The evolution of carnivorous pitcher plants

The pitcher plant trap is a striking example of convergent evolution. Unrelated lineages of pitcher plants (especially the families Nepenthaceae, Sarraceniaceae and Cephalotaceae) have independently evolved remarkably similar traps as adaptations to survival in nutrient-poor environments. Our work highlights that within groups of related pitcher plants, species also show intriguing patterns of divergent evolution. 

Divergent evolution in Nepenthes pitcher plants is linked to novel strategies for obtaining nutrients from specific sources, such as insects, leaf litter and even mammalian faeces. The bizarre assortment of shapes and sizes of pitcher trap in Nepenthes adapted to specific nutrient sources are analogous to the well-known examples of adaptive radiation seen in animals, such as the beak shapes of Darwin’s finches. We are interested in the extent that adaptive radiation has shaped the diversity of pitcher plants. 

Oxford Botanic Garden has an extensive research collection of carnivorous Nepenthes pitcher plants grown under glass. Our work also explores the functionality of the slippery surface of the Nepenthes pitcher, and potential technological applications.

 

tree shrew

A tree shrew feeding from a pitcher of Nepenthes lowii, providing the plant with nutrient-rich faeces. Photo by Ulrike Bauer, sourced from Thorogood et al., 2017 https://doi.org/10.1111/nph.14879

Nepenthes rajah carnivorous pitcher plant

Nepenthes rajah growing on Mount Kinabalu, Borneo.

evolution of carnivorous pitcher plants

A bat visiting the pitcher of Nepenthes hemsleyana. Roosting bats provide the plant with nutrient-rich faeces.

Selected References:

Thorogood C, Bauer U. 2020. Shedding light on photosynthesis in carnivorous plants. A commentary on: ‘Nepenthes × ventrata photosynthesis under different nutrient applications’ Annals of Botany 126(1):iv-v.
Box F, Thorogood C, Hui Guan J, 2019. Guided droplet transport on synthetic slippery surfaces inspired by a pitcher plant. Journal of the Royal Society, Interface 16(158):20190323.
Thorogood CJ, Bauer U, Hiscock SJ (2017). Convergent and divergent evolution in carnivorous pitcher plant traps. New Phytologist 217:1035-1041.