December 12, 2013
Nectar Bat Uses Stealthy Moves To Catch Its Evening Dinner
Lee Rannals for redOrbit.com - Your Universe Online
New research shows the Pallas long-tongued bat is a very stealthy predator when it comes to catching insects.
Previously, scientists believed the nectar-feeding bat ate insects in passing, but the latest research shows it targets its moving prey with stealthy precision. The team proved for the first time that the Pallas long-tongued bat uses a stealthier form of echolocation.
Echolocation is a physical trait that involves the production, reception and auditory processing of ultrasonic pulses for detecting unseen obstacles or tracking down prey. Most bats produce a rapid sequence of echolocation pulses to attack their prey and many insects have developed ears to detect bats helping them to avoid being caught. However, the latest study reveals the Pallas long-tongued bat has an even more modern form of echolocation that is capable of thwarting even the most well-equipped prey.
A genetic analysis of the bat’s food waste showed it was consuming a type of moth that should be sensitive to being captured by echolocation. The scientists had to use sound recordings and infrared video to monitor the bats and determine how they were approaching their insects. This method allowed the team to spy on how the bats were detecting and approaching tethered mealworms.
The team, publishing a paper in the journal Functional Ecology, wrote they found the bat’s echolocation calls were high in frequency but low in intensity, making it difficult for its prey to detect the imminent danger, even if they were equipped with the bat-detecting ears.
"When we compared the bats' echolocation calls to the moths' auditory abilities, we found that the low intensity echolocation calls were not loud enough to trigger the auditory neurons of moths with ears," Dr Elizabeth Clare, from Queen Mary's School of Biological and Chemical Sciences, said in a statement. "In effect, the echolocation of Pallas's long-tongued bats is too quiet for the moths to hear and allows them to sneak up on their target using a stealth tactic."
The Pallas long-tongued bats are an important pollinator in Central and South America. The bats belong to a group that are often called “whispering bats” because they emit relatively quiet echolocation calls to forage within dense vegetation.
The findings mean the European barbastelle bat is not the only stealthy bat in business. Scientists have known this bat uses stealth echolocation to sneak up on its insects, but this study provides implications that there could be other sneaky predators out there as well.
"Our analysis suggests there might be more bats than previously thought that benefit from this stealthy approach that prevents prey from escaping by listening for bats,” Clare said.