degreasing/green coloration

Richard Worth rworth at
Mon Jan 14 14:26:48 EST 2002

Thanks muchly to all who replied.  I decided to post a summary here. 
It seems that it is certainly brought about by exposure to moisture, 
and is not specific to dead bugs.  Apparently, fumigants have no real 
effect in the relaxer...I, too, use PDB.  Seems to be removable 
sometimes.  It sounds like the color is urea.  Is this a by-product 
of legume and crucifer feeders?... nitrogenous plant compounds or 
from metabolism?  Soluble in some nitrogen based solvent?  Maybe 
ammonia could turn the whole thing green!  Any responses by folks 
that use ammonium carbonate as a dispatcher?  I'll have to try 
different things.

Thanks again,  Rich

>I, too, have only seen this when relaxing.  From what I can tell, 
>water droplets falling directly on the specimens cause it (don't 
>know what the reaction is).  The easiest way to avoid this is, 
>clearly, don't let water droplets get on them, though this is not as 
>simple as it sounds when using a relaxer.  Degreasing also does seem 
>to get rid of these spots *some of the time*.

>It is probably due to high humidity at packing, which then condenses
>into a small water droplet when stored, usually in a cooler location.
>Spots can also appear when relaxing if the humidity level is too high,
>because of temperature drop in the evening.

>My guess would be urea, as it is the pigment coloration present in
>Pierids....  It is often seen on the wings of recently eclosed adults
>before they dry out.
>M.B. Prondzinski

>The most serious case of the phenomenon described by Richard Worth that I
>have seen occurred on a very large Pierid I caught in Rishikesh, Uttar
>Pradesh, India in 2000.  I relax with only water, so Stan's suggestion
>wouldn't apply.  The bug was big and white - with black stripes and a slight
>bluish tint.  I thought I had spilled ink on the wings at first - the
>blue-green staining ran like water colors.  There was significant
>condensation in the relaxer, and it was little drops of water that were the
>culprits.  I hadn't seen this before - at least not to this extent.  It was
>almost as if the bug was painted, and I was ruining the masterpiece with
>exposure to water.
>I have no idea what chemical is responsible, but the secret is clearly
>keeping the specimen away from condensation.
>Mark Walker.

>On one of my first attempts at relaxing I got things too wet by putting the
>things over very hot water.  Got a bluish green color some.  It looked like
>the wing got so moist from condensation that soluble pigments dissolved in
>the moisture and migrated (like paper chromatography) across them wing.  It
>was much like ink separates into components on a wet piece of paper.  These
>were done over pure water (well city water anyway) without added chemicals.
>Barb Beck

>One might try water without ammonia, chloramines, or chlorine.  What comes
>out of the tap is pretty chemical laden -  unusable as is for fish.  Treat
>your tap water with something like AmQuel first and see what happens on a
>disposable specimen.

>I have seen these spots on worn and tattered (even a few fresh)
>  pierids in the field in the tropics many times - presumably caused by
>rain droplets or condensation; so I doubt that using
>pure water without any chemicals in the relaxer would solve the problem.
>Andy Warren

>While this is certainly possible, I tend to agree with Barb - my specimen
>looked as if the coloration was bleeding right from the wing pigment itself
>- not with a reaction from the minerals and stuff in the water.

>This is just a thought.  If this is something that occurs uniquely to
>certain groups, Pierids, it indicates a chemical difference from other
>butterfly groups.  Maybe the chemical(s) that this group possess (that
>other butterfly groups don't have) react with the fungicide in the
>relaxer, resulting in a compound that gives the blue-green color. Change
>the fungicide?  I use PDB, but have not relaxed enough pierids to notice
>whether I get a blue-green color.

>I've had this happen particularly with female specimens; I always assumed
>that I might have pinched a part of the abdomen by mistake, or else
>over-pinched the thorax. The "leak" from the genital end of the abdomen
>doesn't seem to become manifest until the wings have been opened up during
>Yes, it may very well be water droplets getting on the specimen, but I have
>this happen even with specimen being relaxed inside the glassine envelope.
>So it may also be possible when water vapor comes into contact with the
>specimen. But it still seems to happen to me when I overpinch (or maybe it
>is worse when I overpinch).

>I asked the same question some time ago, no answers.
>It looks to me like P. rapae and brassicae are much more susceptible to this
>than the species from the napi group (venosa, oleracea, virginiensis,
>melete, bryoniae, ...).
>I also noticed it on Gonepteryx species, especially the females.
>If there is a cure to this, I would surely like to hear about it.

>Has any body every done any formal research into this?  Like do various
>gasses  alter wing coloration type of thing.

>I will try (clothes) dryer water, as that should not contain any ions
>(chemicals) (or de-ionised water).
>However I do not expect that to be any better, as also others found that it
>was the condensation dripping on the specimens causing the greenish
>coloring - condensation which should not contain the chemicals in the water
>straight from the tap.  But nobody seems to be aware of a cure ?

>----- Original Message -----
>From: Richard Worth <rworth at>
>To: <jadams at>; <leps-l at>
>Sent: vrijdag 11 januari 2002 19:15
>Subject: Re: degreasing
>  > Hey group,
>  > Speaking of green coloration, does anyone know what that blue-green
>  > staining is that you sometimes get on Pierids when you try to relax
>  > them?  I've seen it in both those that were relaxed in glassine
>  > envelopes and those not.  I originally thought it was something in
>  > the envelopes but maybe not.  I never see it until relaxing begins.
>  > Is there a remedy?
>  > Cheers,  Rich

Richard A. Worth
Oregon Department of Agriculture
Plant Division
rworth at
(503) 986-6461
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 6577 bytes
Desc: not available
Url : 

More information about the Leps-l mailing list