The take about a month I believe to lay eggs and it will be about two weeks before you start seeing babies . It depends on your tempature and elevation tho . I live at 7000+ ft and have them at room tempature .
Be sure to separate the beetles from the worms tho or else the beetles will eat all your new worms !!
Once the beetles turn black they are ready to mate, so say 2 weeks to mate, one week to lay egg, and another 2ish weeks to hatch. Everything depends on temps tho!