• January 28, 2015

The Living, Breathing World of Borneo’s Carnivorous Pitcher Plants

Tropical biologist turned photojournalist Christian Ziegler spends a lot of his time documenting the world’s rain forests and has a particular place in his heart for the leafy inhabitants of these beautiful and complex environments. Here, he shares photographs from a trip to Borneo, where he witnessed surprisingly enterprising relationships between pitcher plants and the creatures living around them.

We often don’t give plants enough credit. When observing nature, a lot of our attention is devoted to animals. Yet there is a lot to discover in the plant kingdom; in fact, they exhibit much more “behavior” then one might expect.

Nepenthes biclacarata (fanged pitcher plant) in its natural habitat: Dipterocrap swamp forest in the lowlands of Brunei.
Nepenthes bicalcarata (fanged pitcher plant) in its natural habitat: Dipterocrap swamp forest in the lowlands of Brunei.

I am fascinated by the carnivorous Asian pitcher plant, and in 2013 I spent six weeks in Borneo exploring them more. The Asian pitchers—of which there are 240 species in the genus called Nepenthes—are distant cousins to the pitchers, sun dews, and Venus fly traps found in North America. All of them grow beautifully shaped pitchers, partially filled with a digestive liquid, on the tips of their leaves. Some are tiny, the size of a thimble, while the biggest one can hold more than half a gallon.

Picture of a frog climbing into a pitcher plant
A small frog climbs up a Nepenthes tentaculata (fringed pitcher plant), probably to lay eggs in it. This and a few other frog species have evolved immunity to the digestive liquids of the pitcher so that their tadpoles can develop inside them. These represent a rare resource: pooled water, which is not commonly found along the steep slopes of the mountain.

Borneo is the center of diversity in pitcher plants, and I headed for the lowland swamp forests of Brunei, some of the last lowland forests that have not been converted to palm oil plantations. I also traveled to the mighty Mount Kinabalu, southeast Asia’s highest mountain at 13,435 feet and home to some 25 species of pitcher plants, some of them endemic to the mountain.

My trip was inspired by recent research suggesting that many pitcher plants have very specific “diets.” Carnivory in plants has evolved several times in independent places—always in very nutrient poor habitats—as a way for the plant to gain additional nutrients. Until recently, all pitchers were thought to capture insects, but as is often the case, the reality is more complicated. In fact, scientists have discovered a number of unexpected ways that pitcher plants survive, often involving mutualism with animals.

A side view inside the endangered Nepenthes rajah pitcher reveals mosquito larvae specially adapted to the digestive enzymes of the plant. The largest pitcher of the genus, Nepenthes rajah holds up to three liters of content.

My first surprise in the swampy, steamy forest of Brunei was a vegetarian carnivorous plant. It turned out that the digestive enzymes in that pitcher are best suited to break down plant matter, not animal. One recently discovered species “collaborates” with a tiny bat, which uses the elegant, long pitchers as a place to sleep in the daytime. The bats feces and urine provide the plant with sought after nutrients.

Picture of an ant coming out of a pitcher plant
Nepenthes bicalcarata (fanged pitcher plant) and the carpenter ant Camponotes schmitzi have a mutualistic relationship: While the plant provides a home for the small ant colony of up to 30 individuals in the stem of its pitcher, the ants keep the chemistry of the pitcher’s liquid balanced by removing large insects which have found their way inside. If the insects were to rot in the liquid, it would spoil.
Picture of an ant colony inside the stem of a pitcher plant
A cut-open stem reveals the ant colony within.

In that same forest one can find a species of pitcher plant that houses its own cleaning crew: A small colony of ants resistant to its digestive juices lives in its hollow stem. In fact, the ants can swim and dive in the liquid without drowning, and make a chore of dragging large dead insects out of the pitcher, which would otherwise spoil the digestive process.

Picture of a tree shrew licking nectar off of a pitcher plant
Nepenthes rajah has a mutualistic relationship with the tree shrew Tupaia montana and some nocturnal rats. The plant offers nectar inside its lid, which is frequently licked off by the tree shrews in the daytime. While licking, the shrew often sits over the opening of the pitcher, defecating or urinating. This is the plant’s source of phosphorus and nitrogen.

Climbing Mount Kinabalu, hiking through different forest zones, I get to see a great variety of pitcher shapes and sizes and pitchers being used as a safe place for the eggs of snails and certain frogs. I spend the last week of my trip photographing the largest known pitcher plant—Rajah’s pitcher (N. rajah) and its close relationship with a mountain tree shrew. Rajah’s pitcher lays on its side, its large lid with nectar glands sticking up. When the shrews visit to lick the nectar, its feces end up in the pitcher, providing nourishment for the plant.

I leave Borneo impressed and awed by just how much behavior these pitcher plants display and amazed at how much more there is to explore and discover in the vegetable kingdom.

For more animal-plant interactions, check out Ziegler’s piece on the Ochroma tree of Panama. You can also follow Ziegler on his website.

There are 31 Comments. Add Yours.

  1. Sternblume
    March 15, 2016

    Simply stunning and inspiring. I have been lucky to see Nepenthes in their habitat, but I was surprised to read about their symbiotic relationship with the swimming ants – what a find! <3

  2. Mahendra Jaiswal
    March 10, 2015

    Excellent. Keep up the good work.

  3. Armando Lanzini
    March 10, 2015

    Fantastic! Fascinating! And worrying… Anyway; top quality, worthy of National Geographic

  4. Armando Lanzini
    March 10, 2015

    Fantastic; fascinating! Article and photographs. Worth of National Geographic!

  5. Anne
    March 10, 2015

    Human over population is single thing that is contributing to extinctions, loss of habitat and global warming for that matter. But humans just can’t stand anybody even suggesting this truth. Since the 60’s human population has doubled! Not one single politician will touch this terrifying situation with a ten foot pole!

  6. Lori Hubley
    March 10, 2015

    Amazing and incredible! Do we need any MORE reason to stop palm oil production plantations? Threatening extinction of not only animals but rare plant species as well.

  7. Bi Veronica
    March 10, 2015

    Interesting and beautiful work, something most people will overlook as they pass by. Symbiosis is a natural phenomenon in life, be it in higher or lower lives, but it becomes so significant or remarkable and interesting when some one brings out the details the way you have done. BRAVO!!!

  8. Eric Bauwens
    March 10, 2015

    Superb. Amazing. Let us hope these forests will be saved from logging and human destruction !

  9. arcesio
    March 9, 2015

    Excelente que buen estudio

  10. Niyazi
    March 8, 2015

    Words fail… Just amazing..

  11. Niyazi
    March 8, 2015

    my words fail.. amazing work!

  12. Niyazi
    March 8, 2015

    respect to amazing work

  13. Krishna
    February 21, 2015

    I always buy three buhcnes and split them between two vases, usually one colour, yellow in spring, white summer and winter, orange in autumn, and deep pink peonies in May. That way they go with my seasonal colour schemes.I do love fresh flowers:-). Yours are lovely.

  14. Mimi Jones
    February 18, 2015

    My vocabulary lacks enough adjectives to honor your work, and other research photographers in the findings you bring to the world via your photo proofs and the in-depth research about what your pictures shows. It’s unfortunate that so many areas have been destroyed for plantation crops of one plant when the complexities of all life forms rely on that jungle of diversity to thrive on, while the jungle relies on the diverse life forms for its nourishment and growth! I am but one of the many millions that are in awe of Mother Nature. Many thanks for your efforts to show the world what we’ll be missing in the future, once it arrives and the diversity is gone from our lives.

  15. Satyabrata Majumder
    February 9, 2015


  16. Satyabrata Majumder
    February 9, 2015

    Amazing Work. Want to know more about this unknown world.

  17. Joachim Sapuli
    February 6, 2015

    I have surprisingly interested to your work,hoping to know more

  18. Sigi
    February 3, 2015

    Awesome pictures and specific information about the symbiosis if nepenthes and animals!

  19. Bruno
    February 2, 2015

    Way to go, Christian! Amazing work, as usual…

  20. Mitchell Hetrick
    February 2, 2015


    February 2, 2015

    amazing………and good job sir

  22. Michael
    January 31, 2015

    Great article except for consistent misspelling of N. bicalcarata

    • Alexa Keefe
      February 2, 2015

      Thank you for your keen eyes. We have updated the spelling.

  23. Haren carpenter
    January 30, 2015

    Thank you for the splendid info rmation

  24. Hunter Trahan
    January 29, 2015

    It’s beautiful how drastically different life forms can evolve to do the same thing from different places.

  25. Antonia Gavina
    January 29, 2015

    Nature is very beautiful. I love the pictures.

  26. Yolanda Patterson
    January 29, 2015

    Have always had a fascination with these plants and thank you for bringing me into their world, a little closer!

  27. Allister jane lynrah
    January 29, 2015

    fascinating read,we have the same in northeast india,but they are without fangs.

  28. Bonita Nevins
    January 29, 2015

    Most interesting thing I’ve ever heard of – who knew?!

  29. rajma
    January 29, 2015

    Beautiful feature. Shows how much more there is still unexplored and unknown to us.

  30. Jim Denton
    January 28, 2015

    Simply wonderful photos– stunning ! getting to see what you saw is so great for all of us that will never get there in person! Please, Sir may we have more ?

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