In the 1987 film The Last Emperor, Pu Yi is removed from power and taken away from the Forbidden City. As a child, he had a pet cricket that he kept in a tiny cage in a secret compartment in his throne. Pu Yi returns as an adult and finds the (60 year old!) cricket alive and well in the secret compartment in the old throne. How did that work? Did he imagine the cricket to be alive, or was there somebody behind the scenes that maintained the old throne and its tiny resident(s) so that there was always a live cricket in the cage inside the throne? Or is there another explanation?
Crickets are not long-lived, with a lifespan of only around three months. The use of the insect is symbolic. The cricket was kept as a pet in a cage, a situation not unlike Pu Yi's, as he was caged within the Forbidden City. The symbolism of the cricket in the final scenes could be interpreted in a multitude of ways:
It's up to the audience to decide which interpretation is the best fit. But what is certain is that the scene is symbolic.