Pitcher plant grows in nitrogen deficient soil, and it derives its nitrogen content from the insects.
The insects get attracted towards the pitcher plant because of colourful lid and nectar. As the insect lands on the plant, the neck of the pitcher closes and the bristles inside the pitcher pierces the body of the insect. The insect cannot escape as the pitcher is filled with slippery and acidic fluid. Once the insect is trapped, the insect is digested.