Quantifying tetrodotoxin levels in the California newt using a non-destructive sampling method.
Toxic or noxious substances often serve as a means of chemical defense for numerous taxa. However, such compounds may also facilitate ecological or evolutionary processes. The neurotoxin, tetrodotoxin (TTX), which is found in newts of the genus Taricha, acts as a selection pressure upon predatory garter snakes, is a chemical cue to conspecific larvae, which elicits antipredator behavior, and may also affect macroinvertebrate foraging behavior. To understand selection patterns and how potential variation might affect ecological and evolutionary processes, it is necessary to quantify TTX levels within individuals and populations. To do so has often required that animals be destructively sampled or removed from breeding habitats and brought into the laboratory. Here we demonstrate a non-destructive method of sampling adult Taricha that obviates the need to capture and collect individuals. We also show that embryos from oviposited California newt (Taricha torosa) egg masses can be individually sampled and TTX quantified from embryos. We employed three different extraction techniques to isolate TTX. Using a custom fabricated high performance liquid chromatography (HPLC) system we quantified recovery of TTX. We found that a newly developed micro-extraction technique significantly improved recovery compared to previously used methods. Results also indicate our improvements to the HPLC method have high repeatability and increased sensitivity, with a detection limit of 48 pg (0.15 pmol) TTX. The quantified amounts of TTX in adult newts suggest fine geographic variation in toxin levels between sampling localities isolated by as little as 3 km.
University of California Los Angeles, Department of Ecology and Evolutionary Biology, 612 Charles E. Young Drive East, Los Angeles, CA 90095, USA. Electronic address: garyb@ucla.edu.
Gary M
GM
Bucciarelli
Pepperdine University, Department of Chemistry, 24255 Pacific Coast Highway, Malibu, CA 90265, USA.
Amy
A
Li
University of California Los Angeles, Department of Ecology and Evolutionary Biology, 612 Charles E. Young Drive East, Los Angeles, CA 90095, USA.
Richard K
RK
Zimmer
Pepperdine University, Department of Biology, 24255 Pacific Coast Highway, Malibu, CA 90265, USA.
Lee B
LB
Kats
Pepperdine University, Department of Chemistry, 24255 Pacific Coast Highway, Malibu, CA 90265, USA.
David B
DB
Green
D000818:Animals; D005075:Biological Evolution; D002140:California; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D017812:Colubridae; D007814:Larva / Q000737:chemistry; D008297:Male; D010063:Ovum / Q000737:chemistry; D011235:Predatory Behavior; D012455:Salamandridae; D012867:Skin / Q000737:chemistry; D013779:Tetrodotoxin / Q000032:analysis*
D013779:Tetrodotoxin
HPLC; Non-destructive sampling; Santa Monica Mountains; TTX; Taricha