Question

Pitcher plants have green leaves which can prepare food by photosynthesis, then why does it eat insects?

Answer 1

Hint: We can see carnivorous plants grow in acidic bog-like soils. This type of soil is quite poor in mineral salts and other essential elements for proper growth and survival of a carnivorous plant. Most plants could not survive in this type of environment because those essential compounds are leached out of the ground by the high water content. But the carnivorous plants adapt themselves over time. They have different strategies to compensate for the deficient soil.

Complete Step by Step Answer:
Now we know that insectivorous plants grow in swamps or bog areas where the soil is deficient in minerals like nitrogen. Nitrogen is an essential building block for proteins, enzymes, chlorophyll, and nucleic acids like DNA. It is a necessary element present in the soil and is absorbed by plant roots. It is also a critical need for photosynthetic and metabolic reactions important for the growth, development, and survival of the plants. The plants like pitcher plants contain chlorophyll and are green in color, so they can carry out photosynthesis to synthesize a part of the required food by themselves. But they don’t get the nitrogen from the soil in which they grow. So, insectivorous or carnivorous plants feed on small insects to collect the amount of nitrogen they need for their growth.
So, the answer is to fulfill the nitrogen content pitcher plants eat insects.

Additional information:
1) Deficiencies in nitrogen in plants are characterized by yellowish leaf color, arrested growth, and early death.
2) Each of the carnivorous plants has been seen with modified leaf structures to capture creatures and break down their bodies to extract the desperately needed nitrogen and other elements that help in the process of building enzymes, chlorophyll, and other structures and carry out photosynthesis to make their food.
3) Pitcher plants have a pitfall trap in which leaves are folded around a pool of enzymatic juices and lined with miniscule hairs that prevent prey from crawling out from the capture.
4) A few of the tropical pitcher plants are low-growing, most are climbing vines, supported by tendrils at the tips of the leaves. Some species reach 45 feet (13.7 meters) high into surrounding trees.

Note: A specific pitcher plant extract (Sarapin) collected from leaf and roots is taken by mouth for digestive disorders, diabetes, and other conditions, but there is no good scientific evidence to support these uses.