Nepenthes carnivorous plants look like toilets, trapping insects and other small creatures in a bowl-shaped pitcher with an overhanging lid. But some species of nepenthes growing on mountains in Borneo have given up carnivory and instead encourage animals to poo in their pitchers.
This toilet habit was discovered when mountain tree shrews were found sitting on the enormous pitchers of nepenthes lowii, and as the shrews licked fatty food oozing from the lid of the pitcher they plopped their droppings inside. It was later found that rats, bats and a bird also made use of the plant toilets.
Other nepenthes species were also found collecting animal droppings, such as Nepenthes hemsleyana, which even advertises itself to a particular species of bat using the shape of its pitchers to reflect the animal’s ultrasound calls. The pitchers provide a special ridge for the bat to cling on to while it relieves itself.
All these plants grow on mountain peaks where insects are scarce, making carnivory very difficult. But the poo habit was found to be so nutritious it gave these pitcher plants more than twice the nitrogen of prey caught by carnivorous nepenthes plants.
