Queen snakes, in addition to being the nicest snakes you could ever hope to meet, are a hugely crucial environmental indicator species. Queen snakes rely on streams and rivers with cold, well-oxygenated water and robust crayfish populations; their preferred meal is freshly molted crayfish. This dietary specialization and the species’ sensitivity to water quality make them an important indicator of habitat quality, like a canary in a coal mine.
Many queen snake populations are threatened by declining habitat quality and are becoming increasingly difficult to monitor as these elusive animals become scarcer. To help increase the sensitivity of our ability to monitor queen snakes, we are developing environmental DNA (eDNA) detection methods. This tool utilizes a sensitive and species-specific molecular technique called quantitative PCR (qPCR) to detect queen snake DNA in the pool of free DNA extracted from river water samples.
The search for queen snake eDNA presents particular challenges due to the unique biology of the species. First, as small reptiles, queen snakes shed relatively little DNA compared to other species. Secondly, queen snakes spend time both in river water and on the banks adjacent to rivers, so the relatively small amount of DNA they shed is not all deposited in the water. Finally, because the water bodies queen snakes live in are moving water, the search for queen snake eDNA is quite literally a search for a moving target. This means that we have to be particularly careful and creative as we work to develop a tool that is sensitive enough to detect small amounts of transient queen snake eDNA.
