So maybe it makes sense to speak with your plants ; )
Anyway don't find it that surprising. Basically it seems a natural advantage to have such warning mechanism.
Cleve Baxter did a lot of research on this, and his experiments were even featured on an episode of myth busters. His research indicated that plants can sense a humans intentions. He figured this out by attaching polygraphs to plants and then directing negative thoughts towards the plant (cutting, burning etc.). The polygraph then went haywire, but when he thought nice things about the plant the polygraph stayed normal.
Isnt plant communication an active field of research ? I remember reading about how plants in a field can communicate changes in environment (like a bug infestation) with one another.
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