Helena Jahelková

Increasing Incidence of Geomyces destructans Fungus in Bats from the Czech Republic and Slovakia

Background White-nose syndrome is a disease of hibernating insectivorous bats associated with the fungus Geomyces destructans. It first appeared in North America in 2006, where over a million bats died since then. In Europe, G. destructans was first identified in France in 2009. Its distribution, infection dynamics, and effects on hibernating bats in Europe are largely unknown. Methodology/Principal Findings We screened hibernacula in the Czech Republic and Slovakia for the presence of the fungus during the winter seasons of 2008/2009 and 2009/2010. In winter 2009/2010, we found infected bats in 76 out of 98 surveyed sites, in which the majority had been previously negative. A photographic record of over 6000 hibernating bats, taken since 1994, revealed bats with fungal growths since 1995; however, the incidence of such bats increased in Myotis myotis from 2% in 2007 to 14% by 2010. Microscopic, cultivation and molecular genetic evaluations confirmed the identity of the recently sampled fungus as G. destructans, and demonstrated its continuous distribution in the studied area. At the end of the hibernation season we recorded pathologic changes in the skin of the affected bats, from which the fungus was isolated. We registered no mass mortality caused by the fungus, and the recorded population decline in the last two years of the most affected species, M. myotis, is within the population trend prediction interval. Conclusions/Significance G. destructans was found to be widespread in the Czech Republic and Slovakia, with an epizootic incidence in bats during the most recent years. Further development of the situation urgently requires a detailed pan-European monitoring scheme.

Testing hypotheses of bat baculum function with 3D models derived from microCT

The baculum (os penis) has been extensively studied as a taxon‐specific character in bats and other mammals but its mechanical function is still unclear. There is a wide consensus in the literature that the baculum is probably a sexually selected character. Using a novel approach combining postmortem manipulation and three‐dimensional (3D) imaging, we tested two functional hypotheses in the common noctule bat Nyctalus noctula, the common pipistrelle Pipistrellus pipistrellus, and Nathusius’ pipistrelle Pipistrellus nathusii: (i) whether the baculum can protect the distal urethra and urethral opening from compression during erection and copulation; and (ii) whether the baculum and corpora cavernosa form a functional unit to support both the penile shaft and the more distal glans tip. In freshly dead or frozen and thawed bats, we compared flaccid penises with artificially ‘erect’ penises that were inflated with 10% formalin. Penises were stained with alcoholic iodine and imaged with a lab‐based high‐resolution x‐ray microtomography system. Analysis of the 3D images enabled us to compare the changes in relative positions of the baculum, corpora cavernosa, urethra, and corpus spongiosum with one another between flaccid and ‘erect’ penises. Our results support both functional hypotheses, indicating that the baculum probably performs two different roles during erection. Our approach should prove valuable for comparing and testing the functions of different baculum morphologies in bats and other mammals. Moreover, we have validated an essential component of the groundwork necessary to extend this approach with finite element analysis for quantitative 3D biomechanical modeling of penis function.

Mating system of a migratory bat, Nathusius' pipistrelle (Pipistrellus nathusii): different male strategies*

The mating system of European bats is often reported as ‘resource-defence polygyny’ where the resource is a male roost and its adjacent territory. With a large amount of field data we tested predictions of that model on the spatial dispersal of males in a resident population of a migratory species, Pipistrellus nathusii, well known for its complex vocal advertising by males during the mating season. The study was conducted in southern Bohemia throughout nine seasons (1999–2007) and revealed that (i) pronounced aggregations of male roosts and vocalization sites were affected by the vicinity of the breeding colony, and (ii) dyadic or triadic aggregations were observed in 65% of resident males that shared a common vocalization site. Dyadic or triadic groups were often quite stable over time (for up to seven successive years). No direct agonistic behaviour was observed between group members in contrast to regularly observed synchronization in their activity patterns and advertisement vocalizations. The busy vocalization sites were also visited by alien males that also produced advertisement vocalization and by non-vocalizing males that may have acted as sneaks. All these phenomena suggest considerable diversity in male strategies, suggesting that the mating system does not correspond entirely to ‘resource-defence polygyny’ nor can it be regarded as a lek mating system to which it corresponds in other characteristics (e.g., aggregations of males and the essential role of female choice). We expect that the broad diversity in mating tactics that characterises the species under study may also reveal features relevant to the mating systems of other temperate bats.

History of the Pipistrellus pipistrellus group in Central Europe in light of its fossil record

ABSTRACT In contrast to proposed paleobiogeographic scenarios based on molecular data, the fossil record suggests that in Central Europe the common pipistrelles, quite rich in the Holocene fossil record, first appeared as late as the present glacial cycle (including the Weichselian interstadials). Bats of this group are completely absent from the rich pre-Weichselian record available from Central Europe but occur in the early Middle Pleistocene record in the Mediterranean (Spain, Malta). Thus, it seems that the European range of common pipistrelles was restricted to the Mediterranean region until their northward spread during the present glacial cycle. The proposed range expansion (supposedly from multiple sources) is explained by climatic specificities of the present glacial cycle, namely with repeated extension of the semiarid, warm open-ground habitats that began in the Mediterranean region by the end of the Eemian.