Relationship Provides Nutrients

a large dark purple plant shaped like a pitcher sits on the ground, open for prey

Biological Strategy

Mountain treeshrew

AskNature Team

Image: Andrea Schieber / Flickr / CC BY - Creative Commons Attribution alone

Cooperate/Compete Between Different Species

From parasitism to mutualisms, there are endless interactions between organisms in nature. Interactions between species that lead to a negative outcome for one species are known as competition. Cooperation occurs when organisms work together for the benefit of each organism or species. While competition often occurs over resources or mates, the more biologists have begun to look for examples of cooperation in nature, the more they have found. For example, around 90% of plants have a beneficial partnership with fungi. Fungi provide the plant with nutrients such as nitrogen and phosphorus, in exchange for sugars from the plant.

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Capture, Absorb, or Filter Chemical Entities

Living systems often require chemical elements and chemical compounds, including complex sugars, proteins, and odor-making compounds, to perform critical activities. These compounds exist in various states–solid, liquid, and gas–and are ubiquitous in soil, water, and air. This requires that living systems not only have ways to capture, absorb, or filter them, but also ways to differentiate among them, selecting those that are valuable or harmful. For example, mangrove trees live with their roots in salty water and sediments. Various mangrove species have different strategies for removing salt from the water they take in so that their tissues can use the fresh water.

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Mammals

Class Mammalia (“breast”): Bats, cats, whales, horses, humans

Mammals make up less than 1% of all animals on earth, but they include some of the most well-known species. We know first-hand some of the characteristics that make mammals unique, like having hair, being able to sweat, and producing milk through mammary glands. Another critical shared feature is a set of highly-specialized teeth. Unlike sharks or alligators, for example, whose teeth are generally all the same size and shape, mammals have differently shaped teeth in different areas of the jaws to target specific foods or foraging strategies.

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Nepenthes pitcher plants and treeshrews maintain a mutually beneficial relationship by exchanging nutrients.

In Borneo’s tropical forests, a large, carnivorous pitcher plant, Nepenthes rajah, and a small mammal called a treeshrew have a great relationship. The pitcher plant lures the treeshrew in for some delicious nectar. While there, the mammal marks its feeding spot by dropping nitrogen-rich feces into the pitcher.

Pitcher plants have special leaves that form a tall jug, called a pitcher. They are best known for luring insects, especially ants, to the rounded rims of their pitchers. The rim of the pitcher has a slippery surface that causes insects to lose their grip and fall inside. Juices then digest the insects to release nutrients. However, Nepenthes rajah lives in a nutrient-poor area in the mountains that doesn’t have a lot of insects. So attracting, but not eating, the treeshrew is a good solution for getting additional nitrogen. At the same time, the treeshrew also gets fed. Nitrogen is important for and it helps the plant build leaves, roots, and stems.

Nepenthes rajah doesn’t have slippery surfaces because it’s not going to eat the treeshrew. Instead it has a special trick to get treeshrews do what the plant needs. Over the top of the pitcher is a lid, kind of like a toilet bowl lid (watch video). The lid angles upward over the top of the pitcher, and the nectar is on the edge of the lid. The distance from the nectar to the front of the pitcher’s opening is the exact same length as the treeshrew. This forces the animal to straddle the rim as it licks the nectar off the lid, and its feces drop directly into the pitcher.

This plant-mammal story can teach us the importance of meeting our own needs while also helping other people. Because it’s good for both parties, the relationship is likely to continue.

Image: Chien C. Lee / CC BY - Creative Commons Attribution alone

Mountain treeshrew visiting Nepenthes lowii pitcher plant

Last Updated June 18, 2020

References

“The carnivorous pitcher plant genus Nepenthes grows in nutrient-deficient substrates and produce jug-shaped leaf organs (pitchers) that trap arthropods as a source of N [nitrogen] and P [phosphorus]. A number of Bornean Nepenthes demonstrate novel nutrient acquisition strategies. Notably, three giant montane species are engaged in a mutualistic association with the mountain treeshrew, Tupaia montana, in which the treeshrew defecates into the pitchers while visiting them to feed on nectar secretions on the pitchers’ lids…During initial observations we discovered that the summit rat, R[attus]. baluensis, also feeds on sugary exudates of N. rajah pitchers and defecates into them, and that this behavior appears to be habitual. We found that both T. montana and R. baluensis are engaged in a mutualistic interaction with N. rajah…This study is the first to demonstrate that a mutualism exists between a carnivorous plant species and multiple members of a small mammal community. Further, the newly discovered mutualism between R. baluensis and N. rajah represents only the second ever example of a multidirectional resource-based mutualism between a mammal and a carnivorous plant.” (Greenwood et al. 2011: 1)

Journal article