Voucher specimens

[Bart Vanholder]

At 12:10 20/09/97 GMT, Neil Jones wrote:

>The case in point is a recent one and concerns a rare British Moth the Fiery
>Clearwing (Bembecia chrysidiformis). The species is being considered for
legal
>protection in the UK. A site was badly damaged by collecting when the larvae
>were removed with the host plant.

For this species (the current name is Pyropteron chrysidiforme) I would
like to add a short note. This clearwing species is one feeding inside the
plant-roots.
Usually chrysidiforme attacks (not uncommonly the same plants) for
consecutive years until eventually the plant dies (suffering the predation
after many years). This can go very fast in heavy populations...there are
several cases known in which a population of a few hundred plants were
terminated to only 7 plants after 2 years (and the cause was P.
chrysidiforme..)
At that time the species has to search for a new bunch of hostplant.  This
migth be also what was going on...if all plants in the neighbourhood were
attacked the species has little change to survive if no new biotopes can be
reached. If the biotope is thus not very abundant (anymore) in foodplant
the (local) population can die out. For this purpose the use of P.
chrysidiformis was even suggested as a biological control for Rumex-pest in
Australia.

In Germany the species is very local as well: Usually this species occurs
mainly at anthropogenic sites, because Rumex is part of the
Pionier-vegetation. The species prefers chalk-land and Rumex plants which
are exposed to full sunshine and with little other vegetation in the
neighbourhood  e.g. along roadsides,...
  
I only want to point...the population might have become so week that
collecting can exterminate it...

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Bart Vanholder
Belgian Migrant Lepidoptera Survey
Droeskouter 33
B-9450 Haaltert
Belgium
e-mail: bvholder at innet.be 
homepage Migrant Leps http://www.club.innet.be/~pub00644/
homepage Sesiidae     http://www.club.innet.be/~pub00644/sesiid/seslist.htm
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