sex determination

[Dalius Dapkus]

Dear Andrea,

I am not a genetic specialist but I know that most of insects have 
such sexual chromosomes:
females - XX, males - XY.
But SOME SPECIES of Lepidoptera (I do not know how many) have:
females - XY, males - XX sexual chromosomes.
So logically sex is determined after copulation and when an egg is 
formed. I do not know any facts that any other factors could 
determine the sex.

Dalius Dapkus


> Hi all,
> 
> does anybody klnow when the sex of a butterfly is determined? Is it 
> set in the egg right after laing? Or is it possible to change the sex by 
> e.g. temperature after the egg is laid like in some fish?
> 
> Thanks in advance,
> Andrea Knebel
> University Bielefeld,
> Germany
> 
>