wouldn't the bigger tads produce bigger frogs????? Or would the advantage be in the tads that hatch earlier, kind of like the statement Dave made about birds in the nest. So I would think that a possible outcome from this theory is that there would be larger tads/frogs or the eggs would hatch sooner than similar species. The first possibility does not seem to be evident, so is there any evidence of the second? 

Joe, you referred to the log time that it takes vents to develop, I do not have them how long does it take? 

ED


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## Guest (Nov 4, 2004)

Too damn long  I have some emerging now, which were laid 6 months ago :shock: 



Ed Martin said:


> I think that it is a good theory, but wouldn't there be a genetic advantage to being a big tad in the tad eat tad world? So then if the bigger tads did better and fed off the smaller, wouldn't the bigger tads produce bigger frogs????? Or would the advantage be in the tads that hatch earlier, kind of like the statement Dave made about birds in the nest. So I would think that a possible outcome from this theory is that there would be larger tads/frogs or the eggs would hatch sooner than similar species. The first possibility does not seem to be evident, so is there any evidence of the second?
> 
> Joe, you referred to the log time that it takes vents to develop, I do not have them how long does it take?
> 
> ED


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## Ed Martin (Mar 25, 2004)

Thanks Joe! 
Ed


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## KeroKero (Jun 13, 2004)

Anybody just let them eat each other and see if they morph faster?

It sounds kinda cruel but if they eat so many of their own kind in the wild they may have adapted to it much like many egg feeders (aka the pumilio people try and raise that stay tiny little tads for well over 6 months etc) that they don't grow as well on other diets. Maybe throw in a lot more meat/protien into their diets instead of the sprulina based fish food type deal a lot of people give their tads. Or, like I said, let them eat each other.

I'd be interested in what people are feeding these guys and their morph times... and if your willing to let nature take its course see if a tadpole diet has a significant change.


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## ETwomey (Jul 22, 2004)

Ed Martin said:


> I think that it is a good theory, but wouldn't there be a genetic advantage to being a big tad in the tad eat tad world? So then if the bigger tads did better and fed off the smaller, wouldn't the bigger tads produce bigger frogs?????


I think you're right, but probably the critical point is that the frogs would morph out larger. This is the most fragile stage, so the bigger the froglet, the sooner it would reach maturity. I don't necessarily think that a big froglet would give rise to big progeny, however. Their big size is most likely due to diet, not so much genes. Getting back to the first post of this thread. I am pretty sure I have read that in some species (D. vanzolinii i think) that adults will deposit TADPOLES in pools containing large tadpoles. They are cannibalistic, so the thought is that it is essentially egg-feeding, except feeding with tadpoles. This would make even more sense with ventrimaculatus, because they are very prolific, and (to my knowledge) do not do egg feeding.

Evan

p.s. I recently had a vent froglet calling at approx. 7 weeks old. Has anyone else had froglets call this young?


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## Guest (Nov 4, 2004)

Vents develop extremely quickly once they morph. Sexual maturity seems to also come very quickly, since they spend so much time morphing. They are an extremely interesting frog and seem to have developed a lot of uncommon characteristics for some reason. Some of these characteristics include a strong propensity towards water (including sleeping under deep water), laying huge clutches in groups under water (upwards of 8-10 frogs in one film canister all going at it at the same time), and their unique mating rituals. Their mating seems to take a noticeably short time, compared to other frogs. I have never seen a male call for any extended time. They usually initiate calling and receive a responce from a female immediately. I wish we had more data on their locality, numbers, and predators!

An yes, they do egg feed.


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## Ryan (Feb 18, 2004)

I wonder since they appear to be carnivorous, if you fed them things like mosquito larvae if they would develop faster? Could the lake of protein be the reason for slow development?


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## Ed Martin (Mar 25, 2004)

Evan, a tad that morphs larger, but not actually a bigger adult makes a lot of sense and would be a lot more difficult to identify in the field. I would think that you would really have to do a captive study because "bigger" froglets might only average a millimeter or so longer. 

Corey... I think that your theory would be a little easier to test, if people were willing to feed the tads in this manner. I would think that first you would have to feed tads to tads and see if they morph faster, then if that is the case, substitute animal protein foods to see if you get similar results. 

Looks like I gotta get some vents! 

Ed


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## Guest (Nov 4, 2004)

KeroKero said:


> Anybody just let them eat each other and see if they morph faster?


My husband-to-be is hankering for some vents, so I suspect vents will come next, and I am willing to try this and what was mentioned in the post above, but I need some data first. Is six months the typical captive morph rate? In the wild, what is the typical body of water like in which the tads are deposited (ie-size in liters, location), and how many tads do the adults normally stick in one spot?


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## rjmarchisi (Feb 16, 2004)

I had some eggs laid July 12th, they went into the water on August 13th and just now one of them has popped out one front leg and its tail is shrinking. They really do take a long time to morph out. I have been feeding them the Tetra Min tablets( which has protein in it ), java moss and almond leaves, one is alot bigger than the other ones, but hasnt popped any front legs yet.

rob


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## Guest (Nov 4, 2004)

Ryan said:


> I wonder since they appear to be carnivorous, if you fed them things like mosquito larvae if they would develop faster? Could the lake of protein be the reason for slow development?


I've not witnessed any noticeable advantages by feeding f/t mosquito larvae aside from them ripping them out of the feeding tongs like it's their last meal. My feeding regime for them has been premium tropical fish flakes, powdered algae and f/t mosq. larvae. Oak leaves are eaten as well and they seem to enjoy munching on the oak leave pieces in between feedings. These pieces of leaves are in the rear vessels from about a week after hatching to the day they emerge. 

-Bill J.


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## andersonii85 (Feb 8, 2004)

I believe that in one of Kyle Summers articles an observation was stated that vents won't deposit tads in heliconia axils if they saw that there were other tadpoles already occupying the axils. I do not believe that they mean to lay these eggs to be eaten, but may be tricked by tads that already occupy the axils. I think egg feeding is accidental- in regards to the parents, but the tadpoles are definately opportunistic. I have accidentally dropped other species of tads in with some of my vents and they will occasionally try to take a nibble before I fish em' out. 

I have found that if I add dried tubifex worms to the feeding regimen that I morph out larger froglets, but this is just observation and not impirical data.

Justin


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## Guest (Nov 17, 2004)

Has anyone tried feeding live brine shrimp? Would they take these as a food source?


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