Roboastra gracilis mating ritual

April 16, 2005
From: Karen Willshaw


Hi Bill,
Greetings from the sandbar in the middle of the Indian Ocean - aka Cocos (Keeling) Islands. These two Roboastra gracilis were caught in the act. I do apologise for the clarity of the images, it was the best I could do at the time.

Locality: Cocos (Keeling) Islands, Australian Indian Ocean Territories. Indian Ocean. Depth: 14 metres. Length: 4 mm. 10 April 2005. rocky substrate & sand. Photographer: Karen Willshaw.

Karen Willshaw

karen@IkanImages.com

Willshaw, K., 2005 (Apr 16) Roboastra gracilis mating ritual. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13503

Thanks Karen,
I have often wondered if this species, which feeds on other nudibranchs,  is partial to cannibalism. If so, it would make mating a dangerous pastime - as some spiders discover. I have included a close-up of the skin of one of your animals as it shows the nature of the yellow spots and lines on this species very well. You can clearly see a thin line across the yellow. This is a crack or opening to a deep fold or groove in each of these yellow regions, and the skin is highly glandular exuding a yellowish viscous secretion when the animal is disturbed. Species of Tambja and Nembrotha have similar glandular pits or grooves disguised as coloured lines.
Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Apr 16). Comment on Roboastra gracilis mating ritual by Karen Willshaw. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13503

Factsheet

Roboastra gracilis

Related messages

  1. Roboastra gracilis from Mozambique
    From: Valda Fraser, August 7, 2008
  2. Re: Roboastra gracilis from Thailand.
    From: K. Kalani Patterson, February 7, 2008
  3. Roboastra gracilis from Indonesia
    From: Edward F Dixon, September 21, 2007
  4. Roboastra gracilis from East Malaysia
    From: Mike Krampf, July 16, 2007
  5. Re: Roboastra gracilis from Thailand.
    From: Vie Panyarachun, June 27, 2007
  6. Roboastra gracilis from Thailand.
    From: Vie Panyarachun, June 26, 2007
  7. Roboastra gracilis from Heron Island
    From: Simon D. Power, May 16, 2006
  8. Roboastra gracilis on Scorpion Fish
    From: Aaron Smith, February 25, 2006
  9. Re: Roboastra gracilis eating Nembrotha kubaryana
    From: Rie Nakano, February 14, 2006
  10. Roboastra gracilis eating Nembrotha kubaryana
    From: Ross Gudgeon, February 13, 2006
  11. Roboastra gracilis from Mozambique
    From: Riaan Marx, March 3, 2005
  12. Roboastra gracilis from Malaysia [2]
    From: Asther M. Lau, September 12, 2003
  13. Roboastra gracilis from Malaysia
    From: Asther M. Lau, September 11, 2003
  14. Roboastra gracilis from Saudi Arabia
    From: John Chuk, July 18, 2002
  15. Roboastra gracilis from Malaysia
    From: Richard Houghton, July 16, 2002
  16. Roboastra gracilis from west Malaysia
    From: Kheong Sann Chan, July 12, 2002
  17. Roboastra gracilis from Fiji
    From: Daniel Geiger, October 23, 2001
  18. Roboastra gracilis from Australia
    From: Marli Wakeling, October 9, 2001
  19. Roboastra gracilis from Fiji
    From: Ken Tucker, July 22, 2001
  20. Roboastra gracilis from the Solomon Islands
    From: Mary Jane Adams, February 1, 2001
  21. A spotted Roboastra gracilis
    From: Mary Jane Adams, August 8, 2000
  22. Roboastra gracilis from SE Sulawesi
    From: Lindsay Warren, July 18, 2000
  23. Spotted Roboastra gracilis from North Queensland
    From: Paul Osmond, March 2, 2000

Show factsheet and all related messages