Scientists observed a curious relationship between pitcher plants and bats in Borneo. The plants provide the bats with a cool and safe place to roost, while the bats fertilize the plants with their droppings.
An even more intriguing observation revealed the plants boast special structures that allow them to reflect bats' ultrasonic call back to them to make it easier for the animals to find them, Cell Press reported.
"With these structures, the plants are able to acoustically stand out from their environments so that bats can easily find them," said Michael Schöner of Ernst-Moritz-Arndt-University of Greifswald in Germany. "Moreover, the bats are clearly able to distinguish their plant partner from other plants that are similar in shape but lack the conspicuous reflector."
The findings could also help explain how these Nepenthes hemsleyana plants survive even though they have less luck attracting insects than other pitcher plant species.
To make their findings, a team of researchers used an artificial biomimetic bat head that emits and records ultrasounds to determine the acoustic reflectivity of the pitcher plants. The experiment revealed a strong echo reflection from the pitchers' back walls. Further behavioral experiments showed bats were better at finding partially hidden pitcher plants with fully intact reflector walls, as opposed to when this mechanism had been inhibited. The bats were also more likely to choose a pitcher plant as a roosting spot if its reflector had not been reduced.
"Carnivorous plants in general have already solved the problem of nutrient deficiency in a very unusual way by reversing the 'normal system' of animals feeding on plants," Schöner said. "It is even more astonishing that in the case of N. hemsleyana the system is taking a new turn. While N. hemsleyana reduced many insect-attracting traits, it obviously exhibits some traits that are highly attractive for a species that provides the plants with nutrients without being digested by the plant itself."
The findings were published in a recent edition of the journal Current Biology.
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