Pitcher plant

The jug plant that 'eats' even mice

This plant's leaves have turned into jugs! Inside the jug is sweet liquid — an insect comes for the smell, slips off the smooth rim and can't climb out. The plant slowly 'digests' it. The biggest pitcher plant is Nepenthes rajah of Borneo: its jug holds 3 litres of water, and sometimes even a mouse falls in! Small animals use some pitchers as a 'toilet'.

Pitcher plants (Nepenthes, over 170 species) are carnivorous plants of tropical Southeast Asia, Madagascar and Australia; on nitrogen-poor soils they get nutrients from insects. The pitcher is a modified leaf tip: nectar glands, a waxy slippery wall and digestive fluid at the bottom. N. rajah (Mount Kinabalu, Borneo) is the largest: a 41 cm pitcher holding 3.5 l; rats and frogs have been found inside. Some species (N. lowii, N. rajah) have a mutualism with mountain tree shrews: the animal licks nectar from the lid and defecates into the pitcher — a nitrogen source (the 'toilet plant'). N. hemsleyana serves as a 'home' for bats, which find the pitcher by echolocation. Many species are island endemics threatened by collectors and deforestation.

Fun facts

• The biggest pitcher holds 3.5 litres of water, and rats have been found inside.
• Some pitcher plants serve as a 'toilet' for animals — that is their fertiliser.
• One pitcher plant species provides a 'home' for bats.