Weird carnivorous flower devours worms underground

Jeremy Hance
January 09, 2012

Scanning electron microscope image shows the upper leaf surface of Philcoxia minensis. Arrows point to
nematodes and sand grains.
Scanning electron microscope image shows the upper leaf surface of Philcoxia minensis. Arrows point to nematodes and sand grains.

A worm measuring only a millimeter in length scoots its way through relatively massive grains of white sand. The worm, known as a nematode or roundworm, is seeking lunch in the form of bacteria. Suddenly, however, its journey is interrupted: it is caught on a large green surface. Unable to wiggle free the worm is slowly digested, becoming lunch itself for an innocuous purple flower called Philcoxia minensis.

As bizarre as this scenario sounds, a new paper in Proceedings of the National Academy of Sciences (PNAS) outlines the subterranean predatory behavior of a the Philcoxia minensis in the Brazilian cerrado. Employing sticky leaves that grow under the sand, the flower is able to catch tiny roundworms for sustenance in a low-nutrient environment.

Philcoxia minensis' flower.
Philcoxia minensis' flower.
In order to prove that the plant was actually ingesting the roundworms, scientists brought Philcoxia minensis into the lab and fed them roundworms containing Nitrogen-15, a stable isotope. After leaving the roundworms to their fate for two days, the researchers sampled the flower's leaves and had them tested for Nitrogen-15. The test came back positive, proving that the flower had indeed ingested the worms.

The researchers believe the plants have evolved this unique ability—the first time a carnivorous plant has been found employing stick leaves underground—in order to survive its harsh environment.

"Philcoxia minensis is found in relatively low flat areas, where water likely persists after rain. All shrubs and cacti avoid these areas, although they are common elsewhere in the immediate vicinity," the authors write, arguing that the plant is able to colonize this area due to its ability to eat roundworms.

Given the new discovery, the researchers believe it's worthwhile to explore other plant species for hidden meat-eating behaviors.

CAPTION: Caio G. Pereira, Daniela P. Almenara, Carlos E. Winter, Peter W. Fritsch, Hans Lambers, and Rafael S. Oliveira. Underground leaves of Philcoxia trap and digest nematodes. PNAS. 2012.

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Jeremy Hance
mongabay.com (January 09, 2012).

Weird carnivorous flower devours worms underground .