Titanium snails

Instead of having shells of metallic titanium, you might want to look
into
ceramics and cermets. Take a look at the hardness of various Ti-bearing
compounds like titanium boride (TiB2), titanium nitride (TiN) or
titanium
carbide (TiC), for example... They make cutting tools out of this stuff
to
mill steel with, so you can imagine how hard it is.

Ceramics have a number of weaknesses, too, like being fairly weak
against
physical or thermal shock.

Personally, I would find these more likely than metallic Ti. And your
wasps
could have a substance that works on the Ti content regardless (I have
no
idea how reactive Ti itself is, however... Could collapse the whole
argument!).

FWIW.

-- 
Edward Lipsett
Intercom, Ltd.
Fukuoka, Japan
Tel: 092-712-9120
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