Examination of colour?

[Morgan]

I wanted to open up a topic about the actual physical colour in shrimp and find out what we know. I don't have any answers here, just questions, but hopefully it will start a discussion that might throw up some info or at least get us started.

 

Years ago I was interested in Bettas, which have been bred to extremes, examined, dissected and generally studied for years now. One of the things I found particularly interesting was that the colours had been fairly clearly identified and that there were essentially four colour layers in a Betta. The layers were yellow layer (bottom layer), black layer, red layer and iridescent layer (top layer). The iridescent layer controls the blue colours, and comes in turquoise, steel and royal blue. The expression of traits in each of these layers and the way they overlay each other gives a phenomenal amount of variation in colour, and of course gives serious Betta breeders some valuable info about what to cull or introduce. Eg, anyone going for a yellow type should be culling anything with red because it will 'cover' the yellow.

 

So that gets me thinking about shrimp. Everyone's breeding for particular colour expression, but has anyone with a microscope sat down and tried to figure out where the colour is and how it's showing up? Do we know whether the pigment is in one layer or several? Where does the pigment sit exactly? What do we know about the genetics of colour expression?

[jayc]

I think the colour is in one layer. The colour is not on the shell, else you'd see the colour on the discarded shell every time the shrimp moults. The easiest method of examining a shrimp is to peel a cooked prawn instead. Not only is it bigger and easier to handle, Christmas is coming up so there will be plenty of prawns around to examine. ;p

[Squiggle]

I have done a bit of research into the colour of shrimp & the history of the different colours in cherries, i.e. Where they came from & how the different colours came about, & I have found that there are two basic colour areas for cherries(I'd have to do more research to be sure of Caridina sp.) They basically have a flesh colour & a shell colour pigment. The flesh colour pigment is evident in lower grade yellows, sunkist, chocolates, blacks & greens. The higher grade "painted fire" versions of all these have more of a shell based colour pigment, which is evident when looking at the thick glossy shells of these varieties.

In saying this, I completely understand what jayc was saying about the colour not being in the shell & I'm lead to believe that it may be like our skin & when we get sunburn, when we peel the skin that comes off is white but the skin left underneath is still quite red. I realise this is quite different to the shell of a shrimp but you get where I'm coming from.

[Morgan]

Sorry Jayc, I think I didn't explain what I was trying to very well in that post. The colour layers in a Betta would look like one layer to the naked eye, it would take serious examination under a microscope to see where the differences lie, and I was wondering if anyone had done this yet with shrimp? I think you're right that it can't be the outer layer of shell, moulting is always clear/whitish.

 

Fascinating stuff Squiggle, are the flesh colour and the shell colour always the same that you've seen? If not it could lead in some curious directions.

 

I see what you're saying about the similarity to colour in human skin, and it makes sense. Human skin colour varies depending on the thickness of the skin in different parts of the body (how much colour from the tissue underneath shows through), and whether melanin (sun tan) has been activated.

 

I saw this web page:

http://theconversation.com/how-do-chameleons-and-other-creatures-change-colour-13842

 

Which is pretty simplistic but it did make me wonder about what technique our native Chameleon shrimp are using to change colour and what that might mean for potential line breeding of colour.

 

I'll keep researching and see what's out there. Hopefully there might be some research articles somewhere?

[Squiggle]

In cherry shrimp it is always the same colour but I don't think so in Caridina sp. i.e. Golden bees for example can have light cream coloured shell with a dark orange coloured flesh underneath & vice versa, darker orange shell with a light, almost clear, flesh colour.