Why Do Little Bugs Stick to Butterworts?

Appearance

• Butterworts are small plants that grow close to the ground. They have a weak root system used to anchor the plants to the soil and take up moisture. The plants rely on carnivory of insects to obtain the nutrients needed to develop healthily. The leaves are often curved upward, which helps funnel the nutrients of their insect prey into the base of the plant. Butterworts develop a single flower on a tall flowering stalk that remains high above the foliage of the plant. Butterworts develop yellow, violet, white and blue flowers, depending on the species.

Structure of the Leaves

• The upper leaf surface of butterwort foliage is covered with two specialized glands that trap and digest insect prey. The peduncular glands are tall, upright structures that produce a sticky, greaselike mucilage that covers the surface of the foliage and gives the plants a slippery feel, hence their common name "butterwort." The leaves also contain several smaller structures called sessile glands that release digestive enzymes when a small insect is trapped in the mucilage.

Function of the Leaves

• The wet appearance of butterwort foliage attracts small insects looking for water. Some insects are also attracted to the scent and color of the flower. When the insect lands on the leaf surface, it is covered by the mucilage. As the insect struggles to get free, it triggers nearby peduncular glands, which release more mucilage and firmly trap the insect. Once the insect is trapped and exhausted, butterworts excrete digestive enzymes and absorb nutrients from the insect, fueling new plant growth to attract and trap more small insects.

Importance

• Butterworts often grow in nutrient-poor habitats such as marshy bogs, rock crevices and sandy intertidal zones. The carnivorous nature of these plants allows them to obtain nutrients and thrive where few other plants can survive. Although some species of butterworts are protected by law on public lands, due to their interesting biology and low populations, several species are readily available from plant nurseries and are easy to grow indoors.