Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Being all ear: Horseshoe bats use multiple streams of acoustic information simultaneously

30.04.2018

Bats do not only use the information of their echolocation calls for foraging but may also simultaneously analyse acoustic signals from their potential prey. Researchers of the Max Planck Institute for Ornithology in Seewiesen found that Greater Horseshoe bats use such combined acoustic stimuli to considerably extend the limited reach of their echolocation calls.

Bats depend on their echolocation system for foraging at night. They use the calls for spatial orientation and often also for detection and capture of their prey. So does the Greater Horseshoe bat, specialized to hunt for fluttering insects within dense vegetation.


Greater horseshoe bats are specialized in capturing fluttering insects.

© MerlinTuttle.org

For foraging, the bats continuously emit calls with long constant-frequency components. If these calls meet a fluttering insect, the echo obtains a rhythmic pattern caused by the up- and down-beating wings of the insect, which the bats use to recognize their prey.

However, this highly specialized echolocation system is both, spatially and temporarily severely limited: the stroboscopic and highly directional emission of the calls and the strong atmospheric attenuation of ultrasonic frequencies limits the space that can be probed.

Researchers of the Max Planck Institute for Ornithology in Seewiesen now found that the greater horseshoe bats employ passive hearing to initially detect and localize prey-generated and other environmental sounds, and then raise vocalization level and direct their calls on the sound source for further investigation.

Therefore, the animals are capable of processing multiple streams of acoustic information simultaneously and to use this capability for foraging and predator detection.

For the study, the researchers constructed an array of eight microphones in defined distance to a bats‘ perch in a flight room to measure the direction of the echolocation calls. Additionally, they installed three loudspeakers to play back noises of fluttering insects walking over dry leaves. The bats reacted to the noises of this simulated prey by actively directing their calls in this direction and by increasing their call intensity.

In addition to rustling noises of real insects, the researchers also played back rustling noises that had previously been electronically modified. “Contrary to our predictions, the bats also reacted to noises that obviously did not originate from a potential prey”, says Ella Lattenkamp, first author of the study.

„They still raised their vocal attention, probably to check if the noise originate from a predator”, she adds.

The passive hearing of prey noises is the phylogenetically older and less specialized way of foraging. „We presume that passive hearing supported the evolution of sensory specializations and is still compensating for their limitations”, says Holger Goerlitz, research group leader in Seewiesen.

How the simultaneous incoming passive and active auditory information is processed remains now an interesting question for a better understanding of the evolution of sensory systems.

Kontakt:
Dr. Holger R. Goerlitz
Max-Planck-Institut für Ornithologie, Seewiesen
Forschungsgruppe Akustische und Funktionelle Ökologie
Eberhard-Gwinner-Strasse
82319 Seewiesen
Email: hgoerlitz@orn.mpg.de
Tel: +49 8157 932-372

Publication:
Environmental acoustic cues guide the biosonar attention of a highly specialised echolocator
Ella Z. Lattenkamp, Samuel Kaiser, Rožle Kaučič, Martina Großmann, Klemen Koselj, Holger R. Goerlitz
Journal of Experimental Biology 2018 221: jeb165696 doi: 10.1242/jeb.165696

Weitere Informationen:

http://jeb.biologists.org/content/221/8/jeb165696

Dr. Sabine Spehn | Max-Planck-Institut für Ornithologie
Further information:
http://www.orn.mpg.de

More articles from Life Sciences:

nachricht Microscope measures muscle weakness
16.11.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Good preparation is half the digestion
16.11.2018 | Max-Planck-Institut für Stoffwechselforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Purdue cancer identity technology makes it easier to find a tumor's 'address'

16.11.2018 | Health and Medicine

Good preparation is half the digestion

16.11.2018 | Life Sciences

Microscope measures muscle weakness

16.11.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>