Plants apparently scream when attacked by caterpillars, alerting nearby plants, and release a substance into the air to attract birds to come and eat them!!!
Much more in Video.
0:00 Plants talking to each other
0:45 Types of plants communications
1:30 Volatile compounds released by plants
2:20 What these compounds do
3:20 e.g. nicotine
3:45 Volatiles used in communication
4:15 How this was achieved
5:25 What proteins were used
5:50 How leafs react
6:30 Why are they doing this though?
7:30 Conclusions
h/t Mad Kelly