Subject: Does slug reproduction depend on photoperiod?

I am doing a research project where I am trying to "mate" slugs in order to 
study the offspring.  I have found information on how the slugs reproduce and 
how they will lay their eggs in small clusters, but have not been able to find 
information on what triggers the slugs to "breed".  Also, I was wondering how 
large an individual egg will be?  Will it be visible to the naked eye?  Thank 
you.  

Re: Does slug reproduction depend on photoperiod?