Beautiful Nudibranchs
I recently spent a couple of weeks at Tjärnö Marine Biological Laboratory where I learned to recognise various groups of marine invertebrates. It was a lot of fun, especially since I have never actually looked closely at live corals or sponges before, such organisms being absent from the dead brackish waters of the Baltic outside Stockholm.
One group that definitely drew the eye were the nudibranchs or sea slugs. Sure, we don’t have the graceful swimming kite-like ones of warmer waters, but you don’t have to be large to display striking colour or form. I took some pictures:
Some nudibranchs feed on hydroids and, somehow, manage to prevent their cnidocytes (the cells containing the stinging nematocysts, used for predation or protection or both) from discharging and utilise them in their own defenses. If anyone knows how they do this, I would love to get an explanation, as the course assistants were unable to answer that question!
ETA: These beauties have now boarded Friday Ark #169.
Friday Ark #169
We’ll post links to sites that have Friday (plus or minus a few days) photos of their chosen animals (photoshops at our discretion and humans only in supporting roles). Watch the Exception category for rocks, beer, coffee cups, and….? Visit all the …
Trackback by Modulator — Friday, December 14, 2007 @ 15:11
Oooh, pretty beasties!
Comment by Martin R — Friday, December 14, 2007 @ 20:33
Because a Day Without Nudibranchs is Like a Day Wi
Don’t ask. Just go look at this
Trackback by The Scratching Post — Friday, December 14, 2007 @ 20:55
Those are so pretty and delicate!
Comment by Sophie — Saturday, December 15, 2007 @ 11:15
Beautiful animals and images.
Comment by DJ — Monday, December 17, 2007 @ 11:55
You asked how nudibranchs are able to take in the cnidocytes into their bodies without them discharging, and the jury is still out on that one. Scientists think that nudibranchs have some sort of direct channel that leads from the mouth, or consumption point, and leads straight to the cerata. The unavoidable problem of touching the cnida seems feasible to the nudibranch, the most popular theory is that nudibranch have some sort of protective lining around the aforementioned “cnidocyte canals”. However, like how hagfish learned to tie themselves in sliding knots, no one really knows.
Comment by Octopusleg — Saturday, January 31, 2009 @ 02:46
Thanks Octopus! It seems like there must be some chemical signal that stops the cnidocyte’s response. Perhaps they have some weird mucus in those canals…
Comment by Felicia Gilljam — Sunday, February 1, 2009 @ 01:06