Entangled Life: When broad bean plants are attacked by aphids...

"Plants omit all sorts of chemicals. When broad bean plants are attacked by aphids, they release plumes of volatile compounds that drift out from the wound, and attract parasitic wasps that pray on the aphids. These info-chemicals are one of the ways plants communicate, both between different parts of their own bodies and with other organism"

— Entangled Life, Merlin Sheldrake