Title

Design and performance of amphibian middle ears

Poster Number

35

Lead Author Major

Biological Sciences and Pre-Dentistry

Format

Poster Presentation

Faculty Mentor Name

Marcos Gridi-Papp

Faculty Mentor Department

Biological Sciences

Abstract/Artist Statement

An inverse relationship is found between the body sizes of frogs and the sound frequencies that they can hear. This relationship can be distorted, however, by species with uncommon auditory morphology. Such cases are generally informative about auditory design and evolution. We compared the form and function of the middle ears in four species of frogs from different families and geographic distribution: Rana pipiens (Ranidae; North America), Engystomops pustulosus (Leiuperidae; Central America), Hyla versicolor (Hylidae; North America), and Leptopelis flavomaculatus (Hyperoliidae; Africa). Dissections were conducted to isolate the middle ears of the individual species. To compare their auditory morphology, histological methods were employed producing slides, which allowed for precise measurement of the eardrum and other middle ear structures. Measurements were taken from single images or three-dimensional reconstructions of the middle ear. These data were analyzed alongside laser vibrometry data generated by other researchers in our lab, recording the sensitivity and tuning of the middle ears to sound. The morphological proportions of the middle ear structures were similar among R. pipiens, L. flavomaculatus, and H. versicolor and in agreement with their body size and tuning. The tiny E. Pustulosus, however, is tuned to lower frequencies than would be predicted by its body size. Their middle ears contain a greatly expanded cartilaginous disk attached to the eardrum. This structure should load the eardrum and make it vibrate at low frequencies. The modified tuning in túngara frogs has been shown to have greatly influenced the evolution of its calling and reproductive behavior.

Location

DeRosa University Center, Ballroom

Start Date

20-4-2013 1:00 PM

End Date

20-4-2013 3:00 PM

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Apr 20th, 1:00 PM Apr 20th, 3:00 PM

Design and performance of amphibian middle ears

DeRosa University Center, Ballroom

An inverse relationship is found between the body sizes of frogs and the sound frequencies that they can hear. This relationship can be distorted, however, by species with uncommon auditory morphology. Such cases are generally informative about auditory design and evolution. We compared the form and function of the middle ears in four species of frogs from different families and geographic distribution: Rana pipiens (Ranidae; North America), Engystomops pustulosus (Leiuperidae; Central America), Hyla versicolor (Hylidae; North America), and Leptopelis flavomaculatus (Hyperoliidae; Africa). Dissections were conducted to isolate the middle ears of the individual species. To compare their auditory morphology, histological methods were employed producing slides, which allowed for precise measurement of the eardrum and other middle ear structures. Measurements were taken from single images or three-dimensional reconstructions of the middle ear. These data were analyzed alongside laser vibrometry data generated by other researchers in our lab, recording the sensitivity and tuning of the middle ears to sound. The morphological proportions of the middle ear structures were similar among R. pipiens, L. flavomaculatus, and H. versicolor and in agreement with their body size and tuning. The tiny E. Pustulosus, however, is tuned to lower frequencies than would be predicted by its body size. Their middle ears contain a greatly expanded cartilaginous disk attached to the eardrum. This structure should load the eardrum and make it vibrate at low frequencies. The modified tuning in túngara frogs has been shown to have greatly influenced the evolution of its calling and reproductive behavior.