Chromodoris willani & C. magnifica feeding

February 23, 2009
From: Patricia Dilworth

Hi Bill,

I suspect you have photos of Chromodoris willani and C. magnifica eating, but we are always on the lookout for these "action" pictures for you!

Locality: Raja Ampat , 50 ft., Indonesia, Banda Sea, 15 November 2008, reef. Photographer: Patty Dilworth.

Thanks,
Patty Dilworth

padilworth@aol.com

Patty Dilworth, 2009 (Feb 23) Chromodoris willani & C. magnifica feeding. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22273

Dear Patty,

Action photos are always welcome and it does not matter if we already have photos of the same animal feeding. In fact it is best we have multiple observations because then we can be more confident that the food item is a normal part of the diet rather than a strange one-off activity.

Concerning the species. The upper one is certainly C. willani, but the lower one is Chromdoris annae. There are a number of similarly coloured species but one sure way to identify C. annae are the small dark specks all over the bluish parts of the mantle, which can be seen in the close-up alongside. Also in the close-up we can see a large cavity in the sponge just above the slug, which certainly looks like feeding damage.

This dark grey sponge is almost certainly a species of Petrosaspongia, which both species have been reported on before [see messages #12039; #12040; #12005; #16257]. Your photo then is valuable confirmation of the food choice of these two species. Finding two similarly coloured species together on the same food sponge is also interesting because it suggests why there are these groups of similarly coloured species. I have described a group of red-spotted species on a separate page and explain how I think that these groups of similarly coloured species living in close geographic proximity have evolved to warn predators to leave that colour pattern alone. I suspect that these more widely spread black-lined species also 'teach' predators to leave their colour pattern alone by grouping together on the same food sponges. In this way all the black-lined species would share the load of 'teaching' predators that black-lined slugs contain extremly distasteful chemicals and aren't worth biting.

Best wishes,
Bill Rudman

Rudman, W.B., 2009 (Feb 23). Comment on Chromodoris willani & C. magnifica feeding by Patricia Dilworth. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/22273

Related messages

  1. Chromodoris willani feeding, (red) sponge - Philippines
    From: Marcel Tanke, January 21, 2009
  2. Chromodoris willani feeding, white sponge - Philippines
    From: Marcel Tanke, January 21, 2009
  3. Re: Chromodoris willani from Yap, Micronesia
    From: Mitsue Yasui, September 19, 2008
  4. Chromodoris willani from Yap, Micronesia
    From: Mitsue Yasui, September 9, 2008
  5. Strange mutation from the Philippines
    From: Jeffrey de Guzman, March 19, 2008
  6. Re: Chromodoris willani - eggs & food
    From: Barbara Hanchard, December 12, 2007
  7. Chromodoris willani - eggs & food
    From: N. Barbara Hanchard, December 11, 2007
  8. Chromodoris willani from sthn Queensland
    From: Gary Cobb, August 8, 2007
  9. Chromodoris willani laying eggs in the Philippines
    From: Mike Krampf, August 7, 2007
  10. Another Chromodoris willani?
    From: Ken Tucker, August 7, 2007
  11. Chromodoris willani on the prowl
    From: Ken Tucker, August 7, 2007
  12. mutant Chromodoris willani
    From: Carlos Munda, July 19, 2007
  13. Chromodoris willani feeding in Sulawesi?
    From: Mike Krampf, November 29, 2006
  14. Chromodoris willani - feeding (3)
    From: Guido & Philippe Poppe, April 8, 2006
  15. Chromodoris willani - feeding (2)
    From: Guido & Philippe Poppe, April 8, 2006
  16. Chromodoris willani - feeding (1)
    From: Guido & Philippe Poppe, April 8, 2006
  17. Chromodoris willani from Sabah, Malysia
    From: Asther Lau, March 2, 2006
  18. Chromodoris willani from Sabah
    From: Asther M. Lau, January 18, 2006
  19. Chromodoris willani feeding?
    From: Asther Lau, December 6, 2005
  20. Re: Chromodoris willani feeding
    From: Roberto Sozzani, January 28, 2004
  21. Re: Chromodoris willani feeding
    From: Roberto Sozzani, January 26, 2004
  22. Chromodoris willani feeding
    From: Roberto Sozzani, January 23, 2004
  23. Chromodoris willani - where it lives
    From: Andrew Watts, July 31, 2003
  24. Chromodoris willani from Sulawesi
    From: Asther M. Lau, May 16, 2003
  25. Chromodoris willani from nthn Sulawesi
    From: Helmut Schirmböck , July 11, 2002
  26. Re: Chromodoris willani laying eggs
    From: Nick Gill, November 22, 2001
  27. Chromodoris willani laying eggs
    From: Nick Gill, November 12, 2001
  28. Chromodoris willani from the Philippines
    From: Mary Jane Adams , June 5, 2001
  29. Re: Chromodoris willani for sale in Brazil
    From: Paulo Rubens Cabral, August 19, 2000
  30. Chromodoris willani for sale in Brazil
    From: Carlo Magenta-da-Cunha, April 28, 2000
  31. Chromodoris willani from SE Sulawesi
    From: Lindsay Warren, November 29, 1998

Show factsheet and all related messages