September 4, 1998
From: Bob Bolland
Here is a scan of a delightful aeolid (Favorinus?) from Okinawa. This is the first time I've seen this beautiful animal. It was collected by US Navy Cmdr. Keven Reed on 7 June, 1998 from Horseshoe Cliffs in 21 plus meters. The animal was found on a Hexabranchus egg ribbon. According to Keven, at the time the animal was collected, the rhinophores were the same color as the cerata. The animal was then placed in a home aquarium until it was given to me twelve days later, whereupon I took the accompanying photograph. The rhinophores changed from red to black from the time it was collected until the time it was photographed (TL: 22mm). I'm not sure whether the color change was rapid or done in slow increments.
Was the color change due to stress from within the aquarium, or do other factors play a roll in this?
OKINAWA, 21 August 1998
firstname.lastname@example.orgBolland, R.F., 1998 (Sep 4) Favorinus from Okinawa. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/224
It certainly looks like a Favorinus and being on another opisthobranch's eggs is a pretty good sign its a Favorinus, for as you know opisthobranch egg eating is a characteristic of the genus. Its black ridged rhinophores certainly look a bit like those of Favorinus tsuruganus Baba & Abe, 1964, but that species is essentially yellow with black-tipped cerata.
Concerning colour changes. Some species such as Favorinus japonicus change colour depending on the colour of the eggs they are feeding on. But the colour change is due to the colour change of the gut contents not the skin pigment. As the rhinophore colour is probably skin pigmentation I'm not sure why it changed to black.
Favorinus cf. mirabilis from Reunion Is.
From: Sully Bachel, February 3, 2009
Favorinus cf. mirabilis eating Hexabranchus eggs
From: Ugo Gaggeri, December 6, 2006
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Favorinus cf. mirabilis from Mauritius
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Re: Favorinus cf. mirabilis
From: Jim Anderson, July 31, 2002
Favorinus eating Hexabranchus eggs
From: Jim Anderson, July 28, 2002
Favorinus sp. 2? from Madagascar
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