At the New York Times, Carl Zimmer examines new research on the genomics of the Coffea canephora plant and the evolution of caffeine:
Plants make nectar to feed insects and other animals so they’ll spread their pollen. When insects feed on caffeine-spiked nectar, they get a beneficial buzz: they become much more likely to remember the scent of the flower. This enhanced memory may make it more likely that the insect will revisit the flower and spread its pollen further.
“How Caffeine Evolved to Help Plants Survive and Help People Wake Up“