Insectivorous means insect-eating, these plants derive most of their nutrition from the insects, that they trap and consume. These plants grow in humid areas, where plenty of sunlight and moisture is found. They are found in nitrogen-deficient soil. That is why they trap and digest insects to absorb nutrients. Venus flytrap, pitcher plant and cobra lily are some of the insectivorous plants’ names. They are often called Carnivorous plants.
Let us have a brief insight into the characteristics and examples of insectivorous plants by Pritish Kumar Halder
Characteristics of Insectivorous Plants
The important characteristics of insectivorous plants are mentioned below:
They are found in the places, where there is a lack of some nutrients, especially nitrogen. They entrap insects and digest them to suffice their nitrogen requirement.
The insectivorous plants are colourful and shiny in appearance to attract insects. They often have nectars and a pleasant odour to attract insects.
Many insectivorous plants have special or modified plant parts to trap insects. The mouth of the insectivorous plants has hair-lined lined edges that snap or shut as soon as the insect touches the hair, thereby, trapping the insects. Some of the plants’ stalks are covered with sticky mucus-like substances where the insect sticks and cannot move.
Digestive Enzymes and Organisms
Some insectivorous plants secrete digestive enzymes that dissolve the insect for absorption. Others have bacteria or mites in their digestive tract that mimic the functions of the human digestive tract. They digest the prey for absorption by the plants.
Wet and Damp Habitats
The insectivorous plants are found mostly in wet, damp, humid, and acidic soil, that is deficient in nutrients, such as swamps, bogs, wetlands, coastal plains, etc. They are found in the wet regions of North America, Australia, and tropical regions.
Types of Traps in Insectivorous Plants
The leaves of the plants are modified in the form of traps. The trapping mechanisms are designated as active or passive depending upon whether they move to capture the prey or not. The different types of traps found in insectivorous plants are mentioned below:
Pitfall Traps: These are found in a pitcher plant. They comprise of a hollow leaf with a lid, filled with liquid to digest the prey.
Snap Traps: These type of traps are found in Venus flytrap. They shut their leaves rapidly as the prey touches the trigger hair.
Bladderwort Traps: These are commonly found in Utricularia. They use a partial vacuum to suck the small organisms.
Flypaper Traps: These traps are sticky and adhesive. The leaves are covered in stalked glands that secrete sticky mucilage.
Lobster-pot Traps: These are found in corkscrew plants. They possess downward-pointing hair that pushes the prey deep inside the trap.
The insectivorous plants digest the prey chemically using enzymes and bacteria. The end products of the chemical breakdown are absorbed by the plants to help them survive under unfavourable conditions.
Examples of Insectivorous Plants
Carnivorous or insectivorous plants live throughout the world. Few examples of insectivorous plants are mentioned below:
More than 200 species of Drosera are known till date. They appear to be covered in dew. This appearance is actually a sticky digestive enzyme which fakes and attracts the insects. These plants trap and digest insects.
These plants have a wide mouth lined with hair. These hair are sensitive structures. As soon as an organism touches this hair, the mouth snap shuts trapping the insect inside. Once the organism is digested, the leaves of this plant open up again to trap another prey.
Nepenthes is also known as pitcher plant. This is found generally in Asia, Sri Lanka, and Australia. This plant consists of the pitcher which produces a liquid on its own. The insects are attracted by the odour of the plant. Once the insect is trapped and produces movement in the plant, the plant starts secreting the digestive liquid. The organism is digested and the nutrients are absorbed.
These are also known as butterworts. They produce bright, colourful flowers to attract prey. They have dewy sticky leaves to trap the insects. These plants are dormant during the winter season.
It is also known as the corkscrew plant commonly grown in the wet terrestrial to the semi-aquatic environment. Genlisea contains the Lobster pot trap that has small hair lined at the entrance. It is made up of two types of leaves- the underground leaves that absorb water from the soil and anchor the plant firmly in the soil. These underground leaves form hollow tubes. With the aid of water flow, the insects enter these tubes but cannot come out.