Many bat species are endangered, but their small size, nocturnal nature and ability to fly can make bats difficult to identify and study.
To address these issues, researchers from Northern Arizona University recently developed “Species from Feces,” a new DNA barcoding tool that can identify bat species from their fecal pellets, known as guano.
“Species from Feces is a genetic assay that can take a gob of guano from a bat roost and determine all the species that contributed to the sample, and can do so for bat species from around the world,” says Faith Walker, the Director of Genetics at the Bat Ecology and Genetics Lab in Arizona, and lead author of the study.
The assay identifies bat species based on genetic markers, small DNA segments that vary between species and act as unique “barcodes.” Specifically, Species from Feces uses the mitochondrial gene cytochrome c oxidase (COI1), a genetic marker that is highly specific to individual bat species. The tool successfully identified 54 different bat species during validation tests.
“With global declines in bat populations and emerging diseases such as white-nose syndrome in North America, it is increasingly important to know which species are where, or to verify identification of species that appear similar,” Walker says.
To learn more about this research and its broader potential for impact, I interviewed Walker via email.
What drew you to studying bats?
FW: Because bats are small, nocturnal, fly, can travel great distances nightly or annually, and don’t always roost in groups, they are notoriously difficult to study. Much remains unknown about many aspects of their biology, and yet bats globally are faced with population declines, extinction, and here in North America, White-nose Syndrome. I was drawn to both the scientific challenge and conservation need.
What are some of the challenges that researchers face when trying to identify bat species?
FW: Often the challenge is simply finding bats. One can visit a roost, which might be in a cave, mine, bridge, or building, and not see any bats (but see lots of guano!). Even when bats are captured, some species are morphologically similar to one another and can be difficult to tell apart.
Why did you think bat guano might be useful for identifying bat species?
FW: I have a long history of using non-invasive genetic samples like feces to learn about species, so this was a natural progression. Guano is a godsend because unlike bats it’s stationary and easy to find, and it contains lots of information.
Could the Species from Feces assay be used to identify animals beyond bats?
FW: Species from Feces was crafted to target only bats, but the process can be used for any taxonomic group. The analysis pipeline to develop it can be readily adopted for other applications. For instance, we’re now using a Species from Feces-esque approach to determine the plants that an endangered mouse prefers to eat.
How might non-invasive sampling techniques help classify and conserve animals?
FW: I’m a big proponent of non-invasive genetic sampling, especially for cryptic or endangered wildlife. For difficult-to-study animals like bats, it’s simply more effective. And it’s easier on wildlife in general (although often it’s harder on the scientist!); it doesn’t stress them and doesn’t impact behavior or movements.
What are the next steps for your research?
FW: We’re developing Species from Feces Mobile, so that we can sequence in the field in remote locations around the world, which will be particularly useful for finding critically endangered bats. We’re also seeing how far we can push our Species from Feces assay, i.e., with environmental DNA. This involves sampling water from bat drinking sources like ponds as well as soil from roost areas to determine if we can detect bat species.
Research Article: Walker FM, Williamson CHD, Sanchez DE, Sobek CJ, Chambers CL (2016) Species From Feces: Order-Wide Identification of Chiroptera From Guano and Other Non-Invasive Genetic Samples. PLoS ONE 11(9): e0162342. doi:10.1371/journal.pone.0162342
Image Credit: Faith Walker