Nepenthes or Old World Pitcher Plants grow in places with poor nutrition in the Asian tropics. The Nepenthaceae consists of a single genus containing more than a hundred species. Nepenthes pitchers develop at the end of tendrils extending from leaves as illustrated in botanical drawings and photographs. Pitchers range in size from a couple of centimetres to pitchers half a metre tall producing up to two litres of digestive soup. Some are climbers, some are ground dwelling and others live in trees.
How do pitcher traps catch prey?
Pitcher traps are modified leaves that act as pitfall traps, capturing insects and other small prey such as insects and ants. There have even been reports of small rodents and birds being found in these traps. Prey attracted to the leaf by sweet nectar, is guided towards the mouth of the trap by two ladder like wings. The peristome at the entrance of the mouth is slippery and gravity helps prey fall into the trap. The pitcher is divided into two distinct domains, the upper part of the trap is coated in a waxy surface so it is difficult for prey to hang on and climb out again. The leaf has secretory glands which exude digestive enzymes into the pool filling the bottom of the leaf. Once trapped the creature is digested and its nutrients absorbed by the plant.
Nepenthes often interact with communities of bacteria, fungi or larger animals living in the pitchers to the benefit of both the plant and community. Nepenthes lowii from Mount Kinabalu in Borneo provides nectar to attract small mammals, and a cup-shaped toilet to collect their faeces. Compounds found in the digestive soup of Nepenthes leaves may be medicinally useful. Anti-fungal agents found in the digestive juices of Nepenthes khasiana are being developed as broadly effective fungicides to treat human fungal conditions.