DNA metabarcoding of Myotis lucifugus guano reveals unexplored arthropod diversity and diet variability in Newfoundland

All bats in Newfoundland, Canada are insectivores. While the dietary insects of several bat species have been investigated elsewhere in Canada and North America, little is known about the insect prey of Newfoundland bats. Here, we use DNA metabarcode sequencing of the mitochondrial cytochrome oxidase subunit 1 (COI) gene to identify insect prey from Myotis lucifugus guano. Among 21 guano samples from six sites in Newfoundland, 346 amplicon sequence variants (ASVs) of arthropods were identified. Among these 346 ASVs, 343 and 330 have not been documented in the barcode of life database from Newfoundland and Canada, respectively. In addition, only 34 and 54 of the 346 ASVs were identified to 19 species and 24 genera, respectively, with high confidence. Overall, Trichoptera had the highest percentage of COI sequences while Coleoptera had the most ASVs. High arthropod variabilities were observed among guano samples from both within and among sites. In eastern Newfoundland, notable difference in prey arthropod compositions was observed between two sampling times. Together, our results show tremendous undiscovered arthropod diversity in Newfoundland and that bat guano DNA metabarcoding can be an effective tool to help reveal this biodiversity. The implications of this research to bat conservation were discussed.