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Microphone-Array Tracking of Echolocating Bats Foraging in the Field

2012; Frontiers Media; Volume: 6; Linguagem: Inglês

10.3389/conf.fnbeh.2012.27.00004

1662-5153

Watanabe Yoshiaki,

Marine animal studies overview

Event Abstract Back to Event Microphone-Array Tracking of Echolocating Bats Foraging in the Field Emyo Fujioka1*, Ikkyu Aihara2, Shotaro Watanabe1, Shizuko Hiryu3*, James A. Simmons4, Hiroshi Riquimaroux3 and Yoshiaki Watanabe3 1 Doshisha University, Faculty of Life and Medical Science, Japan 2 RIKEN, Brain Science Institute, Japan 3 Doshisha University, Faculty of Life and Medical Sciences, Neurosensing and Bionavigation Research Center, Japan 4 Brown university, Department of Neuroscience, United States In the field, echolocating Japanese house bats show dynamic and sophisticated sonar performance that can never be seen in the restricted flight chamber in the laboratory. In this study, we recorded ultrasounds of the bats using a super array (10 array-units, consisting of 32-ch microphones) in the field, which allowed us to acoustically track the whole flight path of the bats foraging for long-time. The directional aim of the sonar sounds was also measured simultaneously with temporal structure of ultrasound sequence and orbital characteristics. The microphones were put on river sides and on a bridge toward a small stream (22 m width) in Kyotanabe, Japan, where the bats have been observed to forage for flying insects repeatedly. Three-dimensional flight paths of the bats were reconstructed by calculating sounds’ arrival-time differences between pairs of microphones in 4 Y-shaped units. Microphone array can provide not only locations where the bats emit sonar sounds but also timing of the pulse emission and prey capture. Prey captures were repeatedly observed at least every 20 s even at low rate of repetitive prey capture. Inversely, when the capturing rate was high, the bats captured insects repeatedly every 2-3 s. Pulse emissions were shifted between two or three particular directions in an alternating manner; i.e., the bats attended to get information about the second target before capturing the first one, or the bats alternately scanned between the flying direction and the previous capture point. This finding suggests that the foraging bats process multiple echo streams from different directions by shifting their search direction with time-sharing manner. Interpulse interval (IPI) of each flight distributed at around 90-100 ms which almost does not vary with the capturing rate during insect search. However, interestingly, weak second peak was observed in IPI distribution over the IPI of 150 ms (long IPI) when the capturing rate was low. We set a boundary at 150 ms to divide observed IPIs into two populations; normal IPI (< 150 ms) and long IPI (> 150 ms). Averages of normal and long IPIs are 89.5 ± 15.8 ms and 174.0 ± 19.9 ms respectively. Additionally, as the capturing rate decreases, the long IPIs were frequently occurred and the track gets simple looping search pattern. Here we hypothesize that the looping search pattern with the occasional long IPI which is used by the bats is effective for a target search. We also demonstrated these effects by mathematical calculation. As a result of the calculation of search areas, we suggest that bat’s circular motion with occasional long IPIs is stochastically effective for target search compared to random, correlated random and linear motions. Acknowledgements Research supported by a Grant-in-Aid for Scientific Research on Innovative Areas (Grant No. 20200055), a Grant-in-Aid for Young Scientists (B) (Grant No. 21760318) of JSPS, and an Office of Naval Research (ONR) grant. Keywords: Bio-sonar, Flight path, interpulse interval, Target search, Time sharing processing Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for student poster award) Topic: Orientation and Navigation Citation: Fujioka E, Aihara I, Watanabe S, Hiryu S, Simmons JA, Riquimaroux H and Watanabe Y (2012). Microphone-Array Tracking of Echolocating Bats Foraging in the Field. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00004 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 May 2012; Published Online: 07 Jul 2012. * Correspondence: Mr. Emyo Fujioka, Doshisha University, Faculty of Life and Medical Science, Kyotanabe, Kyoto, 610-0394, Japan, emj1101@mail4.doshisha.ac.jp Dr. Shizuko Hiryu, Doshisha University, Faculty of Life and Medical Sciences, Neurosensing and Bionavigation Research Center, Kyotanabe, Kyoto, 610-0394, Japan, shiryu@mail.doshisha.ac.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Emyo Fujioka Ikkyu Aihara Shotaro Watanabe Shizuko Hiryu James A Simmons Hiroshi Riquimaroux Yoshiaki Watanabe Google Emyo Fujioka Ikkyu Aihara Shotaro Watanabe Shizuko Hiryu James A Simmons Hiroshi Riquimaroux Yoshiaki Watanabe Google Scholar Emyo Fujioka Ikkyu Aihara Shotaro Watanabe Shizuko Hiryu James A Simmons Hiroshi Riquimaroux Yoshiaki Watanabe PubMed Emyo Fujioka Ikkyu Aihara Shotaro Watanabe Shizuko Hiryu James A Simmons Hiroshi Riquimaroux Yoshiaki Watanabe Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.