What is Philinopsis cyanea doing?
August 6, 2008
From: Valda Fraser
Dear Bill
I found a pool on a wide beach that had been caused by high seas. Unfortunately the pool was in the process of drying out. On the edges of the water, Philinopsis cyanea (maybe a dozen of them) were creating these sacs - perhaps to lay eggs in before they died. What do you think?
Locality: Pomene, 20 cm, Mozambique, Indian, 15 February 2008, Pool on beach. Length: 70 mm. Photographer: Valda Fraser.
Best wishes
Valda
valdafraser@mweb.co.za
Fraser, V.J., 2008 (Aug 6) What is Philinopsis cyanea doing?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21769
Dear Valda,
If you look at the close-ups I have included, you will see that the sacs are in fact filled with strings of small white eggs. Aglajids have this strange way of putting their eggs in the egg sac by wrapping the egg string around their head and then gradually 'pushing' the string and the egg sac enclosing it off the front of the head. Your photo illustrates the process rather well.
I am not quite sure of your description of the pool the aglajids are in. Do you mean it is above the usual high tide level and so when it dries out that is the end for Philinopsis, or is it likely to fill up again at the next high tide? In either case, it is interesting how many sea slugs start egg laying when they are in dire straits. Often when you collect them they will lay eggs in dishes, bottles etc, almost as though they know their end is near and this is their last chance to pass on their genes. Interestingly often the 'egg string' contains no eggs, sometimes just a ribbon of yolk, and sometimes the eggs are unfertilised. These 'mistakes' would suggest to me that going through the motions of egg-laying is an innate response to stress. Certainly it is not a bad response, because if the animals do have fertilised eggs it is better to have them out than in, and if the animal is about to die it really doesn't matter about the 'mistakes'.
Best wishes,
Bill Rudman
Related messages
-
Dark colour form of Philinopsis cyanea
From: Hugues Flodrops, August 5, 2008 -
Philinopsis cyanea from Reunion Island
From: Hugues Flodrops, February 18, 2008 -
Philinopsis taronga? from Reunion Island
From: Hugues Flodrops, February 18, 2008 -
Philinopsis cyanea from Perth
From: Brent Murdoch, January 17, 2007 -
Philinopsis cyanea? from Taiwan
From: Ching-Yao Chan, May 17, 2006 -
Philinopsis cyanea? from Victoria, Australia
From: Trevor McMurrich, March 24, 2006 -
Re: Aggregation of Stylocheilus striatus in Indonesia [1]
From: Paul Whitehead, January 23, 2006 -
Philinopsis gardineri? from Reunion Island
From: Philibert Bidgrain, December 13, 2005 -
Re: Philinopsis cyanea mating in Reunion Island
From: Francis & Pirjo Pellet, November 25, 2005 -
Philinopsis cyanea spawning at Reunion Island
From: Philibert Bidgrain, November 25, 2005 -
Two big Philinopsis cyanea mating in Reunion Island
From: Philibert Bidgrain, November 23, 2005 -
More colour forms of Philinopsis cyanea
From: Dong Bum Koh, June 13, 2005 -
Philinopsis cyanea ... eating?
From: Binyamin Koretz, April 28, 2005 -
Philinopsis cyanea from South Korea
From: Dong Bum Koh, April 14, 2005 -
Philinopsis depicta? from the Red Sea
From: Binyamin Koretz, April 14, 2005 -
Philinopsis cyanea? from Indonesia
From: Francis & Pirjo Pellet, January 13, 2004 -
Philinopsis cyanea from Port Stephens
From: Leanne&David Atkinson, May 13, 2003 -
Philinopsis cyanea & possible egg mass
From: Leanne Atkinson, May 9, 2003 -
Philinopsis cyanea from Lembeh Strait
From: Mary Jane Adams , February 6, 2003 -
Philinopsis cyanea from Lizard Is
From: Nils Anthes, February 3, 2003 -
Philinopsis cyanea from Lord Howe Island
From: W.B. Rudman, January 10, 2003 -
Philinopsis cyanea from Lord Howe Is.
From: Ian Hutton, December 6, 2002 -
Philinopsis mating from Korea
From: Dong Bum, Koh, June 17, 2002 -
Philinopsis cyanea from Sulawesi
From: Mary Jane Adams, May 4, 2002 -
Philinopsis cyanea mating
From: Julie Marshall, May 4, 2001 -
Philinopsis cyanea from New South Wales
From: Erik Schloegl, April 3, 2001 -
Philinopsis from Mauritius
From: Owen Griffiths, July 27, 1998