June 23, 2000
From: Jeff Goddard
Here is a photo I took in the lab in 1984 of a 10 mm long Flabellina trilineata and its amphipod crustacean mimic, Podocerus cristatus (Thompson, 1879), from Cape Arago, Oregon, USA. I have also enclosed a brief account of the biology and range of the aeolid.
Flabellina trilineata is a seasonally abundant aeolid ranging from Baja California, Mexico to Alaska (Behrens, 1991). It feeds on hydroid polyps, especially those of Tubularia spp. and Eudendrium californicum (McDonald & Nybakken, 1978; Goddard, 1984). Flabellina trilineata always have white pigment on their rhinophores and cephalic tentacles, but one color form has distally on these appendages an additional, overlying red orange pigment. Both color forms consistently have three white stripes running the length of the body.
The color form of the amphipod mimic shown here has only been collected from the southern Oregon coast, often under the same overhangs and cobbles as its aeolid model (Goddard, 1984b, unpublished observations). Most amphipods are edible to fish, and this mimicry is likely an example of Batesian mimicry, in which an edible organism gains protection from its predators by mimicking an inedible or repugnant organism.
A purple and orange colored form of Podocerus cristatus occurs in central California (Gosliner & Behrens, 1990), where the stunningly purple and orange colored aeolid, Flabellina iodinea (Cooper, 1862) is often one of the most abundant and conspicuous nudibranchs.
• Behrens, D.W. 1991. Pacific coast nudibranchs. Sea Challengers: Monterey, California.
• Goddard, J.H.R. 1984. The opisthobranchs of Cape Arago, Oregon, with notes on their biology and a summary of benthic opisthobranchs known from Oregon. The Veliger, 27(2): 143-163.
• Goddard, J. 1984b. Presumptive Batesian mimicry of an aeolid nudibranch by an amphipod crustacean. Shells and Sea Life [previously and subsequently the Opisthobranch Newsletter] 16: 220-222.
• Gosliner, T. M. & D. W. Behrens. 1990. Special resemblance, aposematic coloration and mimicry in opisthobranch gastropods. Pp. 127-138 in, M. Wicksten (ed.), Adaptive coloration in invertebrates. Texas A&M University Sea Grant Program: College Station, Texas, USA.
• McDonald, G.R. & J.W. Nybakken. 1978. Additional notes on the food of some California nudibranchs with a summary of known food habits of California species. The Veliger, 21(1): 110-119.
firstname.lastname@example.orgGoddard, J.H.R., 2000 (Jun 23) Flabellina trilineata and its amphipod crustacean mimic. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/2608
Thanks for the photos. It's quite a coincidence to have both your message and Bruce Wight's at the same time. It certainly is an amazingly coloured amphipod.
I would be interested in your comments on Bruce Wight's photo of animals without white lines. Unless there is an amazing Flabellina mimic it looks like this species does not always have white lines.
Growth on Flabellina trilineata from California
From: John Yasaki, May 8, 2009
Re: Flabellina trilineata from California
From: Clinton Bauder, August 5, 2006
Flabellina trilineata from California
From: Aidan Hampson, July 6, 2006
Flabellina trilineata feeding
From: James Lyle, August 1, 2005
Flabellina trilineata? from California
From: Denise Weisman, June 3, 2005
Flabellina trilineata juveniles
From: Sean Kearney, March 23, 2004
Flabellina trilineata laying eggs
From: Bruce Wight , August 4, 2003
Flabellina trilineata from British Columbia
From: Clinton Bauder, January 21, 2003
Flabellina trilineata from San Miguel, Calif.
From: Bruce Wight, August 12, 2002
Flabellina trilineata from Canada
From: Marli Wakeling, December 19, 2000
Re: Flabellina trilineata rhinophores
From: Bruce Wight, June 30, 2000
Re: Flabellina trilineata
From: Bruce Wight, June 27, 2000
More observations on Flabellina trilineata
From: Jeff Goddard, June 26, 2000
Observations on Flabellina trilineata
From: Bruce Wight, June 23, 2000