Hi fishermen and women.

I have never fished egg paterns, the reason is I don't know why I should.

My question is, why eggs?
Do they drift in the stream, are they a part of trouts natural food?
Does a similar thing happen in lakes.
Do trout go after the eggs on the bottom also?

How does this "egg thing" work, or so to speak?
How to fish, where to fish.
How effective are they and i some season better than other (autumn of course?).

Regards,
Thorarinn