Subject: Re: Catching females

From: [email-masked] (Pierre le Roux)
Date: Sun, 24 Nov 1996 16:13:35 GMT

[email-masked] (John Clayton) wrote:

>In article <[email-masked]>, Charles Nicholls <[email-masked]> writes:
>> Hi all,
>> 
>> can anyone tell me which is the best way to catch female
>> moths(British).  I have been collecting data over the past two
>> summers using a couple of large mercury vapour traps but these tend
 
>I have read Paul Opler's comments on this.  I do not know anything of the
>difference between UV and MV in this respect.

>There is however, one thing that I have noticed very clearly, and I
>wonder if this is a well-known phenomenon.

>For many years I trapped in Scotland, and found that the overwhelming
>majority of individuals were male.  This was especially the case
>for the Noctuidae.  When I moved to a tropical environment I found
>this was not the case.  In fact in some groups I find many more
>females.

>The explanation suggested to me has been the following.  Adult females
>require a higher energy intake for the development of eggs.  In a
>relatively cold climate, this means that they have to conserve as much
>as possible, and hence don't fly much.  This is less relevant in
>a warmer climate.

>John Clayton.

It would be interesting to note when the traps (time of night) were
lit. A local study (in the sub-tropics) done in 1970' s indicated that
the females were more often trapped earlier in the evening, (before
10pm) and the males later, around 02h00. The explanation given was
that the females did most of the ovipossition during early evening,
with the males flying later to the pheromones of  newly emmerged
females. This study was done for  the Saturniidae.