- Sundews capture insects on their leaf glands.Jupiterimages/Photos.com/Getty Images
Carnivorous plants require few nutrients from the soil, making them a suitable addition to the low fertility environment in most terrariums. The plants instead receive most of their nutrients from the small insects they capture and digest. They use a variety of methods to capture these insects, depending on the variety of plant.
- One of the most well-known carnivorous plants, the Venus flytrap has a hinged trap that closes and traps its prey inside. It feeds on small flying and crawling insects. Once trapped, the insects are dissolved and the nutrients extracted for the plant's use. Flytraps thrive in warm, moist conditions, such as those provided in a closed or partially closed terrarium. When grown in a completely closed terrarium, insects must be provided for the plant to feed.
- Pitcher plants, or sarracenia, have modified leaves shaped as funnels or pitchers. Appealing nectar sits in the bottom of each pitcher, enticing the insect prey inside. Once inside, the insect is trapped and the plant then dissolves the insect to extract the nutrients. Pitcher plants only grow wild in North America, preferring moist, boggy areas. They can be grown in open terrariums indoors as long as you provide lots of sunlight and warmth.
- Instead of a trap, the sundew has long leaves with a sticky gland on the tip of each. The glands glisten in the sun, earning the sundew its name. Insects are drawn to the glands and trapped. As they struggle, nearby leaves and glands move toward the prey and trap it further. Smaller sundew varieties thrive in the closed conditions of a terrarium as they require plenty of warmth and high humidity to grow. The larger types are too big for most terrariums and can only be grown outdoors.
- The leaves of the butterwort plant feel slightly greasy and sticky. This sticky covering traps the insects, then the struggle of the prey signals the plant to produce its digestive enzymes. These plants thrive in humid, warm environments, such as those found in closed terrariums. Butterworts prefer to feed on aphids, though they can also feed on other small insects. In closed terrariums, you must provide insects for the plants to capture.