Pitcher plant  (Nepenthes lowii)

Nepenthes lowii is one of the most unusual pitcher plants of the Nepenthes genus (4), a group of spectacular carnivorous plants equipped with large, modified, pitcher-shaped leaves that trap and digest small organisms (5). The upper pitchers of N. lowii are dark green on the outside, dark purple-red on the inside, and are known for their markedly narrowed ‘waist' in the middle and huge, flaring mouth (4). It is thought that the exaggerated narrowing of the ‘waist' may help prevent rainwater from diluting the acidic digestive juices that exist in the bowl of the pitcher (6). The lids, which cover the pitchers as they grow but open when the pitchers are fully developed (5), are covered with coarse bristles on their underside (4). A white, sugary, nectar-like substance is secreted amongst these bristles, which is thought to attract certain types of birds and shrews, whose excrement forms an unusual foodstuff for this plant (4).

Endemic to Borneo (1).

Grows in mossy forest along ridge tops between 1,600 and 2,600 m above sea level (1).

Nepenthes pitcher plants have evolved carnivorous habits as the answer to growing in extremely nutrient-poor habitats (2) (5). 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 (5). 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 (2). Unlike other pitcher plants, however, recent studies have shown that N. lowii has also adapted to feeding on animal droppings, especially those of birds and tree shrews (4). These plants produce a huge amount of nectar on the underside of the pitcher lid, and the edge of the pitcher is an ideal place for birds and shrews to perch while feeding on the nectar. The wide pitcher opening then collects the animals' excrements, thus feeding the plants (2) (4).

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 (2).

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 (5).

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 (5). Furthermore, most, if not all, of the N. lowii populations occur within protected areas (1).

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk