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Structural mutations and psittacines

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Recio
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Structural mutations and psittacines

Post by Recio » Wed Mar 06, 2013 3:42 pm

Hi everybody,

There is evidence to consider that a wild green IRN has a different feather structure in the head than in the rest of the body. Some facts:

1. The head colour of a young blue IRN seems to change of colour (hue) and brigthness (saturation) depending on the angle sun-bird-observer. This is something really particular to the head feathers and not found (or to a much lesser extent) in other body regions.

2. The head of DF dominant Pied Blue (Chriss Whipps, page 13 of Deon's book) appears as a light blue ... in a bird whithout peripheral melanocytes (at least in theory)... and, thus, without melanin. One possibility to explain this is that the blue colour is produced as a structural colour without any pigment ... so it would mean that the head feathers are somehow different of the body feathers which remain white.

3. The head of a Blue Cinnamon adult male show a blue colour while the rest of the body colour is mainly blue-grey. Since there are not psittacins, and the only melanin present in the whole bird is brown melanin, the only thing able to explain this specific colour is a different feather structure.

We also know that the only pigments in IRN able to produce fluorescence under uv light are psittacins, and we know that the fluorescence we can see is different on the wings coverts (it is brillant and flashing) than in the head (I called it deep yellow). For a long time (several months) I have been thinking that this difference in expression was due to a different type of psittacine but now I am considering the possibility that it is the same type of psittacine but we see it differently due to the feather structure, which probably it is not the same in the head than in the rest of the body, as explained above.

If structural mutations are able to change the perception of the reflected fluorescence under uv ligth it could explain Willi's results with Green series Emeralds being fluorescents (typical fluorescence of Emeralds) and Blue series Emeralds without this typical fluorescence ... pointing to Emerald as a structural mutation (of course those are just ideas for brain storming ...).

If these considerations are rigth we should study every structural mutation in the green series under normal and under uv ligth. If the study is restricted to the blue series we will miss a lot of information. Probably the perception of psittacins under uv is dependent on feather structure. Has anybody look at grey green, dark greens, violet greens, deep greens, misty greens, ... under uv? Maybe it could be easier to identify the differences between SA deep and other structural mutations in this way than just looking at it expression in blue series birds.

Regards

Recio

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sheyd
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Re: Structural mutations and psittacines

Post by sheyd » Wed Mar 06, 2013 8:20 pm

Would be interesting for sure- I'm guessing this would be limited to cocks only?

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prodigy
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Re: Structural mutations and psittacines

Post by prodigy » Wed Mar 06, 2013 10:56 pm

Hi Recio,

I have spent allot of time under the UV with green series birds for obvious reasons and have noticed huge differences in fluorescence.

It is my opinion that florescence has nothing to do with the color of the bird and everything to do with the structural mutation.

I have also observed that a single structural mutation might not influence florescence but that combinations of two structural mutation some times then allow for florescence.

For example:

A grey green show no florescence under the UV

A SA Deep grey green shows florescence under the UV

Or am I just stating the obvious here?

Regards,

Peter

smick
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Re: Structural mutations and psittacines

Post by smick » Thu Mar 07, 2013 2:06 am

Although not about ringnecks but I watched a doco studying colour mutations and uv floresence in budgies. The. Forehead unbarred region on cocks showed the most uv floresence followed by cheek dots, the wild type showed the most uv floresence and when given the choice hens would pick cocks with the most uv floresence. They speculated that birds can see in the uv spectrum and they would see birds with the best uv floresence as more attractive. In indian ringnecks do the forehead, crown area's show the highest uv floresence And if yes I would be inclined to agree that head feathers have a different structure from body feathers. Do indian hens also prefer cocks with the strongest uv floresence when given the choice, this may explain why some cocks are hard to pair up. Has anybody got a cock that shows poor uv floresence and has been hard to pair up?,thanks smick.

Recio
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Re: Structural mutations and psittacines

Post by Recio » Thu Mar 07, 2013 5:54 am

Chocobo wrote:Would be interesting for sure- I'm guessing this would be limited to cocks only?
Fluorescence depends on the presence of some specific yellow psittacines which are present in both males and females, so the observations can be made in both sexes. You just need that they express yellow psittacines (red psittacins and melanin are not fluorescents). Nevertheless it is true that males express a higher amount of fluorescence than females, mainly in the head.

Recio

Recio
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Re: Structural mutations and psittacines

Post by Recio » Thu Mar 07, 2013 6:22 am

prodigy wrote:Hi Recio,

I have spent allot of time under the UV with green series birds for obvious reasons and have noticed huge differences in fluorescence.

It is my opinion that florescence has nothing to do with the color of the bird and everything to do with the structural mutation.

I have also observed that a single structural mutation might not influence florescence but that combinations of two structural mutation some times then allow for florescence.

For example:

A grey green show no florescence under the UV

A SA Deep grey green shows florescence under the UV

Or am I just stating the obvious here?

Regards,

Peter
Hi Peter,

Those are really very interesting observations. We know for sure that the perception of melanin as grey, blue, cobalt, violet, ... depends on the feather structure (mainly the spongy zone) but almost nothing has been reported on the perception of psittacins related to different feather structures.

Fluorescence is undoubtelly related to the bird's colour and if the bird does not own psittacins you will never get fluorescence under uv. But if the bird owns yellow psittacins the way they are perceived is probably highly dependant on the feather structure.

We know that the presence of melanin can disturb uv reflexion because a higher amount of uv will be absorbed by melanin, and thus, to perform these studies in the best conditions we should study birds lacking melanin: Ex: Dark SL-ino, Violet SL-ino, ... Those birds are extremely rare, so as a first approach we should study just Dark green, Violet green, ...

You say that a Grey green bird does not show fluorescence under uv. Grey is known to destroy the spongy zone and this is the reason that we can not get any blue/cobalt/violet ... colour when Grey is present (here there is matter for another discussion). If your observation is rigth we can say that probably grey also alters the cortex structure, since psittacins are deposited at this level. This is something revolutionary since in this case Grey could be also used to check mutations suppossed to act on the feather cortex. Ex: the brigthnes of Misty is thougth to be due to an action on the feather cortex. What would happen in a combo Grey Misty? Would brigthness be lost?
Tonight I will have a look under uv to my Grey Green Cleartail adult male. He does not own melanin in the head and I would be able to check for the interaction of psittacins and feather structure (Grey) without the disturbing effect of melanin.

If Deep can partially reverse the effect of Grey on fluorescence this would be an argument for considering Deep as a structural mutation but acting different than Grey and producing an epistatic phenomenon in the combo. If this effect of Deep is overrided by the presence of Grey in the homozygous form (DF Grey) this would be an argument to consider that Grey is also an incomplete dominant mutation like Dark or Violet.

Regards

Recio

Recio
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Re: Structural mutations and psittacines

Post by Recio » Thu Mar 07, 2013 6:28 am

molossus wrote:Recio,
Does the Misty mutation alter flouresence?
if yes ... is it now a structural mutation?
if no ... what is it that I see in the feather hue in changing position or sunlight?
Hi Lee,

Our minds are synchronized. My guess: Misty is suppossed to act on the cortex by changing its structure. We know that psittacins are deposited in the cortex. It seems that the cortex structure alters the characteristics of the reflected ligth. All together it makes me think that probably Misty is able to change the perceived uv induced fluorescence but I do not know any study about this subject. If I am rigth you have the birds to do it ....

If confirmed it would add consistency to the hypothesis of Misty as a structural mutation. Maybe Misty shows a double optic phenomenon : iridescence and an altered fluorescence both depending on a change in feather structure. We'll see.

Regards

Recio

Recio
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Re: Structural mutations and psittacines

Post by Recio » Thu Mar 07, 2013 7:52 am

smick wrote:Although not about ringnecks but I watched a doco studying colour mutations and uv floresence in budgies. The. Forehead unbarred region on cocks showed the most uv floresence followed by cheek dots, the wild type showed the most uv floresence and when given the choice hens would pick cocks with the most uv floresence. They speculated that birds can see in the uv spectrum and they would see birds with the best uv floresence as more attractive. In indian ringnecks do the forehead, crown area's show the highest uv floresence And if yes I would be inclined to agree that head feathers have a different structure from body feathers. Do indian hens also prefer cocks with the strongest uv floresence when given the choice, this may explain why some cocks are hard to pair up. Has anybody got a cock that shows poor uv floresence and has been hard to pair up?,thanks smick.
Hi Smick,

Birds can see in the uv range ... so they can see uv reflectance. IRN can see other IRN differently than we mammals do. For us, mammals and possible predators, the wild bird appears as homogeneous green and so it is very hard to see him when he is on the green or on trees, and he can scape us and survive. How can the bird manage to signal his presence to other possible partners and, at the same time, avoid detection by predators (mammals)? He can do it through his ability to signalling and see in the uv range.

Studies in budgies have shown that mate choice preferences depend on uv reflectance, and not on uv induced fluorescence.

Do not mistake uv reflectance (reflected ligth in the uv range: lambda < 400 nm and only visible to birds) and uv fluorescence which is visible to birds as well as to mammals. Nevertheless uv fluorescence is of very low intensity and is only detectable to our eyes in specific conditions (darkness, uv source, ...). During daytime the contribution of natural fluorescence to the "total colour amount" of the bird is minimal, and other phenomena such as iridescence, normal reflection, constructive interference, ... and uv reflection (just for birds) seem to be more important.

Regards

Recio

PS: Let's call "total colour amount" to the totality of factors acting in what our eyes perceive, not only colour (hue, saturation, brigth) but also iridescence, ...

Recio
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Re: Structural mutations and psittacines

Post by Recio » Thu Mar 07, 2013 11:47 am

Hi,

I have just look at my Grey Green Cleartail adult male (3 years) and I am absolutelly sure that Grey does not change uv induced fluorescence either in melanin free areas (head) or throughout the wings and back area. Could you please Peter verify your observations on Grey Green birds?

Regards

Recio

Johan S
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Re: Structural mutations and psittacines

Post by Johan S » Fri Mar 08, 2013 12:13 am

molossus wrote:I prefer to have a second pair of eyes so this will have to wait till April when Johan comes over.
Do you have my wife's permission to make statements like that??? :lol:
Recio wrote:I have just look at my Grey Green Cleartail adult male (3 years) and I am absolutelly sure that Grey does not change uv induced fluorescence either in melanin free areas (head) or throughout the wings and back area.
I have observed the same with the Mauve TurquoiseBlue cock I had with me last season. There was a slight reduction in UV induced fluorescence when compared to the green ino cock I had, but that is easily explained by considering I was comparing a parblue with a green series bird.

Also, seeing as we are talking about fluorescence and heads, two pics to show under normal lighting what to look for. Notice that the front part of the lutino cock's head is a very bright, rich yellow. This is the fluorescent region and when you look at birds under the right light, you can see it with the normal eye (as that bright colour). In the same pictures are a dark green fallow cock (in molt, so not very good looking) where a melanin reduction occurs, but still the fluorescent region in the head is very visible (no melanin left). I have not studied the bird under UV light (yet), but the coverts will be affected by a structural mutation and a melanin reduction (50% region, although this line might be a bit more). Even in this picture, to me it seems as if it will be fluorescent.

Image
Image

Recio
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Re: Structural mutations and psittacines

Post by Recio » Mon Mar 11, 2013 2:35 pm

Hi everybody,

We know for sure that Grey and Dark do not affect psittacins expression in the feather cortex. What about Violet? Deep? Misty? ... any observations under uv?

Regards

Recio

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