Pieris wing chemicals

[Guy Van de Poel & A. Kalus]

Hi all,
 
I just read an article about an alternate way to relax leps (using leaves,
cut to pieces of Prunus laurocerasus - cherrylaurel), which avoids (on
Pierids) the greenish spots caused by water drops condensing on the wings.
However, I only had these spots on Pieris brassicae and P. rapae, never on
any of the P. napi group (oleracea, virginiensis, bryoniae, ...)
 
Question one:
This would mean that the wings of P. brassicae and P. rapae contain
chemicals that react with the water and those of P. napi group (s.l.) don't.
Does anybody know the reason for this - has there been any research on this?
 
Question two:
In the article, the author says a disinfectant should be added, but not
Thymol as it causes the smaller leps (blues) to get 'oily', however he does
not mention an alternative. I use Phenol, which does not seem to help much,
and I sometimes have 'oily' leps too. Any recommendations?
 
Thanks,
 
Guy.
 
Guy Van de Poel
Guy_VdP at t-online.de
 
Royal Entomological Society of Antwerp
http://www.freeyellow.com/members/fransjanssens/index.html
 
 
 
 
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