Like Batman is drawn to his symbol, a certain rainforest vine pollinated by bats has evolved to grow dish-shaped leaves that attract the winged creatures using echolocation.
According to a study published in Science magazine, the leaf echo draws bats to the vine's flowers twice as fast as it would without the echo.
Typically, birds and bees are attracted to brightly colored flowers. Far less research has been done as to whether plants using echolocation to attract bats for pollination and seed dispersal have developed analogous echo-acoustic signals.
However, the Cuban rainforest vine Marcgravia evenia has managed to evolve concave leaves, which researchers say resemble a dish reflector. After analyzing the leaf's acoustic properties, the researchers found that it acts as an echo beacon, providing an unchanging acoustic signature to attract bats.
To determine whether this echolocation attracted bats more quickly, researchers hid a small feeder filled with nectar among artificial foliage some with the specially shaped leaf, and others without. Each feeder was tested one at each of the 64 positions within the artificial foliage.
It took the bats the longest to locate the nectar feeder when it was placed on its own rather than when it was placed with the specially shaped leaf. The scientists concluded that when the dish-shaped leaf was located above the feeder, it helped reduce search times by around 50%.
The paper's co-author, Dr Marc Holderied of Bristol's School of Biological Sciences said, "This echo beacon has benefits for both the plant and the bats. On one hand, it increases the foraging efficiency of nectar-feeding bats, which is of particular importance as they have to pay hundreds of visits to flowers each night to fulfill their energy needs. On the other hand, the M. evenia vine occurs in such low abundance that it requires highly mobile pollinators."