Assessment of Nocturnal and Crepuscular Arthropods and Their Influence on Bat Species on the Eastern Highland Rim

Since the introduction of White Nose Syndrome (WNS) in the U.S. in 2007, there have been mass mortalities of bats around North America. WNS is caused by the parasitic and psychrophilic fungus Pseudogymnoascus destructans, which depletes lipid resources of bats. Researchers linked survival of infection of WNS to lipid concentrations of bats. This nutrition associated link has made it critical to understand prey availability as survival of WNS is dependent on food intake. Traditional insect research often overlooks nocturnal arthropods and for multiple seasonal periods. The increase of invasive species and global insect decline has also raised the need for arthropod diversity studies. Our objective was to determine the drivers of insects and how they influence bats. Insects were collected with either (1) ultraviolet traps or (2) CDC light traps. In collaboration with others, bats were monitored by mist netting and acoustic recordings in conjunction to insect sampling (From June 2022- August 2023 at Arnold Air Force Base, TN). Insect abundance was correlated with insect order biomass, insect family richness, and insect family diversity; indicating that higher number of insects were associated with higher prey biomass available to bats and family diversity in the available prey. Family diversity was correlated to insect abundance, but the composition of families was unique to each habitat and seasom. Abundance of six insect orders (Ephmeroptera, Plecoptera, Trichoptera, Coleoptera, Hemiptera, and Lepidoptera) were highly correlated with temporal variables. Habitat and habitat interactions with season influenced Coleoptera numbers. Mist-net models were poor and indicate that other variables may be more important in predicting presence or absence of a bat species. Evening bat calls were positively associated with the edge habitat and hymenopteran abundance. Eastern red bat calls had a positive relationship with edge habitat and negative ones with forested streams and forested wetlands. Gray bat calls were positively associated with total insect abundance and specifically Lepidoptera. These results suggest studies should consider specific insect orders and insect variables to understand bat foraging. These findings provide an ecological base for future studies at Arnold AFB and link arthropod diversity, abundance, and relative biomass to species of bats.