title: Frequency tuning and directional sensitivity of tympanal vibrations in the field cricketGryllus bimaculatus.
abstract: Female field crickets use phonotaxis to locate males by their calling song. Male song production and female behavioural sensitivity form a pair of matched frequency filters, which inGryllus bimaculatusare tuned to a frequency of about 4.7 kHz. Directional sensitivity is supported by an elaborate system of acoustic tracheae, which make the ears function as pressure difference receivers. As a result, phase differences between left and right sound inputs are transformed into vibration amplitude differences. Here we critically tested the hypothesis that acoustic properties of internal transmissions play a major role in tuning directional sensitivity to the calling song frequency, by measuring tympanal vibrations as a function of sound direction and frequency. Rather than sharp frequency tuning of directional sensitivity corresponding to the calling song, we found broad frequency tuning, with optima shifted to higher frequencies. These findings agree with predictions from a vector summation model for combining external and internal sounds. We show that the model provides robust directional sensitivity that is, however, broadly tuned with an optimum well above the calling song frequency. We therefore advocate that additional filtering, e.g. at a higher (neuronal) level, significantly contributes to frequency tuning of directional sensitivity.
authors.affiliation: Experimental Zoology Group, Department of Animal Sciences, Wageningen University, De Elst 1, Wageningen, The Netherlands martin.lankheet@wur.nl.
authors.forename: Martin J
authors.identifier: 0000-0002-8261-2187
authors.initials: MJ
authors.lastname: Lankheet
authors.affiliation: Experimental Zoology Group, Department of Animal Sciences, Wageningen University, De Elst 1, Wageningen, The Netherlands.
authors.forename: Uroš
authors.initials: U
authors.lastname: Cerkvenik
authors.affiliation: Sound and Behavior Group, Department of Biology, University of Southern Denmark, Campusvej 55, Odense M, Denmark.
authors.forename: Ole N
authors.initials: ON
authors.lastname: Larsen
authors.affiliation: Experimental Zoology Group, Department of Animal Sciences, Wageningen University, De Elst 1, Wageningen, The Netherlands.
authors.forename: Johan L
authors.initials: JL
authors.lastname: van Leeuwen
mesh_terms: D000818:Animals; D005260:Female; D006135:Gryllidae / Q000502:physiology*; D008297:Male; D008954:Models, Biological; D014828:Vocalization, Animal / Q000502:physiology*
keywords: directional hearing; laser Doppler vibrometer; phase shift; phonotaxis; pressure difference receiver