Tangled Tubeworm

Image: John Turnbull
Filograna implexa

Worms. Lots and lots of worms. Uncountable hundreds and thousands of worms all hanging out together in a home of their own making.

What would that look like?

Image: Richard Ling

Turns out it looks a bit like coral! And not, say, a really big tunnel. But that's tubeworms for you. Earthworms? Now, that's a different story. If they got together and started digging out a vast housing block for themselves there would probably be cave-ins.

But Tangled Tubeworms, also known as Filigreed Coral Worms, are tubeworms, not earthworms. Which means they're builders, not diggers.

Image: Alfiero Brisotto

Tangled Tubeworms are found all over the world, where they construct their tubes on rocky ground. Each individual is a mere 0.5 cm (0.2 in) long, and builds a tiny, delicate tube to hide in.

Thing is, each colony is made up of hundreds if not thousands of worms and their tubes. The tubes knit and knot and weave around each other to form a craggy outcrop of spiky cauliflower that can be over 30 cm (a foot) across. And it goes all fluffy when the worms extend their feathery tentacles to feed.

Image: Peter Southwood

The worms can reproduce asexually by budding, and it's just as wormish as you could hope. What happens is: a worm divides in two and then each half grows all the bits they're missing. Wasn't that always what was supposed to happen? The front end is the mother, and she builds a little escape hatch in the wall of the tube. Its held in place by a membrane delicate enough for the new youngster to break out.

The young'un is a clone of their parent so a single individual could theoretically found a whole new colony of clones all by itself. But who would do that? Other than corals I mean, and everyone knows corals are basically aliens. Imagine a town with a population of thousands where everyone is you. It's no utopia, is it? You'd probably still find a way of complaining about your neighbour's bad habits while conveniently forgetting that you do exactly the same things.

Image: Peter Southwood

No. Tangled Tubeworms also reproduce the traditional way, and this is how new colonies are formed. There are male worms and female worms. Males make their contribution and then the female broods the larvae until they're ready to be released into the water column.

The larvae drift about for a while but they're gregarious, they like the company of other larvae who are similar to themselves but not exactly the same. So when they settle down on a likely looking rock and begin to construct a tube of their own, they're surrounded by lots of friends doing just the same thing.

It's the better way of doing things. Nice to peek out of your tube and see some new faces, you know?