title: Phase shifts in binaural stimuli provide directional cues for sound localisation in the field cricket Gryllus bimaculatus.
abstract: The cricket's auditory system is a highly directional pressure difference receiver whose function is hypothesised to depend on phase relationships between the sound waves propagating through the auditory trachea that connects the left and right hearing organs. We tested this hypothesis by measuring the effect of experimentally constructed phase shifts in acoustic stimuli on phonotactic behavior of Gryllus bimaculatus, the oscillatory response patterns of the tympanic membrane, and the activity of the auditory afferents. The same artificial calling song was played simultaneously at the left and right sides of the cricket, but one sound pattern was shifted in phase by 90 deg (carrier frequencies between 3.6 and 5.4 kHz). All three levels of auditory processing are sensitive to experimentally induced acoustic phase shifts, and the response characteristics are dependent on the carrier frequency of the sound stimulus. At lower frequencies, crickets steered away from the sound leading in phase, while tympanic membrane vibrations and auditory afferent responses were smaller when the ipsilateral sound was leading. In contrast, opposite responses were observed at higher frequencies in all three levels of auditory processing. Minimal responses occurred near the carrier frequency of the cricket's calling song, suggesting a stability at this frequency. Our results indicate that crickets may use directional cues arising from phase shifts in acoustic signals for sound localisation, and that the response properties of pressure difference receivers may be analysed with phase-shifted sound stimuli to further our understanding of how insect auditory systems are adapted for directional processing.
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK Howard Hughes Medical Institute, Janelia Farm Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Seagraves
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK bh202@cam.ac.uk.
authors.forename: Berthold
authors.initials: B
authors.lastname: Hedwig
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D003463:Cues; D005260:Female; D006135:Gryllidae / Q000502:physiology*; D013017:Sound Localization; D014432:Tympanic Membrane / Q000502:physiology
keywords: Auditory orientation; Cricket; Phase shift
references.citation: J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2006 Oct;192(10):1063-72
references.pmid: 16761131
references.citation: J Exp Biol. 2005 Mar;208(Pt 6):1209-17
references.pmid: 15767319
references.citation: Nature. 2004 Aug 12;430(7001):781-5
references.pmid: 15306810
references.citation: Bioinspir Biomim. 2008 Mar;3:011001
references.pmid: 18364558
references.citation: PLoS One. 2010 Dec 08;5(12):e15141
references.pmid: 21170344
references.citation: Hear Res. 2011 Mar;273(1-2):37-45
references.pmid: 20727396
references.citation: Front Zool. 2009 Sep 28;6:22
references.pmid: 19785724
references.citation: Microsc Res Tech. 2004 Apr 15;63(6):351-74
references.pmid: 15252878
references.citation: J Neurosci Methods. 1992 Oct-Nov;45(1-2):135-48
references.pmid: 1491595
references.citation: J Acoust Soc Am. 1979 Aug;66(2):350-7
references.pmid: 512197
references.citation: J Exp Biol. 2005 Mar;208(Pt 5):915-27
references.pmid: 15755890
references.citation: J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2014 Feb;200(2):139-48
references.pmid: 24281354
references.citation: J Neurosci. 1981 Jan;1(1):40-8
references.pmid: 7346557
references.citation: Annu Rev Psychol. 1991;42:135-59
references.pmid: 2018391
references.citation: Naturwissenschaften. 2001 Apr;88(4):159-70
references.pmid: 11480703