Picture plant has leaves on it, …

• Plants that eat insects are called insectivorous plants. They trap and digest insects. Pitcher plant is the example of an insectivorous plant. 
• The soil of marshy land is deficient in nitrogen. Plants living in marshy areas do not get nitrogen from the soil. To fulfill their nitrogenous needs, they need to eat insects.

Plants like pitcher plant are green and carry out photosynthesis to obtain a part of the food required by them. But they do not get the nitrogen from the soil in which they grow. So, insectivorous or carnivorous plants feed on insects to obtain the nitrogen needed for their growth. Once they obtain the nitrogen, the carnivorous plants are able to build enzymes, chlorophyll and other structures and carry out photosynthesis to make their own food. ... And, unlike carnivorous animals, carnivorous plants do not capture prey for food energy… but just for the required building blocks.