January 23, 2006
From: Paul Whitehead
Concerning message #15378 on aggregation of Stylocheilus:
As promised attached are some photos of the other two aggregation species, which all aggregated with the same week and on the same site (Retal Larry, Lembeh Straits) following the September full moon.
Locality: Retak larry. Lembeh Straits, Indonesia. Depth: 3 meters. 15 September 2005. black sand beach with sparse cover. Photographer: Paul Whitehead
Immediately after the Stylocheilus aggregation the "white" species [see message #15630 ] aggregated over the site covering an area of about 20 meters by 20 meters and avaeraging about 10 animals per square meter. Whilst this aggregation was occurring, this third species aggregated covering the same area with about 10 animals per square meter again.
The whole cycle of the three aggregations lasted 1 week.
email@example.comWhitehead, Paul, 2006 (Jan 23) Re: Aggregation of Stylocheilus striatus in Indonesia . [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/15629
This is Philinopsis cyanea, another species with a reputation for irregularly occurring in large aggregations. I recall seeing two such aggregations, one in Zanzibar in 1971, and another in mainland Tanzania a few years later - but they don't seem to be a regular occurrence - or perhaps there are too few people looking out for them. Aggregations like this are a good opportunity to see the range of colour variation in a species. I see that in your photo alongside there is a small specimen of the 'white swarmer' Gymnodoris ceylonica.
Philinopsis cyanea is another eater of opisthobranchs, usually cephalaspidean bubble shells, but it also feeds on Stylocheilus [see Mike Roberts message #14082]. As with Gymnodoris, I suspect the timing of the Philinopsis aggregation with the Stylocheilus aggregation is a coincidence rather than a consequence. That is not to say that the Philinopsis would not have taken advantage of so much food around.
What is Philinopsis cyanea doing?
From: Valda Fraser, August 6, 2008
Dark colour form of Philinopsis cyanea
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Philinopsis cyanea from Reunion Island
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Philinopsis cyanea from Perth
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Philinopsis cyanea? from Taiwan
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Philinopsis cyanea? from Victoria, Australia
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Philinopsis gardineri? from Reunion Island
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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
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Philinopsis cyanea ... eating?
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Philinopsis cyanea from South Korea
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Philinopsis depicta? from the Red Sea
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Philinopsis cyanea? from Indonesia
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Philinopsis cyanea from Port Stephens
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Philinopsis cyanea & possible egg mass
From: Leanne Atkinson, May 9, 2003
Philinopsis cyanea from Lembeh Strait
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Philinopsis cyanea from Lizard Is
From: Nils Anthes, February 3, 2003
Philinopsis cyanea from Lord Howe Island
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Philinopsis cyanea from Lord Howe Is.
From: Ian Hutton, December 6, 2002
Philinopsis mating from Korea
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Philinopsis cyanea from Sulawesi
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Philinopsis cyanea mating
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Philinopsis cyanea from New South Wales
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Philinopsis from Mauritius
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