Honors College Capstone Experience/Thesis Projects

Department

Biology

Document Type

Thesis

Abstract

The net-spinning caddisfly Hydropsyche simulans can be a common inhabitant of shallow reaches in riverine systems, and is easily the most common hydropsychid in the upper Green River, Kentucky. This study was performed in summer 2011 and focused on two main questions: 1. Do the larvae of the riverine caddisflies H. simulans and Cheumatopsyche preferentially inhabit dense patches of P. ceratophyllum compared to bare substrates in the upper Green River?, and 2. Do larvae of H. simulans and Cheumatopsyche consume the filamentous alga Cladophora during the annual late summer algal bloom in the upper Green River? Densities of both hydropsychid taxa were significantly higher in very high (> 75% areal coverage) P. ceratophyllum habitat. A multi-source mixing model (IsoSource) using both δ13C and δ15N stable isotope data revealed that Cladophora was a prominent assimilated dietary item during August and September, indicating that both taxa can preferentially graze the filamentous alga during seasonal blooms. There appears to be a clear habitat preference for P. ceratophyllum for net-spinning caddisfly larvae, as well as the implication of behavior to switch from grazing off the nets to grazing directly on Cladophora sp. when the resource is abundant during late summer and into early autumn.

Advisor(s) or Committee Chair

Dr. Scott Grubbs

Disciplines

Biology | Plant Sciences | Terrestrial and Aquatic Ecology

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