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We document white‐nose syndrome (WNS), a lethal disease of bats caused by the fungus Pseudogymnoascus destructans (Pd), and hibernacula microclimate in New Brunswick, Canada. Our study area represents a more northern region than is common for hibernacula microclimate investigations, providing insight as to how WNS may impact bats at higher latitudes. To determine the impact of the March 2011 arrival of Pd in New Brunswick and the role of hibernacula microclimate on overwintering bat mortality, we surveyed bat numbers at hibernacula twice a year from 2009 to 2015. We also collected data from iButton temperature loggers deployed at all sites and data from HOBO temperature and humidity loggers at three sites. Bat species found in New Brunswick hibernacula include Myotis lucifugus (Little Brown Bat) and M. septentrionalis (Northern Long‐eared Bat), with small numbers of Perimyotis subflavus (Tricolored Bat). All known hibernacula in the province were Pd‐positive with WNS‐positive bats by winter 2013. A 99% decrease in the overwintering bat population in New Brunswick was observed between 2011 and 2015. We did not observe P. subflavus during surveys 2013–2015 and the species appears to be extirpated from these sites. Bats did not appear to choose hibernacula based on winter temperatures, but dark zone (zone where no light penetrates) winter temperatures did not differ among our study sites. Winter dark zone temperatures were warmer and less variable than entrance or above ground temperatures. We observed visible Pd growth on hibernating bats in New Brunswick during early winter surveys (November), even though hibernacula temperatures were colder than optimum for in vitro Pd growth. This suggests that cold hibernacula temperatures encountered near the apparent northern range limit for Pd do not sufficiently slow fungal growth to prevent the onset of WNS and associated bat mortality over the winter. [ABSTRACT FROM AUTHOR]

Skin is a key aspect of the immune system in the defence against pathogens. Skin pH regulates the activity of enzymes produced both by hosts and by microbes on host skin, thus implicating pH in disease susceptibility. Skin pH varies inter- and intra-specifically and is influenced by a variety of intrinsic and extrinsic variables. Increased skin alkalinity is associated with a predisposition to cutaneous infections in humans and dogs, and inter-specific and inter-individual variation in skin pH is implicated in differential susceptibility to some skin diseases. The cutaneous pH of bats has not been characterized but is postulated to play a role in susceptibility to white-nose syndrome (WNS), a fungal infection that has decimated several Nearctic bat species. We used non-invasive probes to measure the pH of bat flight membranes in five species with differing susceptibility to WNS. Skin pH ranged from 4.67 to 8.59 and varied among bat species, geographic locations, body parts, age classes, sexes and seasons. Wild Eptesicus fuscus were consistently more acidic than wild Myotis lucifugus, Myotis leibii and Perimyotis subflavus. Juvenile bats had more acidic skin than adults during maternity season but did not differ during swarming. Male M. lucifugus were more acidic than females during maternity season, yet this trend reversed during swarming. Bat skin was more acidic in summer compared to winter, a pattern also reported in humans. Skin pH was more acidic in captive than wild E. fuscus , suggesting environmental impacts on skin pH. The pH of roosting substrates affects skin pH in captive bats and may partially explain seasonal patterns in wild bats that use different roost types across seasons. Future research on the influence of pH on microbial pathogenic factors and skin barrier function may provide valuable insights on new therapeutic targets for treating bat skin conditions. [ABSTRACT FROM AUTHOR]

The emergence of the fungal disease white-nose syndrome (WNS) among hibernating bats in North America and its causative pathogen, Geomyces destructans, underscores how little is known about fungi associated with bats and their subterranean environments. Investigating 8 caves and mines in New Brunswick, Canada, we cultured a diverse array of fungi from the fur and skin of apparently healthy, hibernating Myotis lucifugus (Little Brown Bat) and M. septentrionalis (Northern Long-eared Bat) in the year prior to the emergence of WNS in the province. Among the 117 isolated fungal taxa, we found an array of psychrophilic, psychrotrophic, keratinolytic, coprophilous, and saprobic fungi. The most common taxa were Geomycespannorum sensu lato, Penicillium spp., Mortierella spp., Mucor spp., Cephalotrichum stemonitis, Leuconeurospora spp., Penicillium solitum, Cladosporium spp., and Trichosporon dulcitum. Each bat hosted 6.9 ± 3 (SD) fungal taxa, and 30.8 ± 5 taxa were isolated per hibernaculum. Number bftaxa isolated per bat was positively correlated with mean and minimum winter temperatures in the dark zones of hibernacula. Forty-seven of the taxa have never been reported in caves, and an additional 31 taxa are new records for North American caves. The presence of Geomyces pannorum sensu lato on 70% of hibernating bats may complicate results of diagnostic techniques used for identifying G. destructans. Bats hibernating in eastern Canada harbor a rich reservoir of fungal species and probably play a role in moving fungal spores into and between hibernacula, as well as onto the landscape. [ABSTRACT FROM AUTHOR]

Information on bat populations and hibernacula is important for understanding the impacts of white-nose syndrome (WNS), a fatal fungal disease of bats. Estimates of bat populations prior to the outbreak of white-nose syndrome are presented for 2009-2011 for the most significant bat hibernacula known in New Brunswick. At one of these sites we recorded a major mortality event from white-nose syndrome, the first in the Maritime provinces, late in the winter of 2011. Winter surveys of hibernating bats suggest that a minimum of 7 000 bats overwintered in these hibernacula prior to the outbreak of white-nose syndrome in New Brunswick. The majority of hibernating bats in New Brunswick caves are Myotis lucifugus (Little Brown Myotis) and M. septentrionalis (Northern Myotis), with low numbers of Perimyotis subflavus (Tricolored Bat). The New Brunswick hibernacula that support the greatest numbers of overwintering bats have little temperature variation, winter dark zone temperatures averaging 4--5°C, and minimum dark zone temperatures dropping to no lower than 3.1°C. New Brunswick caves with these temperature patterns characteristically have >140 m of main passage and lack both running water and multiple entrances. Few cave sites in the province meet these criteria, and the known winter bat population appears to be smaller than the summer population. Many bats present during the summer in New Brunswick either hibernate in unknown locations in the province or migrate out of the province to locate suitable hibernacula. Such movements may have hastened the arrival of white-nose syndrome in New Brunswick. [ABSTRACT FROM AUTHOR]

Across their range, Raccoons (Procyon lotor) will opportunistically exploit bats (Chiroptera) roosting in caves as a source of food. During a significant mortality event associated with white-nose syndrome (WNS) at a cave in eastern Canada, we estimate that Raccoons consumed 3 169-3827 dead and dying Little Brown Bats (Myotis lucifugus) and Northern Long-eared Bats (M. septentrionalis) infected with white-nose syndrome, equivalent to 62.0-74.9% of the total bat mortality at this site. However, the generally small dispersal distances of Raccoons and their reduced activity during the period when bats are hibernating suggest that Raccoons are likely not a significant vector for moving the fungus associated with white-nose syndrome, Geoniyces destructans, between most caves at this latitude. Nevertheless, since we show that significant numbers of bats can be consumed in hibernacula through opportunistic feeding by Raccoons, estimates of in-cave mortality due to white-nose syndronie should incorporate any evidence of consumption of bats by Raccoons and other predators. [ABSTRACT FROM AUTHOR]

Wildlife are exposed to neurotoxic mercury at locations distant from anthropogenic emission sources because of long-range atmospheric transport of this metal. In this study, mercury bioaccumulation in insectivorous bat species (Mammalia: Chiroptera) was investigated on a broad geographic scale in Canada. Fur was analyzed (n = 1178) for total mercury from 43 locations spanning 20° latitude and 77° longitude. Total mercury and methylmercury concentrations in fur were positively correlated with concentrations in internal tissues (brain, liver, kidney) for a small subset (n = 21) of little brown bats ( Myotis lucifugus ) and big brown bats ( Eptesicus fuscus ), validating the use of fur to indicate internal mercury exposure. Brain methylmercury concentrations were approximately 10% of total mercury concentrations in fur. Three bat species were mainly collected (little brown bats, big brown bats, and northern long-eared bats [ M. septentrionalis ]), with little brown bats having lower total mercury concentrations in their fur than the other two species at sites where both species were sampled. On average, juvenile bats had lower total mercury concentrations than adults but no differences were found between males and females of a species. Combining our dataset with previously published data for eastern Canada, median total mercury concentrations in fur of little brown bats ranged from 0.88–12.78 μg/g among 11 provinces and territories. Highest concentrations were found in eastern Canada where bats are most endangered from introduced disease. Model estimates of atmospheric mercury deposition indicated that eastern Canada was exposed to greater mercury deposition than central and western sites. Further, mean total mercury concentrations in fur of adult little brown bats were positively correlated with site-specific estimates of atmospheric mercury deposition. This study provides the largest geographic coverage of mercury measurements in bats to date and indicates that atmospheric mercury deposition is important in determining spatial patterns of mercury accumulation in a mammalian species. [ABSTRACT FROM AUTHOR]