Presenter Information

Eve ChristyFollow

Location

Schewel 232

Access Type

Campus Access Only

Presentation Type

Oral Presentation

Start Date

4-4-2018 11:15 AM

Department

Biology

Abstract

The waterfall-climbing goby endemic to Japan, Sicyopterus japonicus, exhibit an amphidromous life history, in which larvae are swept downstream to the ocean upon hatching. After growing for several months, post-larvae return into stream habitats where they undergo metamorphosis and grow to become reproductive individuals. During upstream migration, the post-larvae actively climb up the waterfalls, height of which range between 100 to 1000 times body length, using their mouth and pelvic sucker to generate negative pressure relative to the ambient pressure for adhesion. Adults may stay capable of producing pressure differentials to outcompete non-climbing competitors for resources and repopulate upstream after catastrophic flash flooding events. During ontogeny, S. japonicus exhibits an allometric increase in suction force for adhesion. Adult S. japonicus produces greater force (approximately four times their body weight) than juveniles during climbing. In this study, we examined how pelvic muscles function to generate pressure differentials for adhesion and their physiological fatigability. Using pressure differentials generated by S. japonicus while climbing as an input variable for the decay equation, we calculated the time constant (T) for reduction in suction force. In testing our hypothesis that body size correlate with the time constant, we discuss the implication of our experimental results.

Faculty Mentor

Takashi Maie, Ph.D.

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Apr 4th, 11:15 AM

Locomotor Biomechanics in Waterfall-Climbing Gobiid, Sicyopterus japonicus: Adhesive Force and Fatigue

Schewel 232

The waterfall-climbing goby endemic to Japan, Sicyopterus japonicus, exhibit an amphidromous life history, in which larvae are swept downstream to the ocean upon hatching. After growing for several months, post-larvae return into stream habitats where they undergo metamorphosis and grow to become reproductive individuals. During upstream migration, the post-larvae actively climb up the waterfalls, height of which range between 100 to 1000 times body length, using their mouth and pelvic sucker to generate negative pressure relative to the ambient pressure for adhesion. Adults may stay capable of producing pressure differentials to outcompete non-climbing competitors for resources and repopulate upstream after catastrophic flash flooding events. During ontogeny, S. japonicus exhibits an allometric increase in suction force for adhesion. Adult S. japonicus produces greater force (approximately four times their body weight) than juveniles during climbing. In this study, we examined how pelvic muscles function to generate pressure differentials for adhesion and their physiological fatigability. Using pressure differentials generated by S. japonicus while climbing as an input variable for the decay equation, we calculated the time constant (T) for reduction in suction force. In testing our hypothesis that body size correlate with the time constant, we discuss the implication of our experimental results.