[leps-talk] Re: Inducing Oviposition

[Robert P. Dana]

Tried the other day to post my two cents worth on this thread to the 
TILS-Leps-Talk list, but for some reason Yahoo decided that I was not 
a subscriber. Since then I think others have suggested that the idea 
that butterflies are "forced" to oviposit by the relentless 
maturation of ova is not necessarily true. But my comments may still 
be interesting to some.

Robert Dana


>----- Original Message -----
>From: <guy_vdp at t-online.de>
>Sent: Thursday, May 23, 2002 6:59 AM
>Subject: Re: [leps-talk] Inducing Oviposition
>
>
>>  The same works for Pierids,
>>  I'd like to add that I usually feed the female using a forceps to hold
>her
>>  by the wings and a preparation needle to unroll her tongue.
>>  Usually grape-juice works well, I always have some in the deep-freeze as
>>  ice-cubes, there are better recipes for this, but the juice is readily
>>  available and works good enough for me.
>>  The advantage of this is that the female 'has' to lay eggs (because of
>the
>>  food supplies her body continues to make eggs - the fresh ones will
>'push'
>>  the older ones out of her body).
>>
>  > Guy.
>
Back in the 80s I worked on various aspects of the biology of 
Hesperia dacotae here in MN. I needed lots of ova, and so held 
field-caught females in small cages set out in the prairie. Because I 
was interested in total potential fecundity, I dissected many 
specimens at various points in their egg-laying life, from newly 
emerged (reared) individuals to very worn, nearly depleted 
individuals that I had held in a cage for many days (removing eggs at 
the end of each day and keeping a tally). By the way, the data are 
summarized in my thesis. The point of interest here is that it 
appeared to me that females of this species are capable of exercising 
some control over the maturation of ova in their oviducts. Newly 
emerged females had only a small number of fully mature ova, and if 
they did not mate, this number did not increase for several days. It 
also appeared to me that mated females slowed down the rate of 
egg-maturation when several successive days of inclememt weather 
occurred. As this was not a focus of my research, I did not conduct 
these observations according to a strict protocol, so these are only 
impressions.

Robert Dana
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