Characterizing wing tears in common pipistrelles (Pipistrellus pipistrellus): investigating tear distribution, wing strength, and possible causes

Abstract

Bats have large, thin wings that are particularly susceptible to tearing. Anatomical specializations, such as fiber reinforcement, strengthen the wing and increase its resistance to puncture, and an extensive vasculature system across the wing also promotes healing. We investigated whether tear positioning is associated with anatomy in common pipistrelles (Pipistrellus pipistrellus). Wing anatomy was described using histological techniques, imaging, and material testing. Tear information, including type, position, time in rehabilitation, and possible causes, was collected from rehabilitators of injured bats across the United Kingdom. Results suggest that the position of the plagiopatagium (the most proximal wing section to the body), rather than its anatomy, influenced the number, location, and orientation of wing tears. While material testing did not identify the plagiopatagium as being significantly weaker than the chiropatagium (the more distal sections of the wing), the plagiopatagium tended to have the most tears. The position of the tears, close to the body and toward the trailing edge, suggests that they are caused by predator attacks, such as from a cat (Felis catus), rather than collisions. Consistent with this, 38% of P. pipistrellus individuals had confirmed wing tears caused by cats, with an additional 38% identified by rehabilitators as due to suspected cat attacks. The plagiopatagium had the lowest number of blood vessels and highest amounts of elastin fibers, suggesting that healing may take longer in this section. Further investigations into the causes of tears, and their effect on flight capabilities, will help to improve bat rehabilitation.

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.…”

Frequent or scarce? Damage to flight–enabling body parts in bats (Chiroptera)

“…In Central Europe, the predators hunting for bats are owls: tawny owl Strix aluco [62, 63], barn owl Tyto alba [64], and less frequently diurnal predatory birds Corvidae and Paridae [65–68]. Damage to the wing membranes and wings may also be caused by rodent predation [69], by another bat’s attack ([70, 71], own observations), by domestic cats [72, 73] or martes [74].…”

Patterns of post-hibernation wing damage healing in little brown bats (Myotis lucifugus) impacted by white-nose syndrome

“…Very early damage, however, was rarely observed after mid-May. Wings can also be damaged by other nonmetabolic or nondisease causes (Davis 1968;Khayat et al 2019). We noted apparent wing damage that was not related to WNS, such as that caused by parasites, predators, or other environmental hazards (Supplementary Data SD2), but did not include it when determining the final wing score.…”