Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, 10315 Berlin, Germany.
J Exp Biol. 2013 Apr 15;216(Pt 8):1516-21. doi: 10.1242/jeb.079509. Epub 2013 Jan 24.
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.
北美蝙蝠感染角蛋白消化真菌 Geomyces destructans 后，翅膀膜常出现穿孔和破裂，但目前尚不清楚此类损伤是否会改变蝙蝠的飞行性能和新陈代谢。我用 Myotis albescens 和 M. nigricans 个体在一个圆形飞行竞技场进行了飞行实验，这些个体的一个翼膜的后缘有完整或破裂。在这两个物种中，翅膀受损的个体比具有完整翅膀的个体更轻，展弦比（翼展的平方除以翼面积）更高，翼载荷（体重除以翼面积）更大。与具有完整翅膀的同类相比，翅膀面积不对称减少的蝙蝠飞行速度相似，但飞行动作较少。与具有完整翅膀的同类相比，翅膀受损的个体在飞行过程中表现出较低的代谢率，即使控制了体重差异；与具有完整翅膀的同类相比，翅膀受损的个体飞行动作（U 型转弯）较少，这可能导致质量特异性代谢率的差异。可能是蝙蝠通过降低体重和避免飞行动作来补偿翅膀面积的不对称减少。总之，蝙蝠可能会因中度的翅膀损伤而间接（通过降低机动性和觅食成功率）而不是直接（通过增加代谢率）遭受影响。这可能会妨碍蝙蝠在冬眠前获得足够体重的能力。
