Some 20 years ago I was out on my deck and I found this all metallic green fly that was smaller than normal flies. Even the head was green. Not quite the same, but similar to the picture.

I caught this fly inside a little plastic cup with a lid. I wanted to look at it up close. Then I saw a little tiny jumping spider a little bit bigger than the fly. I lifted the lid slightly and coaxed the jumping spider inside the cup as well. So now I had this little jumper hunting this cool green fly. I set it down and did something else.

Later I came back and the spider had the fly. He was having green fly snack. I left it alone again. When I came back I was absolutely astonished by what I saw. The metallic green fly was dead on the bottom of the cup. But it was now a metallic blue color! What?! Then I realized the loss of moisture probably caused the skin/shell to contract changing the wavelength being reflected to a blue color.

This made me wonder. How many entomologists have specimens what are labeled "green fly", but the specimens are blue?

Is this an early example of web devs (spiders) making CSS changes to nature?