I'm currently working on samples of Formica rufa group that where caught on the Italian Alps probably around ten/fifteen years ago. Some of the test tubes show ants preserving a normal colouration, but others have inside completely yellow workers. I'm don't know the exact nature of the preservation fluid they have been put in, I'm sure we are talking about ethanol but I don't know the exact percentage of it. Moreover, a peculiar aromatic smell can be percieved in every test tubes, indipendently by the colours of the samples inside, so I suspect that some addittive was added at the fluid. Since these ant got sampled at the same time and rested in the same substance for the same amount of years, does someone know what could have caused this phenomena?
Dear, can I see the picture of the pigmentation? Contact me by [email protected]
I've observed ants for 8 years, so maybe I can suggest you reason of the differentiated pigmentation.
Hello Enrico; Leaching of pigment is nearly universal in fluid-preserved specimens. Buffering the preservative's pH minimizes decalcification and pigment loss. A commonly used buffer is borax. Here is a manuscript that might help.
Thesis The Effects of Preservation and Conservation Treatments on t...
Best regards, Jim Des Lauriers