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.

reefnet
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.