Wednesday 21 December 2011

Christmas Tree Worm

Image: Wikimedia
Do you have a Christmas tree? What colour is it? Blue? Yellow? A gentle cascade of white atop deep reds and mahogany extremities? I sure hope it's not green. Terribly passé...

The Christmas Tree Worm is probably about as beautiful a worm as a worm can be. They may only be about 4 cm (1.6 in) long but they play their part in creating the wondrous, miniature landscapes of the coral reefs they call home.

In fact, they commandeer actual living corals to carve out their abode. These are hard coral, with tough, calcium carbonate skeletons. The Christmas Tree Worm burrows into them for protection, before lining the tube with yet more calcerous secretions from glands along its body. This serves as a defensive fortification and home for life. Their house really is their castle!

Image: Tim Sheerman-Chase via Flickr

The only thing you are ever likely to see of the Christmas Tree Worm is his delightful pair of spiralling Christmas trees. These come in a huge range of colours and are actually modified prostomial appendages.

Image: leafbug via Flickr

The prostomium is the first segment of annelid worms and is just in front of the mouth. Some worms have tentacles and eyes on it, others have scarcely anything there at all. This one has 2, tentacular, festive decorations sprouting from it. The extravagance!

Image: CW Ye via Flickr
It's like an excessively surreal area of the Mongolian steppes!
Better than those Death Worms, anyway.

At least they serve a useful purpose. 2, in fact. These Yuletide plumes serve not only as gills for breathing, but also as the means of capturing tiny food from the water. Hair-like cilia then create a current to pass these crumbs down a groove and into the mouth.

Image: Wikipedia
Orange plug called the operculum.

At the slightest shadow or hint of danger those Christmas trees are dragged down into the hole as the worm uses bristles on the sides of its body to dive to safety. There's even a specially modified tentacle that serves to plug the hole and keep it securely sealed. For Christmas Tree Worms, Christmas trees are for life, not just Christmas.

Probably the most beautiful worm sex you're ever gonna see. Looks like burning incense! Frankincense?

When it comes to reproduction, Christmas Tree Worms still don't want to go anywhere. Males and females just release their sperm and eggs into the water and hope that any resulting larvae will find their own coral to set up home in.

Image: jtu via Flickr

Perhaps you should stick with the usual, green Christmas trees after all? At least they'll only drop those little needles all over the floor.


TexWisGirl said...

wow, they are beautiful!

Joseph JG said...

Yes! It's wonderful that they come in so many colours, too!

Anonymous said...

I was wondering about what kind of Christmas creature you would come up with. This really surprised me, they are so pretty! I don't want to see the rest of the worm (inside the coral), I'm sure it would ruin the picture!

Joseph JG said...

I'm glad I could surprise you! And yes, I'm sure the rest of the worm looks a lot more like a worm!

Crunchy said...

Looks more like a Non-Denominational Holiday Shrubbery Worm to me!

Joseph JG said...

Hahaahahaha! Those worms are way ahead of us!

ben268 said...

I have some of these in my reef thank, they're really quite pretty.

Joseph JG said...

They sure are. Lucky you to have them in your house!

Unknown said...

I am doing a report on them!

Joseph JG said...

Cool! I hope I could help a little!