Dave,
You may get all kinds of answers, but the most definitive paper I've seen on Tilapia is at this location:
http://srac.tamu.edu/tmppdfs/6047018-283fs.pdf In my experience, this paper is right on the mark.
Reproduction does not occur below 68 degreees and kind of gradually increases up to 80 degrees which is optimal. My fish are spawning now in East Texas, making beds in shallows...haven't seen any fry but they carry the eggs and fry in the female's mouth for several days. My water temps were 74 last weekend and on the rise. Every little cold snap drives them back out of the shallows however...but it looks like that is mostly past now.
You should begin seeing them right away in the shallows, doing their thing. Soon after, little Tilapia will show up, but are quickly mostly eaten by your bass. Its wonderful, absolutely wonderful. What a fish!
