Plants that feed on animals underground discovered

09.07.2012 09:22

The Telegraph: Three species of carnivorous plant that feed on worms underground have been discovered in the Brazilian savannah.

It could require a re-imagining of The Day of the Triffids – scientists have discovered a new type of carnivorous plant that traps and devours its prey underground.
Botanists have found three plants, all relatives of the popular snapdragon garden flowers, that have an unusual network of sticky leaves underground.
These leaves allow the plants to trap and digest worms, and possibly other creatures, that stray onto their sticky surfaces in the soil.
While there are many species of carnivorous plants that use insects, frogs and even small mammals to supplement the nutrients they need to grow, none have ever been found to trap their prey beneath the ground.
Botanists now believe there could be many other plants that use this previously unrecognised method of killing and consuming animals.
Most common carnivorous plants use leaves above the ground to trap their prey. Pitcher plants fold their leaves into containers that hold a digestive soup which insects fall into, while the Venus Fly trap snaps its leaves shut on prey that walk onto them.
Dr Peter Fritsch, from the California Academy of Sciences who led the research, has begun searching for related plants that may also digest animals underground and said there could even be well known plants that employ this approach to become carnivorous.
He said: “The first time I saw these plants I couldn’t believe what I was seeing. I have never seen anything like them before. The soil they grow in is very poor and sandy. Their roots basically just provide support but they have leaves that grow underground too.
“We took a closer look and found there were the remains of worms stuck to the upper surfaces of the leaves underground.
“There could be many more plants like this that haven’t been recognised yet. There are many well known plants that have been suggested to be carnivorous because they fit the profile but no one has worked out whether they are or not. Some could use adaptations similar to this.”
The plants, called Philcoxia minensis, Philcoxia goiasensis and Philcoxia bahiensis, are all found in the Brazilian high savannah. They are extremely rare and were first described by Kew botanist Peter Taylor.
He suggested that because the plants grew in nutrient-poor patches of white and lacked the usual mineral-absorbing network of fine roots, the plants could be carnivorous.
He also noticed the upper surface of its leaves are dotted with glands that secrete a sticky substance.
But it wasn’t until Dr Fritsch and his colleagues examined the plants in more detail that they found tiny round leaves barely an eighth of an inch across under the surface of the soil were littered with the remains of nematode worms.
Working with researchers from the State University of Campinas in Sao Paulo, the scientists then “fed” worms that had been doped with nitrogen isotopes to the plants. They found that within 24 hours some of the nitrogen had passed from the worms to the plants.
They also discovered powerful enzymes on the surface of the leaves that help digest the bodies.
Dr Fritsch believes the plants may trap other animals aside from worms including passing insects, but has not found any yet as their bodies may have digested away too quickly for the researchers to spot.
“It is not clear yet if the plants attract organisms into their sticky leaves as we haven’t found anything to suggest that,” he said. “It could be a passive system where the animals come into contact with the leaves as they pass by and become trapped.
“We are now starting to do some genetic population work to find other related species.”
By Richard Gray