Frequent Arousal from Hibernation Linked to Severity of Infection and Mortality in Bats with White-Nose Syndrome

White-nose syndrome (WNS), an emerging infectious disease that has killed over 5.5 million hibernating bats, is named for the causative agent, a white fungus (Geomyces destructans (Gd)) that invades the skin of torpid bats. During hibernation, arousals to warm (euthermic) body temperatures are normal but deplete fat stores. Temperature-sensitive dataloggers were attached to the backs of 504 free-ranging little brown bats (Myotis lucifugus) in hibernacula located throughout the northeastern USA. Dataloggers were retrieved at the end of the hibernation season and complete profiles of skin temperature data were available from 83 bats, which were categorized as: (1) unaffected, (2) WNS-affected but alive at time of datalogger removal, or (3) WNS-affected but found dead at time of datalogger removal. Histological confirmation of WNS severity (as indexed by degree of fungal infection) as well as confirmation of presence/absence of DNA from Gd by PCR was determined for 26 animals. We demonstrated that WNS-affected bats aroused to euthermic body temperatures more frequently than unaffected bats, likely contributing to subsequent mortality. Within the subset of WNS-affected bats that were found dead at the time of datalogger removal, the number of arousal bouts since datalogger attachment significantly predicted date of death. Additionally, the severity of cutaneous Gd infection correlated with the number of arousal episodes from torpor during hibernation. Thus, increased frequency of arousal from torpor likely contributes to WNS-associated mortality, but the question of how Gd infection induces increased arousals remains unanswered

The Distribution, Status, and Ecology of the Eastern Woodrat (Neotoma Floridana) in Missouri

Woodrats in the eastern United States have experienced a dramatic reduction in range and population numbers in recent years. Because of this, and the fact that the Missouri Department of Conservation has the status of the eastern woodrat, Neotoma floridana, as status undetermined, this study was conducted to collect information on the eastern woodrat in Missouri. A distribution map was developed from two sources: 1) surveys sent to individuals that had knowledge of woodrat occurrence, or 2) manually searching of areas. In addition, the home range and activity patterns of the eastern woodrat were determined on Ruth and Paul Henning Conservation Area in Taney County and on private land in Christian County. Of the areas that contained woodrats (N=159), the dominant habitat types were cave (51.57%), forest with exposed rock (17.61%), and both edge and forest habitats (8.81%). Home ranges were determined using the fluorescent pigment method. The home range of males ranged from 500-8500 m², while females ranged from 1000-3000 m². Remote censusing cameras were used to document the activity patterns of the eastern woodrat. The woodrat was the most common of the 31 species of animals photographed (40.44% of the total pictures). The activity of the woodrat exhibited a peak before midnight with a decrease in activity throughout the rest of the night. Although woodrats are not in immediate need of protection, the regular monitoring of the status of woodrats in Missouri should be implemented because of habitat loss

Intra- and interspecific responses to Rafinesque’s big-eared bat (Corynorhinus rafinesquii) social calls.

Bats respond to the calls of conspecifics as well as to calls of other species; however, few studies have attempted to quantify these responses or understand the functions of these calls. We tested the response of Rafinesque’s big-eared bats (Corynorhinus rafinesquii) to social calls as a possible method to increase capture success and to understand the function of social calls. We also tested if calls of bats within the range of the previously designated subspecies differed, if the responses of Rafinesque’s big-eared bats varied with geographic origin of the calls, and if other species responded to the calls of C. rafinesquii. We recorded calls of Rafinesque’s big-eared bats at two colony roost sites in South Carolina, USA. Calls were recorded while bats were in the roosts and as they exited. Playback sequences for each site were created by copying typical pulses into the playback file. Two mist nets were placed approximately 50–500 m from known roost sites; the net with the playback equipment served as the Experimental net and the one without the equipment served as the Control net. Call structures differed significantly between the Mountain and Coastal Plains populations with calls from the Mountains being of higher frequency and longer duration. Ten of 11 Rafinesque’s big-eared bats were caught in the Control nets and, 13 of 19 bats of other species were captured at Experimental nets even though overall bat activity did not differ significantly between Control and Experimental nets. Our results suggest that Rafinesque’s big-eared bats are not attracted to conspecifics’ calls and that these calls may act as an intraspecific spacing mechanism during foraging

Day-roost tree selection by northern long-eared bats—What do non-roost tree comparisons and one year of data really tell us?

Bat day-roost selection often is described through comparisons of day-roosts with randomly selected, and assumed unused, trees. Relatively few studies, however, look at patterns of multi-year selection or compare day-roosts used across years. We explored day-roost selection using 2 years of roost selection data for female northern long-eared bats (Myotis septentrionalis) on the Fort Knox Military Reservation, Kentucky, USA. We compared characteristics of randomly selected non-roost trees and day-roosts using a multinomial logistic model and day-roost species selection using chi-squared tests. We found that factors differentiating day-roosts from non-roosts and day-roosts between years varied. Day-roosts differed from non-roosts in the first year of data in all measured factors, but only in size and decay stage in the second year. Between years, day-roosts differed in size and canopy position, but not decay stage. Day-roost species selection was non-random and did not differ between years. Although bats used multiple trees, our results suggest that there were additional unused trees that were suitable as roosts at any time. Day-roost selection pattern descriptions will be inadequate if based only on a single year of data, and inferences of roost selection based only on comparisons of roost to non-roosts should be limited

Effects of hierarchical roost removal on northern long-eared bat (Myotis septentrionalis) maternity colonies.

Forest roosting bats use a variety of ephemeral roosts such as snags and declining live trees. Although conservation of summer maternity habitat is considered critical for forest-roosting bats, bat response to roost loss still is poorly understood. To address this, we monitored 3 northern long-eared bat (Myotis septentrionalis) maternity colonies on Fort Knox Military Reservation, Kentucky, USA, before and after targeted roost removal during the dormant season when bats were hibernating in caves. We used 2 treatments: removal of a single highly used (primary) roost and removal of 24% of less used (secondary) roosts, and an un-manipulated control. Neither treatment altered the number of roosts used by individual bats, but secondary roost removal doubled the distances moved between sequentially used roosts. However, overall space use by and location of colonies was similar pre- and post-treatment. Patterns of roost use before and after removal treatments also were similar but bats maintained closer social connections after our treatments. Roost height, diameter at breast height, percent canopy openness, and roost species composition were similar pre- and post-treatment. We detected differences in the distribution of roosts among decay stages and crown classes pre- and post-roost removal, but this may have been a result of temperature differences between treatment years. Our results suggest that loss of a primary roost or ≤ 20% of secondary roosts in the dormant season may not cause northern long-eared bats to abandon roosting areas or substantially alter some roosting behaviors in the following active season when tree-roosts are used. Critically, tolerance limits to roost loss may be dependent upon local forest conditions, and continued research on this topic will be necessary for conservation of the northern long-eared bat across its range

Relatedness within and among Myotis septentrionalis colonies at a local scale

We assessed parentage within and among maternity colonies of northern long-eared bats (Myotis septentrionalis Troessart 1897) in north-central Kentucky from 2011â 2013 to examine colony social structure, formation, and membership dynamics. We intensively sampled colonies in close and remote (> 10 km) proximity before and after targeted day-roost removal. Colonies were not necessarily comprised of closely related individuals, although natal philopatry was common. Adjacent colonies often contained maternally-related individuals, indicating that some pups did disperse, albeit not far from their natal home-range. Whereas some young had been sired by males also collected on site, most had not, as would be expected since the species mates in fall near hibernacula across a wider landscape. The number of parentages that we inferred among colonies, however, suggests that outside the maternity season, social groups may be relatively flexible and open. Analysis of microsatellite DNA data showed a low FST (= 0.011) and best fit to a model of one multilocus genotypic cluster across the study area. We observed high turnover in colony membership between years in all colonies, regardless of roost removal treatment. Our results suggest that female northern long-eared bats exhibit fidelity to a general geographic area and complex, dynamic social-genetic structure.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Summary of female northern long-eared bat roost characteristics.

<p>Summary of roost characteristics (mean ± SD) for 3 northern long-eared bat (<i>Myotis septentrionalis</i>) maternity colonies subjected to different levels of roost removal on the Fort Knox military reservation, Kentucky, USA, pre- and post- roost removal (2011 and 2012) treatment. Significant differences (<i>P</i> < 0.05) between groups are indicated by superscripts a-e.</p><p>Summary of female northern long-eared bat roost characteristics.</p