How Do Carnivorous Plants Catch Their Prey?

Carnivorous plants survive by attracting, capturing, killing and digesting prey.

Carnivorous plants are predator plants that survive by attracting, capturing, killing and digesting prey such as insects, crustaceans and spiders. Some plants also eat rats, lizards, mice and other such smaller vertebrates. The evolution of carnivorous plants is attributed to poor soil conditions, forcing plants to prey on insects and other small creatures for nutrition. The ways in which carnivorous plants catch their prey can be divided into two broad categories--active trapping and passive trapping, according to University of Florida Extension. In an active trap, the prey must trigger a mechanism for the trap to close; a passive trap catches any hapless insect that falls in.

Pitfall Traps

The pitfall trap is the most common method by which carnivorous plants catch their prey, according to the University of Maryland Department of Life Sciences. Pitcher plants have deep, cup-like leaves, which fill with rainwater and the digestive enzymes produced by the plant. The plants attract insects using scent, nectar and color. The nectar is located to facilitate trapping, as attractive insects fall into the pit when trying to drink the nectar. The upper portion of the leaves is slippery, not allowing the prey to escape. Once inside the pit, the prey is captured by hairs pointing downwards. The prey drowns in the mixture of water and enzymes and are eventually absorbed by the carnivorous plant.

Flypaper Traps

Carnivorous plants such as byblis and Venus flytrap use flypaper traps to capture prey. The leaves of these plants consist of glands filled with a sticky substance that looks like nectar to attract insects. Along with this the plant gives out a unique odor that also helps in attracting prey. When an insect or any other small creature sits on the leaves it gets entangled in the sticky fluid. The insect dies trying to escape and is then "eaten" by the plant.

Bladder Traps

Bladder traps are used by plants such as bladderworts. The plants consist of small openings with a door-like structure. When stimulated by a prey, it is sucked inside due to the vacuum created inside the trap. The prey is then killed and digested by the plant.

Snap Traps

As the name suggests,a snap trap suddenly closes, trapping the insect inside like a mouse-trap. The trap is a modified leaf which is stimulated when prey enters. The leaf then suddenly shuts. The prey is then killed by the hair on the inner surface of the trap. The trap remains closed till the insect is digested by the plant. A snap trap works only three to four times and then dies.

Lobster-Pot Traps

A lobster-pot trap is the most uncommon method by which carnivorous plants catch their prey, according to the University of Maryland. There are just 35 species of carnivorous plants that use this method. These are generally found in South America and West African. Lobster-pot traps capture their prey as they are easy to enter, but difficult to leave, according to the University of Missouri's "Environment & Garden" January 2008 newsletter. Directional hairs inside the trap keep the prey keeps moving towards the digestive mechanism of the plant as they attempt to escape.

References

• University of Florida: Fact Sheet—Carnivorous Plants-Bog Garden
• University of Maryland: Carnivorous Plants and Their Prey Pollinators and Peculiar Partners
• University of Missouri: Carnivorous Plants