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Sex-Biased Predation on Taricha by a Novel Predator in Annadel State Park

by Brouillette, Amber Noelle

Abstract (Summary)
Newts of the genus Taricha have long been studied due to the powerful neurotoxin found in their skin. Tetrodotoxin (TTX) acts by blocking receptors in sodium channels, ultimately resulting in death via asphyxiation. The only documented predators of species in this genus have been snakes of the genus Thamnophis. Recently, predation on Taricha in Ledson Marsh in Annadel State Park, Santa Rosa, CA was discovered. Predation was in the form of laceration or evisceration, and tracking of predation from 1998-2008 showed that it was male-biased. Two species of Taricha were found living sympatrically at this location, the California newt (T. torosa) and the rough-skinned newt (T. granulosa). Fluorometric High Phase Liquid Chromatography (HPLC) analysis was used in order to quantify TTX levels in the skin of ten male and ten female newts of each species. Quantification of TTX was done to determine the influence, if any, that TTX levels may have on sex-biased predation in this population. I predicted that levels of TTX would be greater in females than males, and greater in T. granulosa than T. torosa since very few T. granulosa were preyed upon during the study period. My results indicated that there were significant differences between the sexes, and T. torosa were significantly more toxic than T. granulosa. An in-depth ecological study of relative abundances of both species and identification of the predator are needed at this site to obtain a clear picture of the predator-prey dynamics at Ledson Marsh
Bibliographical Information:

Advisor:

School:Utah State University

School Location:USA - Utah

Source Type:Master's Thesis

Keywords:annadel state park taricha granulosa torosa sex biased predation tetrodotoxin evisceration

ISBN:

Date of Publication:12/01/2008

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