Pitcher plants are dioecious, meaning that male and female flowers grow on separate plants (4), and only begin to flower once the upper pitchers are produced (5). The flowers produce large amounts of nectar during the early evening and night, which evaporates by morning. This nectar attracts flies during the early evening and moths at night to aid pollination. Once fertilised, a fruit usually takes about three months to develop and ripen. The fruits of Nepenthes species produce between 100 and 500 very light, winged seeds, which can measure up to 30 millimetres long, and are thought to be dispersed by the wind (2) (6). Despite enormous numbers of seeds being produced, only a few manage to germinate and only a fraction of those survive to maturity (2).
Carnivorous pitcher plants are adapted to grow in soils low in nutrients. Although the plants do gain some nutrition through the soil, and energy through photosynthesis, they supplement this with a diet of invertebrates, usually consisting of ants, cockroaches, centipedes, flies and beetles (4). Insects are attracted to the pitchers by their bright colours and nectar, which is secreted by glands situated on the lid of the pitcher. The insects fall into the acidic fluid at the base of the pitcher and, unable to escape, they drown. The acidic fluid in Nepenthes inermis is extremely viscous suggesting that this species traps a large number of flies compared with other Sumatran pitcher plants (4). Digestive enzymes are then released to break down the captured prey (4).
Despite the hostile environment of the pitchers, they can be home to number of animals. The red crab spider (Misumenops nepenthicola) inhabits pitcher plants in Malaysia, Indonesia and Singapore. This spider ambushes insects that crawl into the pitcher and preys upon other insects, such as mosquitoes, as they emerge from larvae that live in the pitcher fluid (2).