Bispira "aurora"

[c est ma]

In May, I found myself needing something to fill out my LiveAquaria order to reach their minimum amount. I chose a Bispira feather duster, yellow morph.

 

A few days after receiving it, my daughter asked, "Is it just me, or is it changing colors?" I looked closer and realized that, in addition to its rotational movements, it was, in fact changing color! A greenish color arose from the center of the worm, propagated outward, and was replaced by the normal light yellow coloration. The green color moved around the worm in counterclockwise fashion like a stadium of people doing the wave, originating in the center and proceeding toward the perimeter.

 

I'm sure i'm not the first to notice this! Nevertheless, I thought it was pretty cool. To my mind, it reminded me of nothing so much as watching the aurora borealis.

 

I got some pics that, while not great, hopefully capture the phenomenon.

 

This pic, and the pic following, show the green color moving from side to side:

 

 

 

My 3.1 megapixel digicam vids do not translate well after uploading, but hopefully enough will survive in the following two short vids to show the color-changing phenomenon:

 

http://video.google.com/videoplay?docid=8868553224682683601

 

http://video.google.com/videoplay?docid=-7568468963670744121

 

It occurred to me that the color change might be due to the changing position of the "pinnules"--or whatever the fine hairs of the worm's tentacle might be called. I managed to get the following macros of the worm's rays in yellow and green mode:

 

 

 

I wonder why it does this?

 

--Diane

[Mudfish]

That is INCREDIBLY cool!

 

I won't tell you what it reminds me of; leave it to say that I am a child of the 60s....

[c est ma]

Far out. Me too.

[jimbro]

That is awesome! I'd love to get one, but I think my sixline might enjoy it more than me (he likes to pick pieces off the feather duster I have, so now it only opens at night).

 

I think you're right on how it changes color, similar to how ctenophores do it, by refracting light with their cilia (or whatever). That's what I was thinkin before I saw the end of your post. Pretty cool no matter how it's done.

 

Why it does it is indeed the question.