About Carnivorous Plants
What are Carnivorous Plants?
Carnivorous plants are plants that are specially adapted to get some or most of their nutrients by catching and consuming prey. They are sometimes also called ‘insectivorous plants’ because they most often catch insects and other arthropods, but some prey on tiny single-celled organisms and others can occasionally trap larger animals such as small mammals and amphibians.
Carnivorous plants generally live in places where the soils lack important nutrients, especially nitrogen and phosphorus. Many grow in acidic bogs, but others live in tropical rainforests, on mountaintops or even in dry, sandy soils. By catching prey they are able to thrive in conditions where many other plants would struggle to survive.
The Venus Flytrap Dionaea muscipula is familiar to most people, but there is a huge variety of lesser-known carnivorous plants. Carnivory is believed to have evolved independently at least 12 times in different plant families. There are currently more than 600 known carnivorous plant species. In addition, perhaps another 300 or so species are considered ‘proto-‘ or ‘para-carnivorous’.
‘True Carnivores’ and ‘Proto-carnivores’
There is no single definition of precisely what makes a plant ‘carnivorous’, but most experts agree that a true carnivorous plant should show adaptations that:
- attract prey,
- catch and retain the prey,
- cause the dead prey to be digested, and
- absorb the resulting nutrients to benefit the plant.
Plants that show some, but not all of these traits may be considered ‘proto-carnivorous’ or ‘para-carnivorous’. One common area of disagreement about what makes a true carnivorous plant is whether the plant secretes its own digestive enzymes, or relies on other organisms such as bacteria to digest prey. Another is to what extent the plant benefits from prey or relies on it for success.