During a several-day trip with Indonesian colleagues to the Indonesian province of North Kalimantan, on the island of Borneo, botanist Martin Dančák of Czech’s Palacký University noted plants which were undoubtedly Nepenthes but produced no pitchers.
After a careful search, they found a couple of aerial pitchers, which led them to discover a strategy so far unknown from any other species of carnivorous plant: catching the prey in the soil.
The Nepenthes plant is widely spotted in southern China, Indonesia, Malaysia, Philippines, Australia, India, and Siri Lanka.
It has modified leaves known as pitfall traps or pitchers, whose inner walls are covered with a waxy substance and hairs or folds that lock the prey insects in. The pitchers also contain glands that secrete a liquid that fills a part of it.
One of its sides produces a nectar that attracts insects and traps them after they fall in. The prey is then consumed using digestive enzymes, and the plant uses the resulting nutrients to grow.
While most of these plants’ pitchers are found above the ground, Dančák and his colleagues discovered that this species places its up-to-11-cm-long pitchers underground, where they are formed in cavities or directly in the soil and trap animals living underground, usually ants, mites and beetles.
The findings were announced in the journal PhytoKeys on June 29.
The newly discovered species grows on relatively dry ridge tops at an elevation of 1,100-1,300 m. According to its discoverers, this might be why it evolved to move its traps underground.
"We hypothesize that underground cavities have more stable environmental conditions, including humidity, and there is presumably also more potential prey during dry periods," adds Michal Golos of the University of Bristol, United Kingdom, who also worked on this curious plant.