Date of Award


Degree Type


Degree Name

Departmental Honors




Dry mass/wet mass ratios are essential for estimating energy flow through ecosystems, determining energy budgets, and studying energy allocation in organisms. Preserving specimens by freezing or storing them in ethanol has known effects on the wet mass measurements. These storage methods are used regardless of their effects - altering the wet mass and thereby changing the mass ratio for the organism. We evaluated the effects of ethanol storage and freezing on six different taxa from the Interrnountain West: Hesperoperla, lsoperla, Rhithrogena, Drunella, Arctopsyche, and Rhyacophila. All the taxa studied except Hesperoperla and Rhyacophila showed a significant loss in wet mass when treated with ethanol, with organisms retaining only 17.7% - 79.9% of their original wet mass. Freezing had varied effects. Only Rhithrogena and Drunella showed significant losses in wet mass after being frozen (retaining 29.8% - 45.9% of their original wet mass). Hesperoperla, lsoperla, and Arctopsyche showed no significant loss or gain in wet mass after treatment. Rhyacophila was the only taxa to have a significant mass gain after being frozen, taking on an additional 23% of its original wet mass. Freezing specimens had less of an impact on their wet mass than storing them in ethanol. Dry masses were not significantly affected by either treatment.

Included in

Biology Commons



Faculty Mentor

Scott Miller

Departmental Honors Advisor

Kimberly Sullivan