Plant develops echo to attract bats
London: A rainforest vine has evolved dish-shaped leaves which develop echoes to attract bats for pollination, researchers claim.
The Cuban plant's leaves develop such conspicuous echoes that the bats can discover its flowers twice faster than those without an echo.
Marcgravia evenia has developed a distinctively shaped concave leaf next to its flowers which, the researchers noticed, is reminiscent of a dish reflector, the journal Science reports.
The discovery was made by a team of scientists from universities of Bristol, UK and Erlangen and Ulm, Germany.
"This echo beacon has benefits both for the plant and the bats," says Marc Holderied of Bristol's School of Biological Sciences.
"On one hand, it increases the foraging efficiency of nectar-feeding bats...as they have to pay hundreds of visits to flowers each night to fulfill their energy needs," Holderied says.
"On the other hand, the M. evenia vine occurs in such low abundance that it requires highly mobile pollinators," he added.
By analysing the leaf's sound reflection properties, researchers found that it acts as an ideal echo beacon, sending back strong, multi-directional echoes with an easily recognizable, and unvarying acoustic signature -- perfect for the bats to home in.
They then trained nectar-feeding bats to search for a single small feeder hidden within an artificial foliage background, varying the feeder's position and measuring the time the bats took to find it.
Search times were the longest for all bats when the feeder was presented on its own and were slightly, but not significantly, shorter when a replica of a foliage leaf was added.
However, a dish-shaped leaf replica above the feeder always reduced search times -- by around 50 percent.