Double mounting with polyporous fungus blocks

[Richard Worth]

Charley,
I'm relatively new to pinning micros but have quickly become adept by 
necessity, having to pin many small olethrutine tortricids like 
Grapholitha molesta and prunivora.  Including plenty from sticky 
traps!!!  Here's what I've found.  When I started, I noticed that 
some folks in the past had used the inert silicone but I found them 
way too springy.  Just touching the main pin or accidentally 
"plinking" it would cause the micro on the minuten to vibrate 
violently, unless the strip was very, very short.  Then it's usually 
too short for the moth.  I have seen people in the past use little 
chunks of that stuff they call hard composite pinning bottom used in 
museum drawers.  I've had good results with the plastozote.  It tends 
to keep gripping if you remove and replace specimens because the 
holes seem to reclose.  If you get it from bioquip, make sure that 
the blocks are square or at least to spec'd dimensions.  I got one 
order and the strips were very thin and way too flimsy.  They quickly 
replaced them with no hassles.  They are also a cheap way to go. 
Leave finding rare fungi to the mushroom people and work on those 
leps!!(joke).

Cheers,  Rich


>A number of sources advocate double mounting micro moths with polyporous
>fungus blocks (eg. Covell, Eastern Moths, p 21). More recently, Landry &
>Landry, J. Lep Soc. 48:222 state, "Traditionally, blocks have been cut from
>strips of polypore fungi (especially from birch bracket fungus). Normally
>it is easy to procure polypore strips from naturalist supply houses, but
>periodically they tend to become very difficult to obtain."
>
>I recently tried cutting strips from freshly collected specimens of Fomes
>fomentarius [Tinder Conk] from birch and from Phellinus tremulae (Fomes
>igniarius) [False Tinder Conk] from trembling aspen but found both to be
>too hard. Perhaps these are the wrong species or I should have collected
>them at another time of the year. Ideas anyone?
>
>Landry & Landry (p. 223) recommend against using blocks made from balsa,
>cork, and polystyrene foam (styrofoam) as they are either too hard or are
>not rubbery enough to firmly hold a minuten pin. They further state that
>the durability of blocks made from a silicon rubber compound is uncertain.
>Schauff, Collecting and Preserving Insects and Mites (p. 32), however,
>appears to feel that silicone rubber blocks are OK.
>
>I notice that the latest Bioquip catalog (p. 33) lists only inert silicon
>rubber and plastazote double mount strips. Is there still a source of
>supply for polyporous fungus blocks?
>
>It would appear from the above that polyporous blocks are the traditional
>favorite but that plastazote blocks may be the current favorite. Your views
>would be appreciated.
>
>Charley

Richard A. Worth
Oregon Department of Agriculture
Plant Division
rworth at oda.state.or.us
(503) 986-6461