The symbiosis between Nepenthes and bats

We often hear about the symbiotic relationships between certain animals and carnivorous plants – a phenomenon that is all the more astonishing given how thin the line is between predator and prey! Studies on this subject are ongoing, and the discoveries are sometimes quite unusual.

Dr Ulmar Grafe and his scientific team have demonstrated that a variety of Nepenthes in Borneo benefits from bat droppings, which make the famous pitcher traps the perfect resting place. Nepenthes rafflesiana var. elongata, as it is known, thrives in very poor soil, as is typical of carnivorous plants. The problem is that its traps catch far fewer insects than other Nepenthes species. To survive, its close relationship with bats is therefore essential: the droppings, digested at the bottom of the pitchers, provide all the nitrogen it needs! For its part, the famous nocturnal mammal does not do this by chance. Blood-sucking parasites thrive in its droppings; the Nepenthes’ pitchers thus act as veritable clean toilets!

Such mutualism between a carnivorous plant and a mammal is unprecedented. These discoveries are fascinating, but they also serve as a reminder of the consequences that the extinction of a single species could have for an entire biotope…