The waterwheel plant, or Aldrovanda vesiculosa, is innoxious-looking but certainly isn’t as benign as it seems. This plant is more like the venus flytrap than seaweed, as it hunts small animals. The waterwheel plant used to have 19 variations, but it is now a single species.

Featured image credit: Denis Barthel (CC BY-SA 1.0)


Appearance

The carnivorous waterwheel plant is an interesting aquatic plant as it has no root, and its stems float in the water. These stems can reach up to 40cm in length.

The waterwheel traps float using air sacs and have two lobes. These come together to create a snappy trap. This trap closure can happen as quickly as 10-20 milliseconds, making it near impossible for its prey to escape in time. The plant uses fine hair-like triggers on the trap to detect any potential prey as it passes. Once these hairs make contact with an invertebrate, the trap snaps shut, capturing its food.

The Waterwheel plant uses its hair-like fibers to trap its prey
The Waterwheel plant uses its hair-like fibers to trap its prey

Credit: Denis Barthel (CC BY-SA 1.0)

Habitat

The waterwheel plant is one of the most widely distributed carnivorous plants on earth. They can be found natively in Asia, Africa, Australia, and Europe. However, despite the spread of the waterwheel plant, the populations have dwindled and even become extinct in various parts of the world. The plant is normally found in wetland habitats, ponds, and lakes.

When the plant is thriving, it tends to favor exposure to light in shallow, clean, warm, standing water. It also needs to be located in water with the correct acidity.

Diet

The waterwheel plant is a carnivorous plant and feeds primarily on small invertebrates. It uses its snap trap to capture passing small aquatic creatures. Some of these creatures include eelworms, daphnia, tadpoles, and small fish.

Reproduction

In order to reproduce, the waterwheel plant leaves its flowers above the water. These flowers then open for a few hours at a time. Once fertilized, the flowers then come beneath the water to allow the seeding process to take place. The seeds are supported by cotyledons, which allow for the seed to get the energy it needs to fruit.

However, the temperature has to be right for the seed production to take place. The reproductive process they engage in is vegetative reproduction. This is where new offshoots of plants are continuously produced every so often, allowing for the species’ rapid growth.

The waterwheel plant also has an interesting strategy to deal with different weather conditions. For example, it will utilize turions, or underground buds, to protect itself from the winter weather. They will sink under the water level to the bottom, where the temperatures are warmer. In the winter, the waterwheel plant will grow at a slower rate and produce non-carnivorous leaves until the temperature is more favorable.

The waterwheel plant is mostly found in freshwater ponds and lakes
The waterwheel plant is mostly found in freshwater ponds and lakes

Credit: Daiju Azuma, CC BY-SA 2.5


Threats

The waterwheel plant has a critically endangered conservation status. The IUCN has listed the plant at this level due to the rapid decrease in its population. Although it spans a wide variety of places, the numbers are lowering significantly.

The fact that it is an endangered species is of great concern to biologists, as they play a vital role in the ecosystem of many ponds and lakes.

Facts about the Waterwheel Plant

  • The waterwheel plant feeds on small aquatic creatures, such as small fish, tadpoles, and eelworms.
  • They can be found on the majority of continents on earth, but in low numbers.
  • There used to be 19 species of the plant, but now only one exists.
  • The trap catches its prey in 20 ms, making it an effective hunter.
  • They can adapt to different weather conditions and seasons.


FAQs

What does the waterwheel plant eat?

The plant is carnivorous and feeds on small aquatic invertebrates. These include tadpoles, small fish, eelworms, and daphnia.

Where does the waterwheel plant grow?

The waterwheel plant grows across many continents but in small numbers. Currently, they are seen in Europe, Asia, and Australia. However, it used to live in Africa also.

Why is the waterwheel plant endangered?

The waterwheel plant is listed as critically endangered on the IUCN list. This is due to habitat loss, mainly from human actions.

Is the waterwheel plant an invasive species?

Despite its fragile status across the world, in North America, the waterwheel plant is thriving. It is considered an invasive species in New Jersey and New York.