Date of Award

6-2022

Document Type

Restricted (Opt-Out)

Degree Name

Bachelor of Science

Department

Biology

First Advisor

Scott Kirkton

Keywords

Grasshopper, lactate, exercise, animal physiology, respiratory system, tracheal system, insect, development

Abstract

Insects are the most evolutionarily successful animals in part due to their air-filled tracheal respiratory system. During intermolt periods, the American locust (Schistocerca americana) doubles their body mass, which may compress the tracheae and reduce both oxygen delivery and jump performance. We forced early-stage (day 2) and late-stage (day 8) 6th instar grasshoppers to jump in artificial oxygen atmospheres (5%, 10%, 21%, 40% oxygen: balance nitrogen). After jumping, grasshoppers were immediately frozen in liquid nitrogen for a fluorometric lactate assay. We predicted that if oxygen delivery is compromised during development, then late-stage grasshopper jump rate and lactate production would correlate with oxygen level.

Within the first one to two minutes of jumping, there were no significant differences in jump rate between ages at any oxygen level. Previous work has also shown that the first two minutes of jumping is fueled primarily by anaerobic ATP production. At moderate hypoxia (10% O2) and normoxia (21% O2), there were no differences in jump rate by age. In extreme hypoxia (5% O2), late-stage grasshoppers had a 1.6-fold lower average jump rate in minutes three through five. In hyperoxia (40% O2), late-instar grasshoppers' jump rates increased on average by 1.4-fold in minutes two through five.

Late-instar grasshopper muscles produced significantly greater lactate regardless of oxygen level. Within each group, oxygen level did not significantly affect lactateproduction. Continued research will examine how age and oxygen level impact HIF-1 expression in grasshoppers. We predict late-stage grasshoppers will have elevated HIF-1 protein levels.

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Rights Statement

In Copyright - Educational Use Permitted.