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Old 07-23-2006, 02:33 AM
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Default Froglet morphing size - parental care vs. external care

In an attempt to slow down the breeding of my Imitators, as well as to observe parental behavior, I allowed the pair to raise 2 tads on their own.

I was amazed at how small the frog cared for by the parents morphed.



Here is an image of one of the last eggs I pulled from the pair - that is approximately the same age - but has a bit more of a tail at this time point.



I have heard/read of others experiencing this as well.

Now - the pair was raising 2 tads at the same time. The tank temps are generally a couple of degrees warmer than the room temps. The parental tad was also raised in a film canister - as opposed to a "Small Round" sized Glad container.

Are those conditions enough to cause a froglet that is nearly 1/3rd the size of an externally raised froglet? The colors on the parental froglet are also not as developed as the external froglet at this time point - even though its tail is nearly completely resorbed.

For those with more experience, especially with field observations - which froglet is more "typical"? By externally raising froglets - are we limiting the natural selection process by controlling more conditions - potentially allowing weaker froglets to survive and potentially reproduce?
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Old 07-23-2006, 05:04 AM
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Oz,

I've seen this multiple times before and I suspect that the key variables are the tadpole rearing 'container' size and food. In the case of small bromeliads, the tadpole size was ultimately defined by the diameter of the brom as shown below...

http://img.photobucket.com/albums/v395/ ... 8_2873.jpg

Imitator tadpole in bromeliad

While I have no doubt that the unfertilized eggs provided by the female make a good diet, I wonder if the food(s) we use to hand rear tads may be more nutritious at some level leading to larging morphing size.

All of the 'small' parental reared tads were perfectly healthy in my experience and ultimately caught up with their hand reared siblings....so I don't think that one was more fit than the other. I have read reports of differences in health (mostly SLS) being seen between parent and hand reared tads though the pattern as to which conditions yields SLS for example varies from person to person.

If anything, we may be 'selecting' for early maturity given that the larger froglets have less growing to do before reaching full size while their smaller siblings require some catch up.

I'm trying to run an experiment now where I have some larger containers in addition to film cannisters in my panguana lamasi viv with the hope that I can evalute the impact of tadpole rearing volume (assuming that egg feeding is similar) on morphing size. So far the parents are ignoring the larger containers and utilizing the film cannisters so I may have to remove a number of the cannisters to see if they will deposit in the larger containers.

Hopefully we'll have some individuals with field experience weigh in with their observations...

Bill
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Old 07-29-2006, 02:05 AM
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With my azureus, I have seen the opposite. I have a pair that keeps hiding eggs from me and hatching them themselves. I haven't gotten around to rebuilding their water feature yet, yet they dropped a couple tads in ana area with about 3/4" of stagnant water. The tadpoles are huge comapred to the ones I am rearing seperately. I just found them this week and added water and started feeding. I am going to leave them and see what happens,
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Old 07-29-2006, 05:59 AM
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I have done the exact same thing, slowed down their breeding by letting them raise them, they pumped out about 25 eggs, which i pulled, then thought OK, slow down. So soon afterward they dropped a couple in a brom and they remain much smaller than the pulled ones. I was feeding them tad bites and some spirolina mix stuff. Mine aren't coming out nearly as big as yours though. what are you feeding them?

P.S. My externally raised frogs can vary quite a bit in size...
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Old 07-29-2006, 03:30 PM
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I am feeding a mixture of foods. I am in the process of adding more variety - but the Imi tad that I have a pic of was receiving mostly a mixture of 50% Flake fish food, 25% spirulina and 25% chlorella. The past 6 weeks or so I have been mixing that food 1:1 with HBH Tadpole bites. I also started adding crushed Betta bites in the past month. When the tadpoles are very young (first 2 weeks or so) - I start them on Sera Micron.

Are you raising the tads individually or in a group? What size container?
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Old 07-29-2006, 05:17 PM
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Some thoughts on this topic...
With darts you have to take in account their evolutionary history, in at least 3 groups. The first of them has female parental care, the second has biparental care (at least in some species) and the plesiomorphic male parental care.

* obligatory egg feeders: the size of the froglets is bigger when the parents feed them succesfully. In frogs who are often bad parents in small enclosures, the erratic feeding frequence give as result very small and weak froglets or no metamorphs at all. Anyone who has tried the egg yolk method can see that the froglets produced in that way are really small!

* Non mandatory egg feeders
The size of the parent raised froglets its smaller than the artificial raised, mostly because the frequency of feeding and water volume. Small water volumes in wild makes a tadpole prone to dissecation and death, so their metabolic machine work faster, to be able to develop theirselves before the phytotelmata goes dry. As they dont have specializated stomach sacs, they need to be feeded often, who is more easily done in artificial rearing systems.

* Other groups (tinc group, Epis)
the size at metamorph will depend of many factors:
temperature: too high temperature also makes the metabolism faster and stress them = smaller froglets (and maybe SLS?)
number of tadpoles in the container: As this groups arent small phytotelmata specifics, tadpoles are less canibalistic (more food resources and water available). However, crowding tadpoles, as in other tadpoles generate behavioral inhibitions, with fast growing tadpoles and slow growing tadpoles, who often die and are canibalizated by their bigger brothers.
* Water volume: they are more sensible to small water containers than the 2 other groups, and in small containers will grow faster, reaching smaller sizes.

Of course, there are a lot of more factors in this topic, we shouldnt forget that some tads are mosquito feeders, and simply will grow faster with the right diet.
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Old 07-30-2006, 03:12 AM
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thats about the same thing i have been feeding mine, Rozdaboff, the fishfood, spiro. and chlor., along w/ tad bites too. I am raising them individually and the containers being Glad sandwich container, when the front legs pop, i move them to the tilted shoebox to climb out of.
i took a good look today at all of them and some tads are huge w/ small rear legs and some have all four legs and are quite a bit smaller in size.
so it seems to me that they have their own variance even though i give them all the same conditions, the 6 that are out all seem very fat and healthy, feeding well on springtail and flies.
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Old 07-30-2006, 07:55 AM
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That's an interesting observation. It's a rather small sample to generalize from, but it would be an interesting evolutionary strategy to have that degree of developmental variation within a frog's offspring. The quick developers would be advantageous under certain environmental conditions, such as when phytotelmata are likely to dry up quickly, whereas the later developers morph larger and might be hardier/better able to find food, etc. Sort of covering all the bases.
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