June 24, 2006
From: R. Grooters & M. Snoek
Here are two pictures of Platydoris cruenta which we think, are laying egg ribbons after mating. Since there isn't much on this species on the forum, we thought it might be of interest.
Locality: Anilao, Batangas, 7 metres, Philippines, West Pacific, 17 November 2005, Sand and coral patches. Length: 10 cm. Photographer: Reindert Grooters.
Reindert Grooters and Mieke Snoek
R. Grooters, R. & Snoek, M., 2006 (Jun 24) Platydoris cruenta - egg laying and mating?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/16886
Dear Reindert & Mieke,
Thanks for these interesting photos. The Platydoris are not mating and egg-laying as you thought, but the orange bits you thought were eggs are in fact a sponge that the two slugs are eating. If you look at the close-ups you can see where the sponge has been damaged by their activities. This is a very interesting record as I am pretty sure that there is no information in the scientific literature on the type of sponge this species eats. I can't tell you what the sponge is off-hand but I think there is enough in your photo for a sponge expert to give at least a tentative identification.
By coincidence I am just posting a message on a feeding cluster of Hypselodoris fontandraui [message #16948]. In that message I mention that when you see a group of nudibranchs together your first thought should be that they are feeding - the close proximity may lead to mating, but it's usually the food that brings them together.
Re: Platydoris cruenta from the Philippines
From: Marcel Tanke, July 22, 2008
Re: Platydoris striata or P. cruenta from Reunion Is.
From: Philibert Bidgrain, April 25, 2008
Platydoris cruenta with red and orange patches
From: Julie Marshall, June 24, 2002
Platydoris cruenta from the Philippines
From: Erwin Koehler, March 3, 2001