Cicada egg laying

I came across to the scenery of egg laying by a female cicada in the evening. This is my first experience and it was recorded for a few minutes.
Specific marking on the branch surface attached at equal intervals was observed, judging from it's attitude, an egg must be invested there one by one.
Careful checking reveled that such kind of markings were found on several branches. Female one succeeded in mating had done it?
A few years later, next generation would come out on the ground and do the same----, so I hope.
An ant is fighting on secretion fluid, but not on the cicada itself. I wanna know that how an ant can tell a cadaver and living one?
It must have a capability to catch special odor due to protein degeneration?