Flying or sleeping: flight activity of bats in natural cave with confirmed WNS

Abstract

White-nose Syndrome (WNS) decimates bat populations in North America but similar effects have not been recorded in Europe. WNS-affected bats exhibit abnormal hibernation behaviour that prematurely deplete fat reserves and ultimately causes death by starvation. In the deep hibernation period (December–March) of 2006/07 (pre-WNS) and 2010/11 (post-WNS), we monitored bat hibernation behaviour and flight activity to test the potential impact of WNS on European bats. We registered no abnormal changes in bat hibernation behaviour (movement to visible sites, utilization of dynamic cave sections), flight activity level, its direction or seasonal pattern remained unchanged following WNS infection. Flight activity inside the cave and at its entrance was generally low during the deep hibernation period and temperature remained the best predictor of activity level. In general, stable hibernation behaviour and activity patterns suggests that they are apparently optimized for European winter conditions and support the hypothesis that the fungus has been present in Europe for a long time and has only recently invaded North America.