Females will lay eggs whether a male is present or not. As with so many things snail related, availability of food affects frequency/quantity. My shrimp tank nerite female hardly lays eggs at all, but when I moved her into a fry grow-out tank that got frequent feedings, she started laying heavily again. The nerites in my community tank--where there's always an excess of food in one form or another--lay constantly.
There are male nerites, but other than segregating them and seeing who lays and who doesn't , there's really no way to tell males from females.
The eggs do eventually wear away. I've also had some success in getting nerites to lay where I want them to by providing driftwood pieces that form low arcs close to the substrate--but with enough clearance for the nerites to get underneath. Given the choice of laying in a sheltered area or out in the open, most of mine choose the sheltered spot.