Calling Bats
Plants may seem quiet, but some use sound to call bats.
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More than 500 plants depend on bats for pollination, including bananas.
The sounds hit a curved leaf.
A bat makes high-pitched sounds as it fl ies.
The sounds echo off the leaf.
The bat follows the echoes to the fl ower.
Following an Echo To understand how a flower could call a bat, it helps to know how bats find their way. T ey use their ears to “see” in the dark. T ey follow a trail of sounds. As a bat flies, it makes a series of calls that
are so high-pitched that we can’t hear them. Bats can, though. Sound waves from these calls bounce, or reflect, off objects and then back to the bat like an echo. T e bat listens for these echoes. T ey tell the bat what objects are in front of it and where these objects are. T is echolocation is a bat’s most important sense. Bats use echoes not just to avoid bumping
into objects, but also to find them. Bats that eat insects, for instance, use echoes to track mosquitoes and moths. Simon argues that the same thing may be true of bats that drink nectar. T ey use echoes to find flowers.
A Bat Experiment To test this theory, Simon did experiments in his lab. He hung feeders filled with nectar. T en he placed fake leaves over them. Some leaves were flat. Some leaves were curved. Simon knew that more echoes bounce off a curved surface than a flat surface. So the echoes from a curved leaf are stronger. T en Simon released bats into his lab. He
watched to see if the shape of the leaves made a diff erence. It did! Bats found the feeders under the curved leaves 50 percent faster than they found the ones under the flat leaves. It took them only 12 seconds. Simon supported his claim in the lab. Next,
he wanted to find evidence in the wild. T at’s why we’re in the jungle. We’re searching for flowers that bats pollinate. We want to see if they have parts that can call bats.
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