I've watched a few videos featuring Dr. Robert Mason Mason Laboratory - Robert T. Mason and also have his book "The Snake Scientist" The Snake Scientist - Google Books
His research with T.s.parietalis(Red sided Garter Snake) is awesome. After discovering the pheromone that triggers mating in the male red sided garter snake, he also developed a synthetic version. I've wondered for a long time if the synthetic pheromone he developed was the same in let's say T.radix?(or any other garter snake) Would it trigger a mating response in T.radix?
I emailed him tonight to get his ideas on the question. I also asked for a sample of the pheromone to try it out on my boys.
I'll keep you posted about his response.

He's a great video: