Pitcher Plants
Have you ever heard of a plant that could eat birds and mice? Well now you have! Pitcher plants come in various forms and can seem quite sinister. The actual 'pitcher' is a modified cup-shaped leaf with a protruding rim called a peristome which is usually smooth, ribbed and very slippery when wet. After being tempted by sweet nectar and the bright colour of a pitcher, an unsuspecting creature may slip into the pit. Resistance is useless as the animal struggles to climb back up with smooth sides and drowns in a solution of rainwater and acidic digestive juices. Glands in the plant then absorb the dissolved nutrients.[1][2]
The highest diversity of pitcher plants is in southeast Asia where they are particularly concentrated on the islands of Sumatra and Borneo. The largest of the species are from the Nepenthes genus. Surprisingly, in 2011, a blue tit was found to have been eaten by a large pitcher in a tropical garden in Somerset.[3] These larger species more often feed on lizards and mice.[2]
The pitcher featured in this photograph is called Nepenthes Rajah. Interestingly it has a mutualistic relationship with brown rats and mountain treeshrews. Whilst feeding on a carbohydrate rich solution on the rim lid of a pitcher, these small mammals defecate into the pitcher and provide it with nutrients.[4] This perfect timing of defecation is due to the fact that the solution the mammals drink from the pitcher contains a laxative.[5] Other pitcher plants would rather digest leaf litter![6]
Pitcher plants are often called 'Monkey Cups' as monkeys have been seen drinking the water that collects inside them.[2]
Photograph: "Rattus baluensis visiting a Nepenthes rajah pitcher at night." Photo taken by Ch'ien Lee, obtained via Wikimedia Commons.
[1] Krol, E.; Plancho, B.J.; Adamec, L.; Stolarz, M.; Dziubinska, H.; Trebacz, K, (2011), Quite a few reasons for calling carnivores 'the most wonderful plants in the world, Annals of Botany 109 (1): 47–64. doi:10.1093/aob/mcr249.
[2] BBC Nature, (2014), Nepenthes, [online], Available at: http://www.bbc.co.uk/nature/life/Nepenthes [Accessed 5 January 2014].
[3] Daily Mail, (2011), Garden bird eaten by carnivorous plant, [online], Available at: http://www.dailymail.co.uk/news/article-2022253/Garden-bird-eaten-carnivorous-PLANT--Somerset-wasnt-swallow.html [Accessed 5 January 2014]
[4] Greenwood, M; Clarke, C; Lee, C, C; Gunsalam, A; Clarke, R, H, (2011), A Unique Resource Mutualism between the Giant Bornean Pitcher Plant, Nepenthes rajah, and Members of a Small Mammal Community, PLoS ONE 6(6): e21114. doi:10.1371/journal.pone.0021114
[5] BBC, (2014), Hidden Kingdoms series: Secret Forests (episode 2), first broadcast BBC One, 8:00PM Thu, 23 Jan 2014.
[6] Encyclopeadia of Life/ EOL, (2014), Nepenthes: Tropical Pitcher Plants, [online] Available at: http://eol.org/pages/60885/details [Accessed 5 January 2014]
