Pitcher Plant Symbiosis

The carnivorous plant Nepenthes rajah has developed a mutualistic relationship with mountain treeshrews.

The treeshrews perch themselves on the rim of the trap and eat the nectar produced on the lid. As it feeds, it defecates into the basin.

Pitcher plants get nutrients from digesting trapped insects, and in this case shrew droppings. This is an adaptation to the nutrient poor soils which they grow in.

Chi’en Lee on Wikipedia Commons

Nepenthes adnata is a tropical pitcher plant endemic to Sumatra where it grows on mossy sandstone cliff faces above the Tjampo River. 

Insects seeking nectar from glands below the pitcher’s rim lose their footing and fall into a pool of acid and digestive enzymes in the bottom of the pitcher. Most struggle until they drown. A few manage to swim to the sides and succeed in scaling the wall into a zone of digestive glands, only to become hopelessly mired in sticky juice.