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Post by jamesd on Sept 23, 2011 17:16:19 GMT -8
Has anyone ever noticed beetles that fade after a while?
With some Coccinellidae that I have, I've noticed that their colour fades after several months.
Is there anything that can prevent this?
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Post by prillbug2 on Sept 23, 2011 19:14:21 GMT -8
No, there's nothing outside of photography that you can do about it. They are not structural colors, they are pigments. Freezing might help, but who wants to store the entire collection in the freezer?
Jeff Prill
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Post by jamesd on Sept 24, 2011 0:09:10 GMT -8
Aww. Well thanks anyway.
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Post by lucanidae25 on Sept 24, 2011 1:03:37 GMT -8
Which colour is fading? Is it the yellow?
If it's the yellow or white turning brown, you can try acetones with only 2-3% water but keep changing the acetone untill it's clear, only then I will take it out and dry them or dry them very slowly in the fridge for 1-2 months
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Post by jamesd on Sept 24, 2011 22:45:10 GMT -8
Yeah, the orange turns to an orange/brown colour. Sounds like a bit of work though.
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Post by lucanidae25 on Sept 25, 2011 17:26:41 GMT -8
It's the only two way that I know will be able to keep the yellow or white in beetles. Same thing with Dynastes going black, it's the body fat that causes to change the yellow to brown. You can dissolve the fat in acetones or only dry in low temperature to stop the fat from becoming liquid. I used this method to dry all my buprestidae from OZ.
There is one other way and that's to keep the beetles in the fridge alive, so that the beetles can burned up all their body fat slowly and die from starvation. You would still need to dry them in the fridge.
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Post by starlightcriminal on Sept 26, 2011 9:54:40 GMT -8
Yeah, you need to "fix" the proteins that give it the color, otherwise they denature as endogenous proteases go to work. Cool works because it inhibits protease enzymatic activity. Once they are dry the proteases will also not work but getting something completely "freeze" dried is not that easy and just a little amount of water will be enough for the enzyme to become active again when they warm. One function of freezing which is tricky is that the freezing also preserves the proteolytic enzymes that are cleaving pigment proteins at room temperature, so when the specimens warm back up so does the enzyme. Best way to stop enzyme activity is to be completely dry or to heat- obviously heating also denatures protein so that isn't a good option. There are a number of specialized commercial products for fixing proteins (protein fixing, probably not called color fixers or something similar, it would be used outside of the normal purposes which are fixing things for slides and such most often) if you have something that you consider valuable enough to buy some.
Another thing which I have not heard being used but recently thought would be using a protease inhibitor of some type, such as PMSF or DFP, in an acetone wash or some other saturating bath. Serine protease inhibitors are more general and stop most proteolytic enzymes but it might require a combination to cover them all. I couldn't say which proteases are present in a dead insects body. Be aware that some inhibitors can be very dangerous if they get into your bloodstream so check them out thoroughly before using and take proper precautions (gloves, eyes, protect your mucous membranes, etc.) as required.
I use acetone personally but I don't have anything that sensitive or valuable and don't do it much. I might try the inhibitor method just out of curiosity the next time I have something that I wouldn't mind experimenting on, in theory it should do the trick. If it works, I will of course report back. Maybe someone else has already thought of it anyway, it would be worth investigating.
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Post by lucanidae25 on Sept 26, 2011 15:00:00 GMT -8
Inhibitor interesting!!!! It's expensive enough for me to buy my 30L of acetone a year to fix on the bups from OZ here. 80% of Buprestidae and some of the Cetoniidae would need some kind of fixing for the yollow. So I just stop collecting them here all together. What I do find is even though I fix the yellow with acetone. After 5-10 years the specimens would still slowly turning a light brown over time and I need to acetone them again.
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Post by arrowhead on Sept 26, 2011 21:55:18 GMT -8
Hi. I'm still new to the science but have noticed not all tityuses and grantis go black. I have no idea why. I have observed living specimens go back and forth, seemingly due to air exposure. I caught a Pelidnota this year, a species famous for posthumous color changes but this one sported a dark band across the lower end of it's elytra while still alive. I've seen them change to a darker copper color after death, whether they were allowed to live their life out or frozen or acetoned. There's a
'potato bug" from the Chrysomelia family, C. Scripta i believe, that does the same.
Cheers,
Arrowhead
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Post by lucanidae25 on Sept 26, 2011 22:11:33 GMT -8
If the tityuses and grantis have already dried and gone black, the only way to get the colour back is to use acetone but if you have any live specimens try starving them in the fridge and dry them only in the fridge, not the frozer part of the fridge. That would be the cheapest way to keep the colours. Or just do some different experiments with any of them to see which one you would prefer.
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Post by Rev. Redmond Farrier on Sept 26, 2011 22:24:49 GMT -8
Thanks to this post and a bit of acetone, my female tityus has her spots back  Thank you! |
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Post by starlightcriminal on Sept 27, 2011 5:08:30 GMT -8
I noticed that about D. tityus too, it's very odd. And it does happen while they are alive, back and forth for no apparent reason that I can see. I never did anything to get a live specimens color back, it just would. I had a one die that turned black right away but I found it relatively shortly after death and spread it right away and the color came back without treatment. I have pondered this a lot, anyone know the physiologic reason this happens with live specimens?
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Post by lucanidae25 on Sept 27, 2011 5:55:54 GMT -8
I think might be something to with water content and humidity. I noted the same thing with all live Allotopus sp too, it goes in and out of black and gold. I also noted if I put the Allotopus inside a container, it will go black but once I takes it out of the container it will go back to gold again once it drys a bit.
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Post by 58chevy on Sept 27, 2011 10:54:24 GMT -8
Acetone works great for restoring color in D. tityus. I've used it many times. I tried it on Pelidnota punctata and it just made them darker. If anyone tries enzyme inhibitors, let us know the results.
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Post by jamesd on Oct 3, 2011 21:13:12 GMT -8
How is acetone applied to the specimen? Do you dip it in the acetone, soak it in acetone for hours, drip acetone on it?
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Thank you!
