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Thamnophis sirtalis
Snake Board
Regurgitated Adult N. viridescens
Foraging Ecology & TTX Resistance in Thamnophis sirtalis:
Toxin resistance, in which consumers evolve resistance to toxins in their food, is observable in predator-prey and plant-herbivore interactions. Consumer specialization on a food type has been used to explain toxin evolution due to constraint on the consumer to coevolve with toxic defenses in the food organism. Alternatively, consumers may specialize on a food type because they possess the ability to cope with the toxic compounds, where others consumers cannot. A specialist interaction may not be necessary for the evolution of toxin resistance, however. Garter snakes (Thamnophis) have evolved toxin resistance, but seem to consume toxic prey infrequently. With this departure from the established expectation it raises the question, what other ecological factors could influence selection on toxin resistance? For my dissertation I am a exploring the effect local foraging ecology can have on the evolution of toxin resistance.
I am investigating an eastern population of Thamnophis sirtalis at Mountain Lake Biological Station, Virginia where I am specifically examining:
(1) Has this population evolved
resistance to TTX found in local prey (Notophthalmus viridescens)?
(2) What are congenital responses toward local prey?
(3) Are there genotypic correlations in prey response that could constrain
prey recognition?
(4) How does food experience alter prey biases?
To answer these questions I am conducting
survey's of local diet, behavioral assays to investigate prey recognition
response, performance assays to test for TTX resistance, and sequencing analysis
to examine the mechanism of resistance in this population.
