[thaumasiotes]

This is basically the same as arguing that exposure to sunlight won't darken your skin, but it will mean that natural selection gives your descendants darker skin.

There is every reason to expect that a plant's defenses against predation will be more active the more predation it experiences.

[ricardobeat]

Melanin is produced as a reaction to UV exposure. Capsaicin is not produced as a reaction to bug bites. This is basic Darwinism vs Lamarckism, evolutionary pressure vs the idea of inheriting acquired traits.

[thaumasiotes]

You just stated that you didn't know whether or not this was the case. Has that changed?

> This is basic Darwinism vs Lamarckism, evolutionary pressure vs the idea of inheriting acquired traits.

Considering we're only talking about one plant, and not an ancestral line of plants over time, you appear to be pretty badly confused.