Carnivorous Plants: Plants that Hunt
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals typically insects. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic bogs and rock outcroppings.
Five basic trapping mechanisms are found in carnivorous plants.
1. Pitfall traps (pitcher plants) trap prey in a rolled leaf that contains a pool of digestive enzymes or bacteria.
2. Flypaper traps use sticky mucilage.
3. Snap traps utilize rapid leaf movements.
4. Bladder traps suck in prey with a bladder that generates an internal vacuum.
5. Lobster-pot traps force prey to move towards a digestive organ with inward-pointing hairs
Pitcher plants are carnivorous plants whose prey-trapping mechanism features a deep cavity filled with liquid known as a pitfall trap. Flying or crawling insects such as flies are attracted to the cavity formed by the cupped leaf, often by visual temptations and nectar bribes. The sides of the pitcher are slippery and may be grooved in such a way so as to ensure that the insects cannot climb out. The small bodies of liquid contained within the pitcher traps drown the insect, and the body of it is gradually dissolved.
The Venus Flytrap, is a carnivorous plant that catches and digests animal prey—mostly insects. Its trapping structure is formed by the terminal portion of each of the plant's leaves and is triggered by tiny hairs on their inner surfaces. When an insect or spider crawling along the leaves contacts a hair, the trap closes if a different hair is contacted within twenty seconds of the first strike.
If the prey is unable to escape, it will continue to stimulate the inner surface of the lobes, and this causes a further growth response that forces the edges of the lobes together, eventually sealing the trap hermetically and forming a 'stomach' in which digestion occurs. Digestion is catalyzed by enzymes secreted by glands in the lobes. Digestion takes about ten days, after which the prey is reduced to a husk. The trap then reopens, and is ready for reuse.
Sundews comprise one of the largest genera of carnivorous plants. They capture, and digest insects using stalked mucilaginous glands covering their leaf surface. The insects are used to supplement the poor mineral nutrition that sundews are able to obtain from the soil in which they grow.
Sundews are characterized by the glandular tentacles, topped with sticky secretions.. Small prey, mainly consisting of insects, are attracted by the sweet secretions of the peduncular glands. Upon touching these, the prey becomes entrapped by sticky mucilage which prevents their escape. The plant meanwhile secretes enzymes. These enzymes both dissolve the insect and free the contained nutrients. The nutrient soup is then absorbed through the leaf surface and can then be used to help fuel plant growth.