Pea crabs symbiotic with polychaetes
buzbay at cape.com
Fri Nov 30 16:32:41 EST 2001
I have worked with the "pea crabs" since 1957 when I begain my grad
career at the Friday Harbor Labs, U. of Wash. I worked most with the
bivalve parasite spp but collected numerous forms that are symbiotic with
polychaetes, and some other vermiform taxa. I had postdocs in Denmark
and Scotland and was able to collect in most European waters. Several
things are important: the likes of Fabia (really should be Pinnotheres)
and Pinnotheres should be in a separate family relative to the pinnixids,
which have completely different life histories. I spoke several times with
Waldo Schmidtt about this issue before he died.
The several species of Pinnotheres (and Fabia and others) have two
distinct crab instars which are free-living, usually in the water column
(this is described in my paper in Pacific Science). The pinnixids don't
carry-on this way and the males and females live together in bivalve (and
I suspect polychaete) hosts. In Pinnotheres, the males and females
copulate in the open water, with the female (fully inseminated) returning
to the host spp to complete the series of instars leading to the so-called
Stage V ovigerous form. All this in spite of whart Christensen and
McDermott said earlier about the males seeking out females in the host
bivalves of the latter!
Pinnixa faba and littoralis always interested me in as much as that they
seemed to violate Gause's hypothesis about two spp NOT occupying the
same niche'. I suspect that P. eburna, schmitti, and others are equally
interesting in how they share their several vermiform hosts.
I would be glad to correspond with you in these regards; Mary Petersen,
the Copenhagen Museum might also be a font of knowledge as she
worked widely with worms in the U.S. southeast and is a great observer!
Best of luck and keep in touch. I have worked with several species with
re: to DNA (with colleagues at MBL) to see if any cryptic spp are involved
where one sp, P. maculatus, occupies two or more host spp.
Cheers, Jack Pearce, North American Editor, Marine Pollution Bulletin
Buzzards Bay Lab., 54 Upland Av., Falmouth MA 02540 USA
buzbay at cape.com, 508-540-4572, fax 508-457-0105
Greg Farley wrote:
> [apologies for crossposts!]
> Dear colleagues:
> Hello! By way of introduction, I am a graduate student at Florida State
> University in Tallahassee. My research revolves around the evolution and
> ecology of commensalism, and I'm using pea crabs (Brachyura:
> Pinnotheridae) as a model system.
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