Tuesday, November 08, 2011

Small mammals use Borneo pitcher plant as toilet in exchange for nectar

Tree shrews and nocturnal rats in the forests of Borneo have a unique relationship with carnivorous pitcher plants. The mammals defecate, and the pitchers are happy to receive.

A study published on May 31 in the Journal of Tropical Ecology shows a species of giant mountain pitcher plants (Nepenthes rajah) supplements its diet with nitrogen from the feces of tree shrews (Tupaia montana) that forage in daylight and summit rats (Rattus baluensis) active at night. When the small mammals lick nectar from the underside of the pitcher’s lid, they stand directly over the jug-shaped pitcher organ.

The pitchers grow in nutrient-poor, acidic soils and require a supplemental source of nitrogen. Carnivorous plants usually digest bugs, grabbing nitrogen from protein. The Bornean pitchers consume nitrogen-rich feces.

Researchers have already documented tree shrews using two species of Nepenthes pitcher plants as toilets. A third species provides daytime roosts for Hardwicke’s woolly bats in exchange for guano.

However, this is the first instance of a carnivorous plant interacting with two different mammal species, and the first attempt to measure how the plants attract the dining and defecating animals.

“The fact that one of the mammals visits the pitchers during the day and the other one visits during the night indicates that this plant is involved in one of these mutualistic interactions around the clock, which is quite interesting,” said Charles Clarke, an ecologist at Monash University, Malaysia campus, who published a similar study at the same time, in an interview with mongabay.com.

Continue reading (Incl. Pics) at: Small mammals use Borneo pitcher plant as toilet in exchange for nectar

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