Why does the pitcher plant feed on insects even though it produces food by photosynthesis?

Q. Pitcher plant has green leaves which can prepare food by photosynthesis then why does it eat insects?

Q. You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a ‘pitcher’? How does this modification help the plant for food even though it can photosynthesize like any other green plant?

Q. Pitcher plants feed on insects to meet their _________ requirements.

Q.

You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows is shallow water or in marsh lands. What part of the plant is modified into a pitcher? How does this modification help the plant for food even though it can photosynthesise like any other green plant?

Q. Why does pitcher plant traps insects?