Life's little mysteries

Some interesting links for you:

The Northwest Dragonflier answers the question, "How do dragonflies manage to fly and mate at the same time?" The Foot High Club. (Didn't you always wonder about that?)

What lives in your belly button? More than you would expect. Guest post in Scientific American by Rob Dunn.

And why is this good news? Carl Zimmer, writing for the NY Times, explains.

The project and other studies like it are revealing some of the ways in which our invisible residents shape our lives, from birth to death.

And what is a cormorant doing with a camera? CBC News, Saskatchewan (Canada).

Do worms have teeth? HuffPost Green.

And my own volunteer worm: this little critter has built himself a tube near the glass of the aquarium. He showed up two days ago, and that night the largest crab dug up his home site, right down to the floor. What one destroys, the other builds; the newest tube is longer than the previous one.

Two-tentacled tubeworm, Spiochaetopterus  costarum.

He's much larger than any I've seen feeding so far; the tentacles are about 1/2 inch long.

The first one to show up here, two years ago, was microscopic, too small for the camera; I had to draw it.

I have tentatively identified it as the three-sectioned tubeworm, which lives in this area, but I have my doubts. This little critter coats his tube with grains of sand; the photos of S. costarum show it with a sheath that looks like fabric with the seams (many seams) turned outwards. (Sample photo)

My own links: here's one, eating. And a worm genius.

So, another mystery. If I scrape off the sand, will I find a separate tube inside? Or is the sand glued on too tightly to be removed without killing the worm? I'll have to invent some way of checking that out.