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The patterns of recovery from injury or infection are not well studied in free-ranging animals. Bats that survive the fungal disease white-nose syndrome (WNS) often emerge from hibernation suffering from skin infections and wing damage. The extent of wing damage reflects physiological and immunological responses to WNS and may impact the ability of bats to fly, forage, and reproduce. Here, we built on previous studies of wing damage in both captive and free-ranging bats to better understand the patterns and extent of wing damage healing in little brown bats (Myotis lucifugus) post-hibernation. We quantified two main types of wing damage, black necrotic dots and white spots, and used the extent of damage to assign bats 1 of 6 wing damage scores. We found that the patterns of black dots and white spots on wing membranes of free-ranging bats aligned with the patterns observed in captive bats soon after emergence from hibernation. Black dot extent was highest at the beginning of the active season in May, while white spot extent peaked 3–4 weeks later. Our study also extends our knowledge of wing damage healing throughout the active season. Wing scores of bats recaptured within the summer decreased or stayed the same and >95% had negligible signs of wing damage by August. We found that black dots were more indicative of disease status than other types of wing damage and could be consistently quantified in the field and from photographs by multiple observers. These results suggest that black dots and our wing damage scoring system can be used to better understand the patterns of post-hibernation healing in little brown bats impacted by WNS. [ABSTRACT FROM AUTHOR]

Pseudogymnoascus destructans is an ascomycetous fungus responsible for the disease dubbed white-nose syndrome (WNS) and massive mortalities of cave-dwelling bats. The fungus infects bat epidermal tissue, causing damage to integumentary cells and pilosebaceous units. Differences in epidermal lipid composition caused by P. destructans infection could have drastic consequences for a variety of physiological functions, including innate immune efficiency and water retention. While bat surface lipid and stratum corneum lipid composition have been described, the differences in epidermal lipid content between healthy tissue and P. destructans-infected tissue have not been documented. In this study, we analyzed the effect of wing damage from P. destructans infection on the epidermal polar lipid composition (glycerophospholipids [GPs] and sphingomyelin) of little brown bats (Myotis lucifugus). We hypothesized that infection would lead to lower levels of total lipid or higher oxidized lipid product proportions. Polar lipids from three damaged and three healthy wing samples were profiled by electrospray ionization tandem mass spectrometry. We found lower total broad lipid levels in damaged tissue, specifically etherlinked phospholipids, lysophospholipids, phosphatidylcholine, and phosphatidylethanolamine. Thirteen individual GP species from four broad GP classes were present in higher amounts in healthy tissue. Six unsaturated GP species were absent in damaged tissue. Our results confirm that P. destructans infection leads to altered lipid profiles. Clinical signs of WNS may include lower lipid levels and lower proportions of unsaturated lipids due to cellular and glandular damage. [ABSTRACT FROM AUTHOR]

Infection of North American bats with the keratin-digesting fungus Geomyces destructans often results in holes and ruptures of wing membranes, yet it is unknown whether flight performance and metabolism of bats are altered by such injuries. I conducted flight experiments in a circular flight arena with Myotis albescens and M. nigricans individuals with an intact or ruptured trailing edge of one of the plagiopatagial membranes. In both species, individuals with damaged wings were lighter, had a higher aspect ratio (squared wing span divided by wing area) and an increased wing loading (weight divided by wing area) than conspecifics with intact wings. Bats with an asymmetric reduction of the wing area flew at similar speeds to conspecifics with intact wings but performed fewer flight manoeuvres. Individuals with damaged wings showed lower metabolic rates during flight than conspecifics with intact wings, even when controlling for body mass differences; the difference in mass-specific metabolic rate may be attributable to the lower number of flight manoeuvres (U-turns) by bats with damaged wings compared with conspecifics with intact wings. Possibly, bats compensated for an asymmetric reduction in wing area by lowering their body mass and avoiding flight manoeuvres. In conclusion, it may be that bats suffer from moderate wing damage not directly, by experiencing increased metabolic rate, but indirectly, by a reduced manoeuvrability and foraging success. This could impede a bat's ability to gain sufficient body mass before hibernation. [ABSTRACT FROM AUTHOR]