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Odonata
May 8, 2011 10:17:18 GMT -8
Post by kiarashheshmati on May 8, 2011 10:17:18 GMT -8
Post a picture of your odonata collection, i havn t seen too much around the internet.
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Odonata
May 10, 2011 1:16:45 GMT -8
Post by dragonflyer on May 10, 2011 1:16:45 GMT -8
Yes, you're right, Dragonfly-collections seem to be rare. Here are some of my favourite specimens. Zenithoptera lanei & Z. fasciata from South America and on the right Palpopleura portia from Africa.
Regards, Nic
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Odonata
May 12, 2011 5:49:55 GMT -8
Post by kiarashheshmati on May 12, 2011 5:49:55 GMT -8
Looks beautiful, do you think there is any color loss with these sepcimens, i feel Odonata loose color, or maybe its just me?
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Odonata
May 12, 2011 7:18:59 GMT -8
Post by dragonflyer on May 12, 2011 7:18:59 GMT -8
That's right. I don't think that it is possible to preserve the bright colours (red, blue, green, yellow, etc.) of living Odonata's body and eyes. But some color can be conserved when treating the specimens with acetone and let them quickly dry, e.g. in an oven at low temperature (~40° Celsius). Yellow can be preserved very well with this method. The best method might be freeze-drying, but it is seldom accessable.
But it does also depend of the kind of colour. Wing colours and (blue) pruinosed species should not be treaten with heat or chemicals. Their colour often depends on structural (waxy) layers. Those won't disappear in dead specimens (look at picture above). Metallic colours do not disappear, too.
It would be nice to see some pictures of other dragonflies!!!
Regards, Nic
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Odonata
May 13, 2011 8:52:50 GMT -8
Post by starlightcriminal on May 13, 2011 8:52:50 GMT -8
Acetone treatment is used to "fix" the proteinaceous pigments which will undergo proteolysis as the insect decays if they are not treated. Pruinosity is lost because the surface is disrupted- correct me if I am wrong, but I thought pruinose= powdery surface, not necessarily blue. The metallic colors are refractory so they stay, just like with butterfly wings. True pigments are much more ephemeral and therefor have to have special consideration when deciding how to preserve best. I don't do it much, but there are differences in color quality depending on which type of treatment you use, how long, etc.
I have not trouble with blue or green coloration and acetone fixation. I inject a small amount into the body prior to immersion in acetone (usually for a day or two total). The acetone itself will completely dry the specimen so be sure it is in the position you want as they are very brittle after this. No need for heat drying in my experience. I use anhydrous acetone and get the best results (look for molecular grade acetone). Would be interested to know of alternative chemicals if anyone has any experience. Always experimenting.
You know those "body" exhibits with the preserved human remains looking life-like and rather creepy? They are done in a similar fashion- extensive acetone washes and latex/silicone injections to preserve the volumetric aspects.
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Odonata
May 13, 2011 8:53:35 GMT -8
Post by starlightcriminal on May 13, 2011 8:53:35 GMT -8
BTW, the eyes will get opaque. Haven't found anyway around that. But the colors on the body keep very well.
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Odonata
May 13, 2011 14:49:01 GMT -8
Post by lucanidae25 on May 13, 2011 14:49:01 GMT -8
If anyone finds their specimens are getting too brittle after immersion in acetone, uses only 2%-3% water in the acetone to stop the specimens from drying out and you'll be still able to pin your specimens afterward. I use this to preserve the yellow with Buprestidae here in Australia.
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Odonata
May 13, 2011 17:05:44 GMT -8
Post by starlightcriminal on May 13, 2011 17:05:44 GMT -8
Thanks for the tip.
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Odonata
May 13, 2011 18:57:19 GMT -8
Post by kiarashheshmati on May 13, 2011 18:57:19 GMT -8
@starlightcimminal The Acetone technique that you use has worked fairly well? I would love to keep all the colors, i like to collect species from all Orders, it would be great to keep these colors becasue without color, they lose their significance.
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Odonata
May 17, 2011 7:48:58 GMT -8
Post by starlightcriminal on May 17, 2011 7:48:58 GMT -8
It should as far as I know- it's chemically sound reasoning and works in my experience. I haven't tried on everything and sometimes it does require injection for some of the larger bodied specimens, but it works very well on Odonata and Coleoptera, also some Hemiptera and Diptera. It's a matter of permanently "fixing" the bonds of the proteins that make up each pigment, which acetone is excellent for. It works by virtue of its ability to rapidly dehydrate in part so it's likely that some of the other desiccants that are non-denaturing would also work. Pruinosity is another issue because acetone treatment would disrupt the fine surface structure that creates the "powdery" look, as would most other liquids. Freeze drying might work but in general freezing and thawing only cause shearing of the pigment peptides (think of when you drop an ice cube into a glass of water and it pops and cracks- same thing happens to cells, proteins, everything else when it freezes and thaws which is a very easy way to ruin them) so I would be hesitant to recommend it unless you are certain the specimen is completely dried before you try to remove it, and then I would only remove it in a vacuum until the temperature of the specimen can equilibrate with the ambient temperature so it doesn't immediately begin to rehydrate with atmospheric moisture.
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