Graduate Program

Environmental Biology

Degree Name

Master of Science (MS)

Semester of Degree Completion

1994

Thesis Director

Michael Goodrich

Abstract

The effectiveness of the skin secretions of Notophthalmus viridescens as a predator deterrent has been well documented. Still, there have been documented cases of predation on this salamander. This study investigates the ability of a variety of herptiles to feed on N. viridescens louisianensis.

In the first experiment, plethodonts and efts were fed on alternate weeks to snakes. Latency of response, anatomical location of predator attack, and behaviors displayed by predators and prey were recorded during each trial.

In the second experiment, tongue flick frequency by T. sirtalis to the essence of live N. viridescens louisianensis, Eurycea cirigerra, thawed larval Ambystoma tigrinum, and water was recorded. Tongue flicks to the four stimuli were compared at three satiation levels to determine if hunger might alter prey selection by snakes.

Only Heterodon platyrhinos was found to accept efts as readily as controls. Chrysemys picta was found to accept efts and controls initially, but later refused all salamanders. T. sirtalis accepted efts and plethodonts with equal readiness.

Plethodontidae displayed tail wrapping, thrashing, autotomy, and a new behavior called crawling. Efts displayed slow walking after an attack and unken reflex while in the grasp of a snake. Unken reflex was not observed predicating an attack. Unken reflex, tail wrapping, and location of snake attack were found to increase swallowing times.

As hunger increased, so did tongue flick rate. Stimulus type affected tongue flick rate. Satiation level did not significantly interact with prey preference.

It appears that the skin secretions of N. viridescens louisianensis are a predation deterrent, but some predators can and will eat them.

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