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Subject: Sea shells

Sea shells

From: Helena Jaeschke <helena.jaeschke>
Date: Thursday, November 25, 2004
Jerry Fahey <jfahey [at] siue__edu> writes

>There are small pin holes showing up in quite a few of our sea shell
>collection. Is anyone aware of an insect that feeds off sea shells?
>Or what could be causing this? ...

There are predators which bore holes in living seashells in the sea:
for example, polychaetes attack oysters and abalone. However, the
natural history curator at the Royal Albert Memorial Museum, dave
Bolton,  has not come across insects attacking shells in
collections. He suggests: If the shells were not cleaned of all
organic material, there may be some bacterial or fungal activity
which is attracting insects like collembola, but it's unlikely that
they would be present in sufficient numbers to cause such damage yet
go unnoticed.  Is the periostracum being attacked?  This is an
organic layer, with conchiolin the main component. Otherwise the
shell is mostly calcium carbonate which is not usually part of
insect diets. Molluscs, however, do seek it out for their own
shells. Could it be an aspect of Byne's disease - the chemical
transformations caused by acid vapours? Usually you would see an
efflorescence of salts on the shell surface, but there may be
situations where the periostracum is protecting the outer shell
surface whilst the inner nacreous layers are being attacked.

Hope this helps,

Helena Jaeschke
Conservation Development Officer: Southwest
Royal Albert Memorial Museum
Queen Street
Exeter EX4 3RX
+44 1392 665951

                  Conservation DistList Instance 18:25
                Distributed: Wednesday, December 1, 2004
                       Message Id: cdl-18-25-014
Received on Thursday, 25 November, 2004

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