Neural auditory tuning in túngara frogs (Engystomops pustulosus)
Poster Number
26
Format
Poster Presentation
Faculty Mentor Name
Marcos Gridi-Papp
Faculty Mentor Department
Biological Sciences
Abstract/Artist Statement
Túngara frogs rely primarily on acoustic advertisement calls to find a mate. These calls consist of a lower frequency whine from 400-900 Hz essential for species recognition followed by an optional higher frequency chuck near 2500 Hz. In most species of frogs, the hearing pathway is tuned to have maximal auditory sensitivity at the species’ peak vocalization frequencies. In some amphibians, extratympanic hearing structures, such as the lungs and body wall, serve as sensory organs for auditory stimuli. This research sought to verify the neural hearing sensitivity of túngara frogs by recording auditory evoked potential production in the torus semicircularis in response to a tone sweep. The recorded neural response matched the calling frequencies with peak sensitivity near 400 Hz with a secondary peak ranging from 2000-3000 Hz. However, characterizations of túngara eardrum sensitivity in our lab show peak response near the chuck frequency. Further research will attempt to elucidate the source of the tuning disparity. It is possible that túngara frogs may hear low frequency sounds disproportionately through their body walls, but past measurements of the mechanical sensitivity appear to belie the theory. Factors immanent to the calling environment may also influence sensitivity. First, with many competing species present in the mating area, túngara rely on the order of frequency presentation to prevent energetically wasteful inter-species mating. Second, túngara calls are made from the water where ovulating females swim with their eardrums at least partially submerged in water. This acoustic environment may produce significantly different aural sensitivity and explain the tuning disparity found when performing terrestrial measurements.
Location
DeRosa University Center, Ballroom
Start Date
25-4-2015 10:00 AM
End Date
25-4-2015 12:00 PM
Neural auditory tuning in túngara frogs (Engystomops pustulosus)
DeRosa University Center, Ballroom
Túngara frogs rely primarily on acoustic advertisement calls to find a mate. These calls consist of a lower frequency whine from 400-900 Hz essential for species recognition followed by an optional higher frequency chuck near 2500 Hz. In most species of frogs, the hearing pathway is tuned to have maximal auditory sensitivity at the species’ peak vocalization frequencies. In some amphibians, extratympanic hearing structures, such as the lungs and body wall, serve as sensory organs for auditory stimuli. This research sought to verify the neural hearing sensitivity of túngara frogs by recording auditory evoked potential production in the torus semicircularis in response to a tone sweep. The recorded neural response matched the calling frequencies with peak sensitivity near 400 Hz with a secondary peak ranging from 2000-3000 Hz. However, characterizations of túngara eardrum sensitivity in our lab show peak response near the chuck frequency. Further research will attempt to elucidate the source of the tuning disparity. It is possible that túngara frogs may hear low frequency sounds disproportionately through their body walls, but past measurements of the mechanical sensitivity appear to belie the theory. Factors immanent to the calling environment may also influence sensitivity. First, with many competing species present in the mating area, túngara rely on the order of frequency presentation to prevent energetically wasteful inter-species mating. Second, túngara calls are made from the water where ovulating females swim with their eardrums at least partially submerged in water. This acoustic environment may produce significantly different aural sensitivity and explain the tuning disparity found when performing terrestrial measurements.