Why Do Carnivorous Plants Trap Insects?

Pitcher plants eat insects and can be attacked and damaged by insects in the wild.

Like other plants, carnivorous plants need nutrients to survive. However, carnivorous plants live in poor soil conditions, where there are no nutrients in the soil. Therefore, the meat-eating plants secure the nutrients needed from insects.

Trapping

Carnivorous plants have active traps, semi-active traps and passive traps. Venus flytraps are active traps because the two leaves close on the insect. Passive traps capture the insect, but have no mechanical moving parts. The pitcher plant has a passive trap: a pouch that trap insects inside. Semi-active traps such as the sundew have tiny sticky droplets that hold the insect in place while the leaf slowly curls over the insect.

Nutrients

After trapping the insects, the carnivorous plants dissolve the insects to get the nutrients needed. Carnivorous plants have digestive enzymes that aid in the digestion process of the insects. As the digestive process proceeds, the plant absorbs the nutrients.

Insects Retaliate

Not only do carnivorous plants eat insects, but some insects attach and can feed on the plants. Carnivorous plants are subject to attack from aphids, black vine weevils, caterpillars, fungus gnats, mealy bugs, snails and slugs. In rare cases, grasshoppers and katydids can chew on the leaves of the carnivorous plants.

References

• International Carnivorous Plant Society
• Botanical Society of America: Carnivorous Plants/Insectivorous Plants