Risbecia pulchella - Stretching ?
June 6, 2008
From: Kamal El Tawil
Concerning message #21047:
Dear Bill,
This beautiful Risbecia pulchella was "standing up fully streched" on a coral tip. I have seen other species do the same and I now wonder if there is a reason for this behaviour. After a few minutes it crawled on the reef.
Locality: Elphinstone Reef, 15 metres, Egypt, Red Sea, 27 May 2008. Length: 60 mm. Photographer: Kamal El Tawil.
Kindest regards,
Kamal
www.coralworld.net
kamal@coralworld.net
El Tawil, K., 2008 (Jun 6) Risbecia pulchella - Stretching ?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/21625Dear Kamal,
In your earlier message I hesitated to give a reason for that other characteristic Risbecia behaviour - trailing. There is a whole field of research, called ethology, which studies animal behaviour. This 'stretching behaviour' is often seen, but like 'trailing', no scientific research has been done on it. However there seems to be a perfectly reasonable explanation for stretching - but remember it is just an hypothesis. Stretching and waving the head and neck around is seen in many snails and slugs both in the sea and on the land. These animals are essentially blind, so they rely on other senses such as touch and smell to discover where they are. When they are crawling along and reach the top of a rock or the edge of a leaf, they can't see the gap in front of them, but they can certainly feel that they are running out of something to crawl on. So I presume the first aim of stretching is to see if their is something solid nearby which they can move to. In water, stretching and waving the head around also waves the rhinophores, or other chemosensory organs on the head, so they can 'look' for interesting smells, which could mean food or a mate. As you illustrate in your photos, after stretching for awhile and finding nowhere to go, or no smells to investigate, they just settle down and blindly crawl away.
Best wishes,
Bill Rudman
Related messages
-
Re: Risbecia pulchella at rest
From: Ron Velarde, February 24, 2009 -
Risbecia pulchella at rest
From: Valda Fraser, February 16, 2009 -
Trailing Risbecia pulchella from the Red sea
From: Kamal El Tawil, April 9, 2008 -
More Risbecia ghardaqana from Thailand?
From: K. Kalani Patterson, February 5, 2008 -
Re: Risbecia ghardaqana from Hurghada, Egypt
From: Yahia Mokhtar, October 30, 2007 -
Risbecia pulchella from the Red Sea
From: Larry Dupriest, October 30, 2007 -
Risbecia ghardaqana ? from Muscat, Oman
From: Yahia Mokhtar, September 21, 2007 -
Mating Risbecia pulchella from Tofo, Mozambique
From: Natasja Vandeperre, August 24, 2007 -
Risbecia ghardaqana? from Indonesia
From: Grace Wong, August 18, 2007 -
Re: Rispecia ghardaqana? from South Africa
From: Colin Ogden, May 9, 2007 -
Risbecia ghardaqana? from the Red Sea
From: Kamal El Tawil, July 24, 2006 -
Risbecia pulchella from the Red Sea
From: Kamal El Tawil, March 6, 2006 -
Periclimenes imperator on mating Risbecia pulchella
From: Matan Ninio, August 3, 2005 -
Risbecia pulchella from Reunion Island
From: Stefaan Dewulf, February 1, 2005 -
Risbecia pulchella from Thailand
From: Spencer Huang, December 8, 2003 -
Risbecia pulchella from Red Sea
From: Leo de Pee, May 22, 2003 -
Risbecia pulchella from the Red Sea
From: Oren Lederman, May 17, 2003 -
Chromodoris hintuanensis or R. pulchella?
From: Asther M. Lau, May 10, 2003 -
Risbecia ghardaqana from Andaman Sea
From: Mary Jane Adams, April 8, 2003 -
Risbecia pulchella from the Red Sea
From: Ilan Ben-Tov , April 8, 2003 -
Risbecia pulchella from the Andaman Sea
From: Mary Jane Adams, April 8, 2003 -
Re: Risbecia ghardaqana trailing
From: Erwin Koehler, April 8, 2003 -
Risbecia ghardaqana trailing
From: Sarah Heaney, March 29, 2003 -
Risbecia ghardaqana - 'trailing' behaviour
From: Larry Dupriest, March 2, 2003 -
Risbecia ghardaqana from sthn Thailand
From: Priscilla Yeo, January 25, 2003 -
Re: Risbecia pulchella vs. ghardaqana
From: Ron Velarde, April 6, 2002 -
Risbecia pulchella or ghardaqana (2)
From: Erwin Koehler, April 5, 2002 -
Risbecia pulchella vs. ghardaqana
From: Erwin Koehler, April 5, 2002 -
Risbecia pulchella from Bali
From: Stuart Hutchison, April 4, 2002 -
Risbecia ghardaqana from the Red Sea
From: Jim Anderson, January 31, 2002 -
Is this Risbecia ghardaqana?
From: Doug Segar, March 14, 2001 -
Risbecia pulchella - range extension
From: Michael D. Miller, March 14, 2001 -
Risbecia pulchella without gills
From: Valda Fraser, January 12, 2001 -
Risbecia pulchella from Oman
From: Gordon T. Smith, October 30, 2000 -
Risbecia from the Seychelles
From: Dick Ballendux, November 12, 1999 -
Risbecia pulchella from Thailand
From: Bill Rudman, April 12, 1999 -
'Trailing' in Risbecia pulchella
From: Bill Rudman, April 11, 1999 -
'Trailing' in Risbecia ghardaqana
From: Erwin Koehler, April 9, 1999