Breeding care, instinct or learning process?

[Graham]

With all this energy spent speculating, why don't we try to come up with a way to test the hypothesis? Is it even possible?

My argument is that environmental conditions will dictate the behavior of the fish over anything learned. If the environment doesn't approximate the natural conditions of an aquatic species, the complete natural behavior won't be observed. So for starters, do we know if female Apistos eat their broods in the wild? Has it ever been documented? If so, with the regularity of that observed in captivity? That would be a good starting point.

The problem with aquatic research in the lab is the need to know many things about the water chemistry and keep them constant over time in a way that conforms to the species' natural environment (unless you're testing their ability to adapt to different environments). If you have access to the necessary instruments, you can go to town. However it's way beyond the means of most all hobbyists...so I guess that leaves us speculating, eh? :wink:

 

[ed seeley]

The experiment I'd love to run is to foster the offspring of captive bred angelfish that have previously ate their eggs and give them to a wild pair of angels that raise their own brood. Apparently this kind of swap is possible as it has been done with discus that don't produce mucous, like pigeon bloods.

If there is a genetic element that has been lost and this is causing the egg eating then the captive bred 'fostered' offspring should still eat their eggs even though they were raised by the wild parents. This would obviously be a major headache to sort and would involve lots of tanks. The only step I've taken down this route so far is having a pair of wild angels that have paired up.....

This would prove (to me anyway!) that the egg eating fish haven't 'lost' the genes for looking after their eggs and babies.

 

[lab]

I think it is both instinct and learned.

I raised some rams from eggs as the male kept eating the wigglers. He would chase the female away from the eggs, but I know the female was parent raised.

A pair from the spawn I raised went on to parent raise in a well planted tank for someone else.

I have had this happen with angels as well. Sometimes it was both of the angels I raised other times they were pair with a non sibling, but we didn't know if the other angel was parent raised or not.

I think you already have your experiment here, Ed, only in reverse. How could there be any learning aspect whatsoever in Nightowls rams raising their broods?

 

[ed seeley]

Originally Posted by nightowl1350
I think it is both instinct and learned.

I raised some rams from eggs as the male kept eating the wigglers. He would chase the female away from the eggs, but I know the female was parent raised.

A pair from the spawn I raised went on to parent raise in a well planted tank for someone else.

I have had this happen with angels as well. Sometimes it was both of the angels I raised other times they were pair with a non sibling, but we didn't know if the other angel was parent raised or not.

I think you already have your experiment here, Ed, only in reverse. How could there be any learning aspect whatsoever in Nightowls rams raising their broods?

Problem is here when one parent is showing parental instinct how do you know that that one parent hasn't passed on genes for 'brooding' to the offspring that raised the babies. You'd really have to use a totally unrelated pair to be sure that the young didn't have any genes that had been passed on from the parent that looked after them.

The opposite of the experiment I talked about, and the one that might show a lot is to take a pair of cichlids that are good parents, might be to raise one brood with the parents and then raise one brood artificially. You would then have to raise the young, pair them off and see if the artificially reared young were good parents or not. Again to have much worth you'd have to raise ALL the offspring and repeat this experiment, or is this basically the experiment you're friend is trying? Of course you might not want to relay that, I remember how competitive research can be!

 

[lab]

Problem is here when one parent is showing parental instinct how do you know that that one parent hasn't passed on genes for 'brooding' to the offspring that raised the babies. You'd really have to use a totally unrelated pair to be sure that the young didn't have any genes that had been passed on from the parent that looked after them.

The opposite of the experiment I talked about, and the one that might show a lot is to take a pair of cichlids that are good parents, might be to raise one brood with the parents and then raise one brood artificially. You would then have to raise the young, pair them off and see if the artificially reared young were good parents or not. Again to have much worth you'd have to raise ALL the offspring and repeat this experiment, or is this basically the experiment you're friend is trying? Of course you might not want to relay that, I remember how competitive research can be!

I'm not sure I understand. As I understood Nightowl, the male parent chased of the female and went on to eat the larvae himself. The female may have been a capable parent raiser, but that was not my point. My point was that none of the offspring were parent raised and still raised their own brood. How could that be if not inherited? If learning is a crucial part of this, then it would basically be lost every time a brood was artificially hatched.

Your outline of an experiment is pretty much what my friend is trying to do. I don't think he minds me telling. He would still be so far ahead any competition by now that it doesn't matter

 

[ed seeley]

Sorry I read that post wrong - I thought he said that he had kept a male with the eggs after he had chased the egg eating female away! Reading again I think you're right.

This does seem to show that fish can raise broods successfully even if they haven't been parent raised themselves.