Cobra Plant Insect Trap

One of the most interesting areas of botany is the functioning of plants that don’t rely on photosynthesis to survive. Recent studies of the California pitcher plant (Darlingtonia californica), also known as the cobra plant because of its shape, have shown that its design is incredibly complex.

David Armitage at the University of Notre Dame has been studying this plant, and in a recent article in Science News (January 21, 2017, page 4) he reported on what is known about this strange plant. It grows in soil rich in serpentine which would kill most photosynthetic plants. The cobra plant survives by being “meat dependent.” Up to 95% of the nitrogen the plant uses comes from insects trapped inside the leaves of the plant.

The curled leaves of the California pitcher plant serve as an insect trap. It draws insects into the leafy trap by secreting a sweet substance. This secretion is not through its blossoms but from a special roll of tissue near the mouth of the insect trap. When an insect enters the small opening under the cobra-like head of the pitcher, something interesting happens. By a method still not understood, the cobra plant draws water up from the soil and creates a pool in the bottom of the “pitcher.” Putting other substances into the trap doesn’t trigger the water. The plant will only respond to an insect. How the plant knows what is a bug and what isn’t a bug is still not understood. The water contains bacteria which lower the surface tension, so when a bug falls in, it quickly sinks to the bottom and drowns.

Another unsolved mystery of this plant is that it has a forked tissue at the top of the trap called a “fishtail” which resembles a mustache with red veins. It does not lure insects into the plant, but its function is still not understood. Armitage says “The only thing fishtails lure, for the time being at least, are puzzled botanists.”

Those of us who see God’s designing hand in the natural world would see the cobra plant as a special design to meet a particular environment. We would point to the Bible in Romans 1:20 where it says, “We can know there is a God through the things he has made.” The complexity of the California pitcher plant supports such a viewpoint in a special way.
–John N. Clayton © 2017