Carnivorous Plants: Skipping the Insects for a Second Helping of Pollution

Human’s destructive practice of burning fossil fuels is leading carnivorous plants to switch their diet. While examining the common sundew drosera rotundifolia, a plant native to Swedish bogs, scientists from England’s Loughborough University found that scores of the small plant were eating less insects (their “meat” source) and were rather getting their fill off of pollution.

Plants like the common sundew derive much of their necessary nitrogen from insect-based sources. To get their food, the plant secretes a sticky mucous-like substance from the glandular hairs on its leaves; insects are then attracted to the hair’s bright color and sweet taste and end up becoming caught on the surface. As the insect dissolves into the plant, the common sundew absorbs all the necessary nitrogen. While most non-carnivorous plants are able to soak in nitrogen from the ground, plants like the common sundew have had to adapt in order to live in areas where nitrogen levels are less available.

Nitrogen (a byproduct of industry) reaches soil after being released from factories and other fossil fuel burning devices; it is then soaked up in clouds and eventually rained back down onto the earth and soaked into the ground. In areas highly affected by fossil fuel pollution, nitrogen accumulates in the ground and makes its way to the roots of a variety of plant life. Nitrogen levels in the soil become high and can disrupt the normal processes of the vegetation dependent upon it.

After collecting numerous samples of the common sundew, researchers were able to determine how much plant’s nitrogen intake came from insect-based sources and how much came from the nitrogen-infused soil. The two could be differentiated because nitrogen from insects has a different makeup of isotopes than nitrogen that has fallen down in rain. According to their findings, insect-based nitrogen only made up about 22 percent of the common sundew’s nitrogen levels, compared to the control group’s (plants will significantly less pollution interference) 57 percent.

And the issue here goes deeper than the plants simply skimping out on the occasional meal. Besides eating fewer bugs, the plants are beginning to change its form to better adapt to its changing (and more nitrogen-enriched) environment. The sticky substance that acted as the plant’s insect trap is becoming less and less sticky, and the bright attractive red color is beginning to turn green—this would suggest that the plant is gearing up for photosynthesis, and not capture and kill. “If there’s plenty of nitrogen available to their roots, they don’t need to eat as much,” explained Dr. Jonathan Millett from Loughborough University, and head author of the study.

But what does this mean for the environment? Well it could mean a slew of things: first, it could that the common sundew, and other carnivorous plants like it, may fall back to its vegetarian ways—pre-evolutionary change that brought it to wear it is no—thus eliminating its species-specific trick. The switch away from meat-based nutrition could also be an example of how inefficient nutrient consumption through animal-based means can be. Yet, what is certain is the fact that our industrialized ways are making a profound impact on the world in which we live.


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