Rotating heads

[Todd Redhead]

Hi Mark,

I, too freeze most everything I catch.  (The stuff I can't mount immediatly 
anyway.)  Although many specimens do end up with a turned head - I have not 
really had a problem with them staying that way.  What I do is this: let the 
insect thaw out for about 20 mins.  Then while the wings are still folded up 
I check the position of the head. If the head needs to be rotated I use my 
tongs to turn it the other way.  (If the lep is large enough, I will 
sometimes just use my fingers to do this.)  The trick, though, is to 
overrotate it - not just turn it to the position it will finally be in.  I 
hold the head in that overrotated position for 20 or 30 seconds so that when 
I let it go it stays turned in that direction.  I then flex the wings, 
insert the mounting pin, etc. and do the final spread.  During this time I 
find the head will often 'creep' back into the position that it was frozen 
in but not nearly as far.  If everything works out right - the head will 
often end up in the straight on position.  If not - a couple of '000' pins 
is all it takes to hold it and the antenna in position.  I do my dried leps 
the same way after they have been in the relaxer for 24 hrs although the 
process of overrotating the heads sometimes leaves me in a bit of a sweat.  
(The amount of sweat depends on how much $ I spent on that insect.)  The 
heads are usually stiffer on dried insects as compared to the stuff taken 
out of the freezer.

Todd


From: Kenelm Philip <fnkwp at aurora.alaska.edu>
Reply-To: fnkwp at aurora.alaska.edu
To: <leps-l at lists.yale.edu>
Subject: Rotating heads
Date: Sun, 15 Apr 2001 16:13:50 -0800 (AKDT)


Mark Walker asked about rotating heads of papered butterflies when spread-
ing them. I have noticed the same problem--with papered material the head
often ends up rotated to one side or the other, making it difficult to
position the antennae correctly.

What I do is as follows: 1) make sure the specimen is fully relaxed--
which takes about 24 hours in my relaxer. 2) after pinning the specimen
through the thorax, and before pinning it into the groove in the spreading
board, inspect the head position. If the head is rotated, use a probe to
rotate it about the same amount in the opposite direction. One or more such
attempts will usually bring the head, after you remove the probe, to
something close to the correct position as far as rotation goes. 3) pin
the specimen to the board and spread.

I have never had a head 'lock' into the rotated position--the head always
rotates freely when pushed. However, I don't freeze them--I use ethyl
acetate to kill them. Maybe something about freezing does that?

							Ken Philip
fnkwp at uaf.edu





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