Carnivores capture the imagination, and doubly so when the creature is a plant. Dealers do a land office business selling Venus flytraps, sun dews, and pitcher plants. But why would a plant become a flesh eater? After all, except for a few parasites, plants manufacture their own food through photosynthesis. Unfortunately for plants, certain chemical elements are necessary to carry out photosynthesis and other life processes. One such is nitrogen, in extremely short supply in some habitats. Most carnivorous plants live in bogs where nitrogen is at a premium, but available in the bodies of animals.
The mechanisms used by the plants we've mentioned are known to most
people, but a different group of carnivorous plants, the bladderworts, use a unique
technique. A bladder closed by a trap door is sprung open when prey touch sensitive
hair-like structures. The result? Low pressure within the sac sucks the animal in, and
the trapdoor slams shut. Maybe in time our region will develop such carnivores, for
desert plants, like those of bogs, compete viciously for that limiting resource,
nitrogen.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
>Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.