Pitcher-plants: Nature's toilet bowl.

Pitcher plants are carnivorous plants, that unlike active traps such as the Venus Fly Trap, passively gain nutrients from animal sources. In general, the pitchers produce nectar that attract insects and other small animals (I have found frogs and salamanders in Sarracenia purpurea leaves), which then fall into the pitchers, drown, and decompose. The plant is then able to absorb nutrients from this decomposing material. Generally decomposition within the pitchers is aided by an inquiline community of microbes, rotifers, copepods and a variety of other invertebrates.

Pitcher plants usually grow in nutrient poor environments (acid bogs, tropical mountain tops etc..) and the carnivory is assumed to be an adaptation to such environments, allowing the plants to obtain the nitrogen and phosphorous necessary for growth.

The genus Nepenthes has gained attention over the last year with the recent discovery of one of the largest pitcher plants, Nepenthes attenboroughii, that can have 1.5-2 liters of water within their pitchers. A recent paper in Biology Letters (see cover image) describes another novelty within the pitcher plants. Nepenthes lowii has two types of pitchers: young plants produce ground-level pitchers which are well-suited to insect capture, whereas larger, more mature plants produce aerial pitchers which are not well-suited to insect capture, and various hypothesis have been put forth as to what these aerial pitchers were doing. In their recent paper, Clarke and colleagues show via isotope analysis that the majority of Nitrogen in the aerial pitchers was coming from the faecal matter the mountain tree shrew, Tupaia montana.

The aerial pitchers are have wide, non-slippery mouths and a large hood that folds away from the pitcher. The nectar is produced on the hood, and in order for the mountain shrew to gain access to the nectar, it much perch itself on the pitcher with its 'rump over the pot' if you will. It seems that this placement of the shrew on the pitcher is prime placement for the pitcher to collect faeces that are dropped by the shrew while it eats its dinner.

Here is an example of a plant that collects its own manure fertilizer. What a great system.


Clarke, C., Bauer, U., Lee, C., Tuen, A., Rembold, K., & Moran, J. (2009). Tree shrew lavatories: a novel nitrogen sequestration strategy in a tropical pitcher plant Biology Letters, 5 (5), 632-635 DOI: 10.1098/rsbl.2009.0311