>>Late into the night, a bleary-eyed Geipel watched to see if the common big-eared bat could use its echolocation capabilities to catch the dragonfly, even though the insect wasn’t moving or making any noise.
Most bats target their prey through echolocation, projecting sound waves and sensing the signals that bounce off what’s in front of them. While echolocation is a common feature among ocean animals like whales and dolphins, besides a few bird species, bats are one of the only land animals to use the technique.
Typically, echolocation can’t detect a motionless dragonfly perched on a leaf. The sound waves bouncing off the leaf would drown out any signal coming from the insect itself.
To understand this evolutionary battle, consider the multi-millennia skirmish between bats and moths. Bats love moths: They’re large, nutritious sources of food for an animal that can eat virtually its own body weight in insects each night. Yet because they are such coveted prey among bat species, moths have developed a host of strategies to combat echolocation. Some moth species, for instance, have scales that actually “jam” bat sonar in order to avoid detection. Others have developed ears that can detect echolocation ultrasounds, so the insects can flee before they fall prey to an approaching bat.
Bats have not taken these evolutionary counter-measures lightly. In response, some bat species like the Barbastelle bat began using alternate ultrasound signals, or “stealth echolocation,” that moths cannot detect.
The use of leaves as acoustic mirrors is the latest frontier in the struggle between bats, and their prey.<<
https://www.smithsonianmag.com/smithsonian-institution/bats-use-leaves-as-mirrors-locate-catch-their-prey-180972771/