At 28 I am finally able to keep house plants alive; and considering rewarding myself by taking in a carnivorous plant. The Cape sundew (Drosera capensis) is originally from South Africa but is now a widespread domestic plant.
More dramatic than the pitcher plant or even the Venus flytrap, the Cape sundew captures its prey by rolling it up in a sticky tentacle-covered leaf (see animation). It also has the added benefit of being reasonably priced. The one problem is that I am living in a high rise apartment with literally no insect life.
Carnivorous plants don’t derive all their nutrients from flesh, but rather supplement with photosynthesis. But how much of each do they really need? Does it matter if my potential new plant was a vegetarian (photovore)?
It turns out that carnivorous plants are the result of convergent evolution— that is, evolution came up with this solution multiple times in different evolutionary lines. Wherever they are in the world, carnivoreous tend to grow in sunny, wet or otherwise nutrient-poor environments. Developing carnivorous ways is not exactly easy for a plant, so it follows that these plants had a lot to gain from developing new feeding strategies..
The Cape sundew’s tentacles, sticky mucus used to trap prey, and digestive enzymes used to devour it (excreted over a period of hours) are not very photosynthetically efficient. Not to mention the energy expenditure to send more water through the “veins” to move all those trapping tentacles. However, studies show that terrestrial carnivorous plants don’t really get that much nutrients from their prey—, definitely not enough to survive. However, even in the haven of my apartment, a Cape sundew plant can derive benefit from eating meat.
What the little plant is really after is the phosphate contained inside its prey. Unlike animals, plants don’t build their matter with carbon and proteins which we gain when we eat a steak (or bugs
With phosphate coursing through its system, the plant will photosynthesize at nearly twice the rate it would without an insect snack while still eating like a plant: directly from the sun.
Andrej Pavlovič1, Miroslav Krausko, Michaela Libiaková and Lubomír Adamec. “Feeding on prey increases photosynthetic efficiency in the carnivorous sundew Drosera capensis.” Annals of Botany. Volume 113, Issue 1, p. 69-78.
Givnish TJ, Burkhardt EL, Happel RE, Weintraub JD. Carnivory in the bromeliad Brocchinia reducta with a cost/benefit model for the general restriction of carnivorous plants to sunny, moist, nutrient poor habitats. American Naturalist 1984;124:479-497.