Plants communicate using fungi
When some plants are attacked by aphids they can defend themselves by releasing ‘volatiles’ into the air, chemicals that repel aphids and also attract wasps, which are an enemy of aphids. If plants could tell each other when aphids are attacking, they could release their volatiles earlier and thwart the attack. It turns out that they might be doing just that.
But how are they communicating? It’s not quite clear yet but it appears to be through a fungal network that infiltrates plant roots. Therefore, the fungi might be operating as a diffuse multi-organism nervous system.