On Mon, 18 Jun 2001 22:19:41 +0000 Ross Mayhew wrote:
> I will try again (i really hate being ignored!!): Do worms often burrow
> into living cones (as opposed to simply living on them and leaving a
> calcareus test)?  The worm-trace with critters that burrow into shells
> leave, is usually black and visible through the shell.  Surely lots of
> Conchlers that live in or have visited tropical climes have the answer
> in their storehouses of Shell Lore?

I hesitated to reply before because my answer is based on temperate bivalves!

Oysters (my interest is in _Ostrea edulis_) are afflicted by two "burrowing worms":
(1) _Polydora hoplura_ which seems to penetrate from the edge of the shell or between
growth shoots. There is often an accumulation of mud around the burrow which is etched
into the shell, and the burrow is quite extensive - a hairpin of 1-2cm length, with each
arm being about 2mm. As far as I can tell from the literature, this is the more damaging
of the two species.
(2) _Polydora ciliata_ which seems to etch its burrow almost anywhere on the shell
(although there are usually more near the hinge) and is a small hairpin of approx 5mm
length and 1mm total width. This I have seen also on other temperate shells, as well as in
chalk on the shore - and I would bet on the tropical version of this being your villain!

With Oysters, the major source of damage to the shell comes from burrowing sponges -
_Clione celata_ being the one I am familiar with.


Hope this helps - or at least serves to spark further comment!

Liz

Dr Liz Somerville
Sub-Dean (Academic Affairs)
School of Biological Sciences
University of Sussex
Falmer
Brighton
BN1 9QG

Tel: 01273 877460
internal no: 7460

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