Published: 5 March, 2008

Venus flytraps' carnivorous ways enable it to do photosynthesis better

Is a venus flytrap a producer or a consumer?

The Venus flytrap (Dioneae muscipula) is one of about 600 species of carnivorous plants. Insects and spiders are the most common "prey" for these "meat-eating" plants, but they will occasionally capture small amphibians or mammals. Many of these plants are as well known for their unusual appearance - the somewhat mysterious-looking appendages that are used to capture prey - as they are for the fact that they can eat meat. The fact that these plants capture animals as prey raises the interesting question: Are the Venus flytrap and its carnivorous relatives biological producers or consumers?

Producers are most commonly organisms, plants and algae that use photosynthesis to convert simple compounds like carbon dioxide and water into the "stuff of life" such as carbohydrates and proteins. Consumers are incapable of this conversion magic; they must obtain their food by eating plants or animals that exist by eating plants. In this sense, the answer to your question seems clear - the Venus flytrap is both a producer and a consumer. As a plant, it produces its body by doing photosynthesis, but it can also supplement its growth by consuming meat. Let's consider this balance between producer and consumer in a bit more detail. Specifically, since it already has the ability to do photosynthesis, what benefit does a Venus flytrap obtain from its carnivorous lifestyle?

One way to approach this question is to look at the natural habitat of the Venus flytrap and its carnivorous relatives. Carnivorous plants are most commonly found in bogs - places where water and sun tend to be plentiful but soil nutrients are scarce. In order to grow, plants need sunlight, water and carbon dioxide, but they also need soil nutrients as sources of nitrogen, phosphorus, iron and other trace compounds for their growth. If these nutrients are in short supply, like in bogs, plant growth is limited.

Carnivorous plants have evolved a way to supplement the meager supply of nutrients available in bog soils by capturing insects and other small prey. In reality, the vast majority of the materials (atoms?) that make up the body of a carnivorous plant are derived from photosynthesis with only small amounts coming from the insects that the plant digested. At the same time, the acquisition of extra nutrients through its carnivorous lifestyle permits the flytrap to carry out significantly more photosynthetic growth than its non-carnivorous neighbors. This permits the flytrap to successfully compete in a habitat where its growth would otherwise be limited. Thus the flytrap is first and foremost a producer, but it can increase its photosynthetic growth through the nutrients it obtains from the prey it captures.