Pitcher plant  (Nepenthes villosa)

Classified as Vulnerable (VU) on the IUCN Red List 2006 (1) and listed on Appendix II of CITES (2).

Nepenthes villosa is a spectacular species of tropical pitcher plant (Nepenthes) (3), a group of carnivorous plants equipped with large, modified, pitcher-shaped leaves that trap and digest small organisms (4). These deadly traps hang from coiled tendrils, and are filled with acidic digestive juices. In order to prevent the digestive liquid from being diluted by rainwater, the pitchers are covered by small lids as they grow, which open up when the pitchers are fully developed (4). The pitchers of N. villosa range from green to deep orange or rich maroon (5). The most notable feature, however, is undoubtedly the pitchers’ heavily ribbed, or ‘toothed’, peristome (lip or brim at opening) (5) (6), which is smooth in most other Nepenthes species.

Known only from Mount Kinabalu in Borneo (1).

Grows in mossy forest, or among boulders, shrubs and grass in open conditions (1), between 2,400 and 3,200 m above sea level (5). Reaching the summit of Mount Kinabalu, this is one of the highest growing of all tropical pitcher plants, and is frequently bathed in clouds of mist for most of the day (5).

Nepenthes pitcher plants have evolved carnivorous habits as the answer to growing in extremely nutrient-poor habitats (7) (4). The plants are able to break down and absorb nitrogen and other nutrients from animals, usually invertebrates such as insects, that fall into the pitchers. This supplements any nutrition gained from the soils and therefore allows these plants to survive where others may not. Nepenthes plants attract their prey with nectar, aromas and visual signals such as colour (4). The brim of the pitcher, the peristome, produces the highest amount of nectar, and animals stepping on the slippery, waxy surface of the peristome often fall in. There, unable to escape, they drown in the pitcher fluid and their bodies are broken down by digestive enzymes (7).

Nepenthes are dioecious, meaning that there are separate male and female plants. Likely pollinators include flies, moths, beetles, bugs and ants, which have all been observed visiting the flowers. The fruit takes around three months to develop, and can contain 500 or more seeds, which are very light and have long wings, and are carried by the wind to aid dispersal (7).

The main threat to tropical pitcher plants (Nepenthes) is habitat destruction. However, as popular ornamental plants, they are also widely collected from the wild, and due to their low population numbers, commercial collection and illegal trade has had a serious impact (4).

All Nepenthes species are listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which restricts the legal trade of these plants. Methods have also been developed to produce tropical pitcher plants from tissue culture, and the horticulture and cultivation of plants produced by this process may significantly help reduce the impact on wild populations (4). Furthermore, most, if not all, of the N. villosa populations occur within the Kinabalu National Park (1).