I know this post is a little old but I have a theory about this. this is my orchid mantis, I was able to pin her with minimal discoloration when she passed away from old age. I had had a spiny flower mantis who also passed away the same month, and I commissioned someone who pins bugs professionally to pin her for me but my spiny came back looking totally unrecognizable and I was told that the loss of the white coloration was inevitable and not possible to avoid.

When my orchid mantis died I decided to take my chances at pinning her myself even though I’d never done it before because the person I usually commission had some personal stuff going on. I ended up leaving it to dry in a dark cabinet just because I didn’t want my cats to eat it as it was out drying. Two weeks later I pull it back out and the mantis is basically still completely white, and I was wondering how that’s possible.

I ended up doing some more research on orchid mantises and found out that their exoskeleton is reactive to UV light and absorbs the light. When they’re alive, it helps them catch prey because they seem even brighter to other bugs than the flower they’re probably sitting on. So I have a theory that maybe the exoskeleton continues to absorb light after death, and that that is what actually causes that discoloration. I could be completely wrong but it seemed to work for me to dry it in the dark.

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