Cannibalism? with Janolus cristatus
March 27, 2007
From: Mat Vestjens
Hello Bill,
Two weeks ago I observed something very interesting. I found a strangely curled specimen of Janolus cristatus. At first I could not tell head from tail and tried to make some shots to sort it out later (picture 1). Then the larger part of the entanglement moved on and a smaller part stayed in position (picture 2). My first thought was that a small and a big specimen had been mating, but after looking closely, the smaller part did not have a head (picture 3). Is cannibalism known from J. cristatus? As far as I know, they feed on bryozoans.
Locality: Selce, 12 metres, Croatia, Adriatic, 15 March 2007, Subtidal, rocky. Length: 30 mm. Photographer: Mat Vestjens.
Best regards,
Mat Vestjens
annenmat@natuurlijkmooi.net
Vestjens, M.G., 2007 (Mar 27) Cannibalism? with Janolus cristatus. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19767Dear Mat,
Most nudibranchs have teeth and mouth parts specialised for feeding on their normal food so I don't know if the teeth of a bryozoan feeder would be very good at eating a nudibranch body. Also, looking at the damaged animal, there seems to be a series of small bud-like cerata around the edge of the damaged region which would suggest regrowth is beginning to take place. If so, it would mean the damage was not caused while you were watching. My guess would be that the healthy animal was passing by and was attracted to the other animal by normal chemical communication - and then moved on. I very much doubt it was having a bite of the damaged animal - but I could be wrong.
Best wishes,
Bill Rudman
Related messages
-
Re: Janolus cristatus from Mediterranean
From: Petros Ornithopoulos, March 17, 2009 -
Re: Janolus cristatus from Mediterranean
From: Raphaël Vallotton, August 13, 2007 -
Eggs of Janolus cristatus
From: Richard Lord, July 18, 2007 -
Janolus cristatus from Mediterranean
From: Dominique Horst, June 26, 2007 -
Janolus cristatus from Portugal
From: Carlos Marreiros, July 19, 2006 -
Janolus cristatus from Cyprus
From: Vasilis Athanasopoulos, May 19, 2006 -
Janolus cristatus from Italy
From: Luigi Montevecchi, April 26, 2006 -
Re: Janolus cristatus from Portugal
From: David Abecasis, January 13, 2006 -
Janolus cristatus from Portugal
From: David Abecasis, January 12, 2006 -
Janolus cristatus from Cornwall, UK
From: Judith Oakley, November 3, 2005 -
Janolus cristatus from Fethiye Bay, Turkey
From: Ant Turkmen, July 14, 2004 -
Janolus cristatus from Tunisia
From: Anis, May 2, 2003 -
Janolus cristatus from Scotland
From: Jim Anderson, September 4, 2002 -
Janolus cristatus from Mediterranean
From: Erwin Koehler, September 4, 1999 -
Janolus cristatus from the Netherlands
From: René Lipmann, September 3, 1999