What is the coevolution of pitcher plants?

Hmm I can think of two possible answers.





The first is competitive coevolution. How this works is that one species (the pitcher plant) starts to evolve its little trap (the bowl of liquid with slippery sides). At the same time, insects that live near these plants start to evolve ways of evading the trap (they stop liking the scent of the plant, they develop ways to get out). The plants then evolve new ways of attracting and trapping the insects. It would be like an arms race.





The second type of coevolution that you could be referring to is that in some species of pitcher plants the stuff in the bottom of the pitcher is liquid filled with insect larvae, which feed on the trapped bug and secrete stuff that the pitcher plant eats. The insects that grow in the plant and the plant itself coevolve in a mutually beneficial relationship.