Date of Award

Fall 2002

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Program/Concentration

Biology

Committee Director

William Resetarits

Committee Member

Alan H. Savitzky

Committee Member

Mark J. Butler

Call Number for Print

Special Collections LD4331.B46 R54 2002

Abstract

Patterns of larval amphibian distribution and abundance have historically been ascribed to direct predation. However, adult oviposition site selection is an alternative mechanism that can produce identical patterns and significantly influence community assembly. Although such behavioral habitat selection has been documented in several amphibian species whose larvae lack particular anti-predator defenses, the sensitivity of adult amphibians in detecting predator cues and avoiding these habitats has not yet been determined. If larval survivorship is greatly reduced in sites containing predatory fish, selection to detect and avoid habitats with low fish densities should be strong. I conducted three experiments which, (1) evaluated the ability of ovipositing pine woods treefrogs (Hyla femoralis), to detect varying densities of a predatory fish (Umbra pygmaea), (2) quantified larval performance under varying densities of these predators, and (3) quantified egg mortality and hatching rate in the presence of U. pygmaea. Both the adult preference and larval performance experiments utilized wading pools in a complete randomized block design with varying treatment levels of predatory U. pygmaea (0-6 individuals). The egg experiment utilized a full factorial randomized block design by crossing two egg densities (20 or 40 eggs) with the presence and absence of U. pygmaea. In the oviposition experiment, fish were caged to eliminate consumption of eggs. However, fish were uncaged in the larval and egg performance experiments. Data from these three experiments suggest that adult oviposition preference matches larval performance. Hyla femoralis females detected very low densities of fish and oviposited in habitats lacking these predators. This behavior resulted in higher offspring survivorship by redistributing eggs into fishless habitats.

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DOI

10.25777/cmms-an85

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