on 12/14/00 8:42 AM, bivalve at [log in to unmask] wrote:

> The Urosalpinx could have been feeding on commensals on the crab carapace.
> The Orlando hypothesis may also have some merit-riding crab back to the next
> oyster patch is quicker than crawling, and probably more fun as well.
>
> Dr. David Campbell

Your comments seem to parallel the abstract I forwarded on the symbiotic
(commensal is more accurate?) relationship between Thais h. floridana and
blue crabs/hermit crabs.

As usual, a little information raises yet more questions. The article deals
with blue crabs and hermit crabs not Limulus as passive transport. And
Thais, Cantharus and Boonea species as mounters, not Urosalpinx. So, both
gastropods who "mount" and their mounting targets are generalized across
taxonomic categories.

Doesn't this suggest that this behavior likely evolved before the divergence
of muricid and buccinid ancestors, etc.?

And whatever stimulates mounting behavior (non-X rated) is not too specific
(olfactory, pattern recognition, and/or motion-detectional) as long as it's
crab-like? After all, there are plenty of acorn barnacles in the sea without
a snail needing to learn to mount a crab in order to find them, right? (I
forgot to mention that my four Urosalpinx riders-of-the-purple-passion
Limulus had nothing in evidence to eat directly where they were perched but
there were some barnacles encrusting the margins of the horseshoe crabs'
carapaces).

From the information in the abstract (snails dismounting quickly in the
presence of oysters), isn't it likely that the need for transport to a new
food source outweighs the need for food on the transporter itself as a
primary reason for the genesis of this behavior?

Groping for some ethological sense,
David Kirsh
Durham, NC