Resident bats use pitcher plant as toilet

Jan 27, 2011 by Lin Edwards report
Nepenthes rafflesiana. Photo: Wikipedia.

(PhysOrg.com) -- The pitcher plants are carnivorous species that usually feed on insects and small vertebrates, but one species has been found that prefers to dine on the feces of bats.

Scientists from the University Brunei Darussalam and from Germany have been studying the aerial pitcher plant Nepenthes rafflesiana variety elongata, from . The plants live in peat bogs and heaths and are notable for their extremely large aerial pitchers.

Pitcher plants grow on nutrient-poor soils and supplement their nitrogen source by feeding on and small animals. The victims are attracted to the pitcher by its colors and smells, but once inside they are trapped on the slippery sides and are drawn into the fluid at the bottom where they drown. The fluid contains to extract nitrogen and other needed nutrients as the bodies are digested.

N. r. elongata differs from other pitchers in having a much larger (around 4 x) pitcher than related species, but it traps only around one seventh of the insects consumed by other pitcher species. The researchers found Elongata had low volumes of digestive fluids and enzymes and low amounts of the insect-attracting volatile compounds usually found in pitchers, which makes them less attractive to insects.

Instead of insects in the large pitchers, the researchers, led by tropical ecologist Dr. Ulmar Grafe, sometimes found roosting . Dr. Grafe spent a year inspecting 400 Elongata plants and found 32 bats in that time, among them a whole family of offspring and young nestled in a single pitcher. Some of the tiny (4 g) bats, all Hardwicke’s woolly bats (Kerivoula hardwickii hardwickii), were fitted with radio-trackers, and the results of tracking indicated they roosted only in the pitchers.

The Elongata pitchers are perfectly suited to their residents, with a girdle half-way up to ensure they do not slip down the sides, and there is little fluid and so no chance of being drowned if they did slip.

The researchers found that about 33.8 percent of the foliar nitrogen in the originated in the feces of the bats, and the level of nitrogen was much higher than in pitchers of the same species that did not have a resident bat.

The association between the pitcher and bat is only the second case of a mutualistic association between a pitcher plant and a mammal (the other being a tree shrew), and is the first case of a pitcher that attracts bats to roost in its aerial pitchers and use their droppings as a source of food.

The bat also benefits from the association because it is sheltered and hidden from predators when it is nestled within the pitcher. Dr. Grafe said the environment within the pitcher is also free of the parasites that often live in bat roosts.

The paper is available online at the Biology Letters journal.

Explore further: Male monkey filmed caring for dying mate (w/ Video)

More information: A novel resource–service mutualism between bats and pitcher plants, Biol. Lett. Published online before print January 26, 2011, doi:10.1098/rsbl.2010.1141

Related Stories

Anti-adhesive layers leave no hope for insects

Jan 13, 2006

Plants are able, using organic substances, to achieve effects that we otherwise mostly know only from technical materials. One example of this is the carnivorous pitcher plant, as researchers from the Max Planck ...

Some bat numbers up in Britain

Dec 31, 2006

At least four species of bats in Britain have reversed decades of declining populations and have grown in numbers recently.

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

Apr 18, 2014

(Phys.org) —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

hush1
not rated yet Jan 27, 2011
lol Obviously, the working hypothesis was mutualistic association. This appears to be rare. A focus only on pitcher plants and mammals can render the scarcity of mutualistic association to be a deception. And only a broader study and scope of plant and animal life can limit the uncertainty of how rare mutualistic association is, in Nature.

And why is this funny? To find the descriptor "toilet" in association with plants and animals in the wild is as rare as the authors' assertion that mutualistic association is not widespread.

Is there a better descriptor? No. Just sounds funny.

More news stories

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Poll: Big Bang a big question for most Americans

Few Americans question that smoking causes cancer. But they have more skepticism than confidence in global warming, the age of the Earth and evolution and have the most trouble believing a Big Bang created the universe 13.8 ...

Making graphene in your kitchen

Graphene has been touted as a wonder material—the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.