Seasonal and reproductive effects on wound healing in the flight membranes of captive big brown bats

Abstract

The flight membranes of bats serve a number of physiological functions important for survival. Although flight membrane injuries are commonly observed in wild-caught bats, in most cases the damage heals completely. Previous studies examining wound healing in the flight membranes of bats have not taken into consideration energy constraints that could influence healing times. Wound healing results in increased energy demands, therefore we hypothesized that wound healing times would be slower during periods of energy conservation and/or energy output. In this study we used an 8 mm diameter circular punch tool to biopsy the wing membranes of healthy adult female big brown bats (Eptesicus fuscus) from a captive research colony to test the hypothesis that healing times will vary with seasonal temperature changes between the summer and winter seasons, and with reproductive condition between lactating and non-reproductive females. As expected, membrane biopsies took significantly longer to heal during the winter when bats were hibernating compared to the summer when bats were active. Surprisingly, no difference in healing time was observed between lactating and non-reproductive females. The wings of most bats fully healed, although some individuals showed wound expansion demonstrating that impaired healing is occasionally observed in otherwise healthy subjects.

Disease recovery in bats affected by white-nose syndrome

“…Consistent with our predictions based on field data (Fuller et al, 2011), captive bats in our study recovered to a normal state quickly after hibernation, and most signs of disease, except wing damage, were gone within 2 weeks. Skin structure and body condition recovered over a time scale after hibernation consistent with other studies of healing from WNS or other injuries in free-ranging and captive bats (Faure et al, 2009;Weaver et al, 2009;Fuller et al, 2011;Meteyer et al, 2011;Ceballos-Vasquez et al, 2015;Pollock et al, 2015;Greville et al, 2018;Khayat et al, 2019;Davis and Doster, 1972). Following pathogen clearance, tissue damage caused by both the pathogen and inflammatory reactions (Meteyer et al, 2011(Meteyer et al, , 2012 started to heal, and within 30 days of the start of our study, tissue damage was almost undetectable.…”

An alternative minimally invasive technique for genetic sampling of bats: Wing swabs yield species identification

“…There is growing interest in genetic confirmation of bat species in North America, necessitating a minimally invasive method of obtaining genetic material. When bats enter into hibernation, a period of immune compromise (Weaver et al ), and slowed body maintenance and repair occurs, so that wound‐healing from tissue biopsies is significantly delayed (Worthington‐Wilmer and Barratt , Andrews , Ceballos‐Vasquez et al ). Our results indicate that simple swabbing of bat wings to collect epithelial cells for DNA analysis can be an effective minimally invasive method for genetic sampling of bats.…”

“…Biopsy samples may be taken from the chiropatagium or uropatagium, and preserved for DNA analysis (Lausen 2005, Faure et al 2009). Wounds resulting from biopsies vary in healing time, which may depend largely on the time of year, with wounds made just prior to hibernation taking significantly longer to heal (Faure et al 2009, Weaver et al 2009, Ceballos-Vasquez et al 2014.…”

Wound healing in wild male baboons: Estimating healing time from wound size

“…Wound healing is costly in terms of energy [ 13 – 15 ]. Logically, a longer healing time is associated with a higher risk of infection or suppuration, and higher energy loss to the healing process.…”