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sexing larvae

Hampton Carson hampton at hawaii.edu
Mon Sep 30 16:22:16 EST 1996

I found it useful, when first learining to do this, to flatten the larva
slightly under a coverslip on the stage of a stereoscopic microscope which
has light reflected from the mirror below the stage (not too bright a
light). about one third from the rear of the larva you can see the gonad
lying in the fat body.Put a little saline under the cooverslip.  Fiddle
with the coverslip a little to roll the
larva slightly. The gonad appears as a clear transparent spot in the more
opaque fat body.  In the female, the ovary is very small and perfectly
spherical, almost identical to the typed letter "o" - the lower case o,
that is. The testis is considerably larger and more conspicuous and is
slightly ovoid, something like an Australian Rules football.I used to sex
the larvae before making salivary gland preparations. The routine was just
to flatten the larva slightly to view the gonad, using needles (once you
learn, a coverslip is not necessary). People doing this begin by saying to
themselves if you are looking for a female:"If I can't see the gonad then
it must be a female".  Actually, its very easy to be sure after you learn!

Gool Luck and Aloha from 

Hamp Carson

On Fri, 27 Sep 1996, siau min fung wrote:

> hi!! I am trying to sex 3rd instar larvae. All the protocol that I read
> tell me to look of the testes and that will be the male. I have hard time
> identify the testes and I didn't get good result. Can anyone give me some
> suggestion on sexing? 
> Thanks in advance!!
> siau min
> siauminf at uic.edu 

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