title: A novel acoustic-vibratory multimodal duet.
abstract: The communication strategy of most crickets and bushcrickets typically consists of males broadcasting loud acoustic calling songs, while females perform phonotaxis, moving towards the source of the call. Males of the pseudophylline bushcricket species Onomarchus uninotatus produce an unusually low-pitched call, and we found that the immediate and most robust response of females to the male acoustic call was a bodily vibration, or tremulation, following each syllable of the call. We hypothesized that these bodily oscillations might send out a vibrational signal along the substrate on which the female stands, which males could use to localize her position. We quantified these vibrational signals using a laser vibrometer and found a clear phase relationship of alternation between the chirps of the male acoustic call and the female vibrational response. This system therefore constitutes a novel multimodal duet with a reliable temporal structure. We also found that males could localize the source of vibration but only if both the acoustic and vibratory components of the duet were played back. This unique multimodal duetting system may have evolved in response to higher levels of bat predation on searching bushcricket females than calling males, shifting part of the risk associated with partner localization onto the male. This is the first known example of bushcricket female tremulation in response to a long-range male acoustic signal and the first known example of a multimodal duet among animals.
authors.affiliation: Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India Centre for Neural and Cognitive Sciences, Hyderabad Central University, Gachibowli, Hyderabad 500046, India kaveri.indira@gmail.com.
authors.forename: Kaveri
authors.initials: K
authors.lastname: Rajaraman
authors.affiliation: Centre for Nano Science and Engineering and Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Vamsy
authors.initials: V
authors.lastname: Godthi
authors.affiliation: Centre for Nano Science and Engineering and Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Rudra
authors.initials: R
authors.lastname: Pratap
authors.affiliation: Centre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Rohini
authors.initials: R
authors.lastname: Balakrishnan
mesh_terms: D000819:Animal Communication; D000818:Animals; D001070:Appetitive Behavior; D005260:Female; D006135:Gryllidae / Q000502:physiology*; D008297:Male; D012726:Sexual Behavior, Animal; D014732:Vibration
keywords: Bushcricket; Katydid; Onomarchus; Phonotaxis; Tremulation; Vibration