This work is part of a study investigating the movement of microcystin from aquatic to terrestrial ecosystems via trophic transfer. Little brown bats (Myotis lucifugus), feeding opportunistically on aquatic insects including Hexagenia mayflies, were collected from a maternity roost near Little Traverse Lake (Leelanau County, Michigan, USA). Bats and fecal samples were collected for dietary analysis, quantification of microcystin in livers and feces, and histopathological evaluation of the liver. Liver was collected in RNAlater and stored frozen. Livers from three bats with the highest microcystin levels by ELISA were thawed, washed with PBS, fixed in 10% neutral buffered formalin, processed routinely for histopathology, and assessed by light microscopy. Microscopic lesions included centrilobular congestion, periportal to midzonal hepatocellular vacuolation, and low numbers of portal inflammatory cells. These changes are non-specific; no evidence of acute microcystin toxicosis was present. Results suggest that despite the detection of microcystin in bat feces from the site, there is no evidence of acute clinical toxicity in the bats collected.

This work is part of an experimental trial investigating the effects of microclimate conditions of temperature and humidity on a fungal pathogen, Pseudogymnoascus destructans (Pd), that causes white-nose syndrome (WNS) disease in hibernating bats. As part of the trial, tri-colored bats (Perimyotis subflavus) were exposed to Pseudogymnoascus destructans (Pd) and allowed to hibernate in chambers with a variety of temperature and humidity conditions. Bats were euthanized after 83 days. A portion of the wing was rolled around dental wax dowels, fixed in 10% neutral buffered formalin, processed and stained with periodic acid-Schiff, and assessed by light microscopy for evidence of fungal infection. Three types of cutaneous infection were described histologically, including characteristic WNS cupping erosions, neutrophilic pustules with fungal hyphae, and fungal hyphae in the stratum corneum with dermal necrosis. Bats with any of these three conditions were scored as WNS-positive by histology. Only 11% (10/95) of bats scored as positive by histology. Of the 10 bats scored as positive, 3 bats had cupping erosions containing fungal hyphae and 7 bats had either neutrophilic pustules containing fungal hyphae, dermal necrosis associated with intra-epidermal fungal hyphae, or both. Overall, lack of infection and disease outcomes in this experiment limited our ability to make robust conclusions about the influence of microclimates on the development of WNS in bats.

This work is part of an experimental trial investigating the effects of microclimate conditions of temperature and humidity on a fungal pathogen, Pseudogymnoascus destructans (Pd), that causes white-nose syndrome (WNS) disease in hibernating bats. As part of the trial, tri-colored bats (Perimyotis subflavus) were exposed to Pseudogymnoascus destructans (Pd) and allowed to hibernate in chambers with a variety of temperature and humidity conditions. Bats were euthanized after 83 days. A portion of the wing was rolled around dental wax dowels, fixed in 10% neutral buffered formalin, processed and stained with periodic acid-Schiff, and assessed by light microscopy for evidence of fungal infection. Three types of cutaneous infection were described histologically, including characteristic WNS cupping erosions, neutrophilic pustules with fungal hyphae, and fungal hyphae in the stratum corneum with dermal necrosis. Bats with any of these three conditions were scored as WNS-positive by histology. Only 11% (10/95) of bats scored as positive by histology. Of the 10 bats scored as positive, 3 bats had cupping erosions containing fungal hyphae and 7 bats had either neutrophilic pustules containing fungal hyphae, dermal necrosis associated with intra-epidermal fungal hyphae, or both. Overall, lack of infection and disease outcomes in this experiment limited our ability to make robust conclusions about the influence of microclimates on the development of WNS in bats.

White-nose syndrome (WNS), a fungal disease that has caused catastrophic population declines of bats in eastern North America, is rapidly spreading across the continent and now threatens previously unexposed bat species in western North America. The causal agent of WNS, Pseudogymnoascus destructans, can infect many species of hibernating bats, but susceptibility to WNS varies by host species. Predicting which western bat species will be most susceptible to WNS would be of great value for establishing conservation priorities. We previously reported that certain traits of the skin microbiome of bat species in eastern North America were strongly associated with tolerance to WNS. Using these traits, we developed a model to predict WNS susceptibility of 13 species of western North American bats. Based on the model, only two bat species, Myotis velifer and Eptesicus fuscus, were predicted to be WNS-tolerant. If accurate, a greater proportion of western bat species will be susceptible to the disease compared to eastern bat species, indicating that WNS may pose a significant conservation threat in western North America.

Little brown bat (Myotis lucifugus) weights and SARS-CoV2 test results were collected as part of study to assess transmission potential of SARS-CoV2 in North American bat populations. It has been proposed that the SARS-CoV-2 virus originated in Asian bats and subsequently spread through human populations as a pandemic. There is concern that infected humans could transmit the virus to native North American bats, therefore the susceptibility of several North American bat species to the pandemic virus has been experimentally assessed. Big brown bats (Eptesicus fuscus) were shown to be resistant to infection by SARS-CoV-2, while Mexican free-tailed bats (Tadarida brasiliensis) became infected and orally excreted moderate amounts of virus for up to 18 days post-inoculation. Little brown bats (Myotis lucifugus) frequently contact humans, and their populations are threatened over much of their range due to white-nose syndrome, a fungal disease that is continuing to spread across North America. For this study, we experimentally challenged little brown bats with SARS-CoV-2 to determine their susceptibility, host potential, and whether the virus presents an additional risk to this species. We present data, including oral and rectal excretion, health status and serological evidence that shows this species was resistant to infection by SARS-CoV-2. These findings will provide reassurance to wildlife rehabilitators, biologists, conservation scientists, and the public at large who are concerned with possible transmission of this virus to threatened bat populations.

North American bats have experienced catastrophic population declines from white-nose syndrome (WNS), a fungal disease caused by Pseudogymnoascus destructans (Pd). Although Pd can infect many hibernating bat species, population-level impacts of WNS vary by host species. Microbial skin assemblages, including the fungal component (mycobiome), can influence host resistance to infectious diseases; however, little is known about the influence the skin mycobiome of bats may have on susceptibility to WNS. We sampled ten bat species in the eastern United States that are known to be either susceptible, tolerant, or resistant to WNS by swabbing their wing skin. We then cultured fungi from the swabs, isolated morphologically distinct colonies of fungi, and identified the fungi through DNA sequencing. Using this culture-based approach, we compared skin mycobiome characteristics. The mycobiomes of WNS-susceptible bat species had significantly lower alpha diversity and abundance compared to WNS-tolerant species. Overall mycobiome structure did not vary based on WNS-susceptibility, but several yeast species were differentially abundant on WNS-tolerant bat species. Multi-locus phylogenies and scanning electron microscopy suggest that some yeasts likely represent novel taxa which may be adapted to colonizing bat skin. Further exploration of interactions between Pd and components of the mycobiome may prove useful for predicting susceptibility of bat populations and for developing effective mitigation strategies for WNS.

Vector datasets of CWHR range maps are one component of California Wildlife Habitat Relationships (CWHR), a comprehensive information system and predictive model for Californias wildlife. The CWHR System was developed to support habitat conservation and management, land use planning, impact assessment, education, and research involving terrestrial vertebrates in California. CWHR contains information on life history, management status, geographic distribution, and habitat relationships for wildlife species known to occur regularly in California. Range maps represent the maximum, current geographic extent of each species within California. They were originally delineated at a scale of 1:5,000,000 by species-level experts and have gradually been revised at a scale of 1:1,000,000. For more information about CWHR, visit the CWHR webpage (https://www.wildlife.ca.gov/Data/CWHR). The webpage provides links to download CWHR data and user documents such as a look up table of available range maps including species code, species name, and range map revision history; a full set of CWHR GIS data; .pdf files of each range map or species life history accounts; and a User Guide.

False positive occupancy analysis predictions with model uncertainty based on summertime data provided to support the three bat species status assessment (SSA) for Myotis lucifigus (MYLU), Myotis septentrionalis (MYSE), and Perimyotis subflavus (PESU). The objectives outlined by the Fish and Wildlife Service’s SSA team were to estimate summertime distributions across the entire species range. Statistical analysis included five types of response data requested from the North American Bat Monitoring Program database (NABat): automatically identified stationary acoustic calls, manually vetted stationary acoustic calls, automatically identified mobile acoustic calls, manually vetted mobile acoustic calls, and capture records. Statistical analysis was for the summertime distribution modeling, data collected between June 1 and Sept 1 during 2010 until 2019 were only included.