In pitcher plants, some of the leaves have evolved into tube-shaped traps. Their smooth interior walls provide unsure footing for insects and other small animals, which easily slip and tumble down – directly into a pool of digestive fluid, where the hapless animals are dissolved and valuable nitrogen is released from their bodies. The nitrogen is then absorbed into the plant's tissue. Nitrogen is a vital nutrient for plants; among other things, it is essential as a component for the synthesis of chlorophyll.
Bat feces as a source of nitrogen
The pitcher plant Nepenthes rafflesiana, which grows in the rain forest on the island of Borneo in Southeast Asia, pursues a different nutrient-acquisition strategy: It does not rely on the carcasses of trapped animals to supplement its nitrogen intake. Instead, it uses the feces of Hardwicke's woolly bat, which consistently retires for sleep to the spacious pitchers of this plant, dropping its feces into the digestive liquid.
This relationship is of benefit to both partners: The plant offers the bat exclusive access to a safe roost and gets nutrient-rich fecal matter in return. The scientists estimate that about 34 percent of the plant's foliar nitrogen is derived from bat feces.
The pitchers of the Southeast Asian Nepenthes species are up to 25 centimeters in length with diameters ranging between four and five centimeters. The small woolly bat only has a length of three to six centimeters. Usually, the pitchers are occupied by one single animal, but sometimes mothers share a pitcher with their baby.
Extremely rare form of cooperation
"This is a very unusual example of a partnership between plants and animals," says Ulmar Grafe of the Department of Zoology III (Animal Ecology and Tropical Biology) at the University of Würzburg. So far, no other pitcher plant species has been found to get its nutrients from bat feces. There is only one other documented case to date of a partnership between a carnivorous plant and an animal: The pitcher plant Nepenthes lowii attracts tree shrews by inviting them to drink from its nectar. In order to do this, the animals sit on the pitcher, which they also use as a toilet when the occasion arises.
The exotic relationship between the woolly bat Kerivoula hardwickii and the pitcher plant Nepenthes rafflesiana has been discovered by Grafe together with the Würzburg biology students Michael and Caroline Schöner. The study also involved researchers from the University of Brunei Darussalam and the University of Greifswald.
Co-evolution of bats and pitcher plants?
At first sight, the pitcher plant does not seem to be dependent on the feces of the bats – after all, it traps insects, though not very many: "The pitchers of Nepenthes rafflesiana are pretty poor traps," Grafe explains. Compared with other carnivorous plant species, they produce very low amounts of digestive fluid and they exude hardly any insect-attracting scents.
The Würzburg researchers are going to examine such indications of a possible co-evolution between bats and pitcher plants in further detail. "Presumably, the bats first visited the pitchers – as an expedient measure, since safe roosts are limited in the rain forest," Grafe explains. Due to the feces of the animals, the plants might have been less dependent on trapping insects. This could explain the reduced production of scents and digestive liquid.
Progress of the research
Next, the biologists are going to examine how the bats are able to find appropriate pitchers to sleep in among all the plants in the dense undergrowth of the rain forest. What they would also like to know is whether there are other Nepenthes species that are specialized in recycling the feces of these small mammals.
PD Dr. Ulmar Grafe, Department of Zoology III (Animal Ecology and Tropical Biology) at the University of Würzburg, firstname.lastname@example.org
"A novel resource-service mutualism between bats and pitcher plants", Ulmar Grafe, Caroline R. Schöner, Gerald Kerth, Anissa Junaidi & Michael G. Schöner, Biology Letters, published online on 26 January 2011, doi: 10.1098/rsbl.2010.1141
Robert Emmerich | idw
Warming ponds could accelerate climate change
21.02.2017 | University of Exeter
An alternative to opioids? Compound from marine snail is potent pain reliever
21.02.2017 | University of Utah
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
21.02.2017 | Earth Sciences
21.02.2017 | Medical Engineering
21.02.2017 | Trade Fair News