Stefano Mancuso studies what was once considered laughable - the intelligence and behaviour of plants. Mancuso's lab started work in 2005. We were interested in problems that were, until that moment, just related to animals, like intelligence and even behaviour," he says. At the time, it was "almost forbidden" to talk about behaviour in plants. But "we study how plants are able to solve problems, how they memorise, how they communicate, how they have their social life and things like that". One of the most controversial aspects of Mancuso's work is the idea of plant consciousness. "Let's use another term," Mancuso suggests. "Consciousness is a little bit tricky. Let's talk about awareness. Plants are perfectly aware of themselves." A simple example is when one plant overshadows another - the shaded plant will grow faster to reach the light. But when you look into the crown of a tree, all the shoots are heavily shaded. They do not grow fast because they know that they are shaded by part of themselves. "So they have a perfect image of themselves and of the outside," says Mancuso. Far from being silent and passive, plants are social and communicative, above ground and beneath, through their roots and fungal networks. They are adept at detecting subtle electromagnetic fields generated by other life forms. They use chemicals and scents to warn each other of danger. When corn is nibbled by caterpillars ... the plant emits a chemical distress signal that lures parasitic wasps to exterminate the caterpillars.