Originally Posted by NigelN

From my experience with other species (Clarkii and Cherax), just because they mate doesn't mean the female will berry. I've seen my Clarkiis mate on two occasions but no berry. My Cherax, didn't see them mate but one day the female started keeping her tail tightly curled under her body and then after 2 weeks eggs appeared. So I'd say just keep the water quality good, enough food and hiding places and they would do what they naturally do.

Perhaps increasing to two males and two females might increase the chance of mating. Also must be careful not to buy lobsters from the same batch because they most likely are siblings and inbreeding will occur resulting in weak genes and problems with the offspring (same reason why marriage into the family and amongst cousins are frowned up).