While identifying the Queen Alexandra's Sulpur butterflies in our backyard, we read that they are also sometimes called UV Sulphur butterflies. The male butterflies reflect UV light to attract females - or something like that. We didn't fully understand everything we read, but we wanted to check it out.
I made a quick butterfly net out of a hanger, and some netting, that came around our oranges, for the children...
...and sent them on a butterfly hunt.
Once we captured a specimen (and by we, I mean me - much to the amusement of our neighbors, I'm sure), we placed it into an empty fish bowl...
...so we could shine a UV flashlight onto it, in a dark room. It sort of glowed, but not in anyway that was impressive, so I'm thinking there's more to it, than we were seeing or understanding. Still, it was worth a try.
After we released our butterfly back into the wild, and watched it fly away, stunned but unharmed...
...we decided to take a look at one of the dandelions it was frequenting. This time our UV light revealed something interesting. The florets on the outer edge of the flower turned a light pink, while the center of the dandelion remained dark yellow. After a little more research we found out this is called a nectar guide.
Butterflies, like bees, and a number of other insects, don't see the color red, but do see some UV light. When viewed under a UV light, many flowers have patterns that indicate nectar, and draw insects in like a bullseye.
We won't be looking at dandelions the same way again. Who knew there were so many fascinating scientific discoveries waiting in our backyard?
Wikipedia - "Ultraviolet Communication In Butterflies" and "Colias Alexandra"
Boston University - "Ultraviolet Patterns in Flowers, or Flowers as Viewed by Insects" by Richard B. Primack. This is a good one to read, if you're wondering how scientists know that insects can see UV light and not red.
PBS Kids - Fetch!: season 4, episode 13, "Is it a Bird? Is it a Plane? It's...Ruffmanman!"