Logic Behind: Cichlid Eye Coloration

[JK47]

This may be a dumb question but I am not really coming up with anything solid or consistant from bro Google... Is there any behavioral logic or benefit to the species behind the coloration of the eyes in certain cichlids? Let me know if the question does not make sense or is too vague.

Example the genus Uaru:
Uaru Amphiacanthoides both males an females can have orange colored eyes but it is thought only females carry the trait of red eyes. Why?

Uaru Fernandezyepezi is the opposite, it is thought only males carry the red eye traight but females can share both, red being the most common. Why?

 

[JK47]

The same question would apply to isomorphic species as well, why no variations in eye color?

 

[moonstruckmuse]

I'm not really following your questions, but...

I think with the first one, you're asking why both sexes can present a certain colored eye, whereas only one (the females) could pass it on.
My guess for that one is that the orange coloration and the red coloration are not separate genes, but rather different phenotypes. Let's say the genotype EE = red eye phenotype. However, it's a sex linked gene. So, the X chromosome can have E or e. The Y chromosome may have only e, or none at all. Therefore, for females, they can be EE (red), Ee (orange), or ee (normal). Males however, can only be Ee or ee since they're XY.

Of course, this is all speculation.

 

[Modest_Man]

Or it could be a dominance thing. Eye color in cichlids seems to be at least partially self-regulated.

Here's a scientific article on nile tilapia eye color.
http://www.scielo.br/scielo.php?pid=S0100-879X2003001200007&script=sci_arttext&tlng=en

 

[JK47]

I'm not really following your questions, but...

I think with the first one, you're asking why both sexes can present a certain colored eye, whereas only one (the females) could pass it on.
My guess for that one is that the orange coloration and the red coloration are not separate genes, but rather different phenotypes. Let's say the genotype EE = red eye phenotype. However, it's a sex linked gene. So, the X chromosome can have E or e. The Y chromosome may have only e, or none at all. Therefore, for females, they can be EE (red), Ee (orange), or ee (normal). Males however, can only be Ee or ee since they're XY.

Of course, this is all speculation.

In all honesty I don't think I understand my own question here... I at a very basic level understand your what your saying regarding the phenotype, thank you for the explanion on how that could happen. Very interesting.

To put it simply why are there the two different colors at all? i.e. - mate selection? What purpose does that serve when isomorphic species do not share this ability?

 

[peathenster]

Could you clarify the eye color observation - are they red or orange all the time? Many cichlids can change eye colors in seconds.

Do you have pics of red vs. orange eyes?

 

[JK47]

Could you clarify the eye color observation - are they red or orange all the time? Many cichlids can change eye colors in seconds.

Do you have pics of red vs. orange eyes?

I keep only one of the above species (amphiacanoides) and have never seen eye color change. The male always orange and the female always red. I meant from birth, why do some fish of the same species have red and others have orange? Why would nature give the fish two different options to choose from, is there a purpose behind it?