Bat white-nose disease fungus diversity in time and space.

White-nose disease (WND), caused by the psychrophilic fungus Pseudogymnoascusdestructans, represents one of the greatest threats for North American hibernating bats. Research on molecular data has significantly advanced our knowledge of various aspects of the disease, yet more studies are needed regarding patterns of P.destructans genetic diversity distribution. In the present study, we investigate three sites within the native range of the fungus in detail: two natural hibernacula (karst caves) in Bulgaria, south-eastern Europe and one artificial hibernaculum (disused cellar) in Germany, northern Europe, where we conducted intensive surveys between 2014 and 2019. Using 18 microsatellite and two mating type markers, we describe how P.destructans genetic diversity is distributed between and within sites, the latter including differentiation across years and seasons of sampling; across sampling locations within the site; and between bats and hibernaculum walls. We found significant genetic differentiation between hibernacula, but we could not detect any significant differentiation within hibernacula, based on the variables examined. This indicates that most of the pathogen's movement occurs within sites. Genotypic richness of P.destructans varied between sites within the same order of magnitude, being approximately two times higher in the natural caves (Bulgaria) compared to the disused cellar (Germany). Within all sites, the pathogen's genotypic richness was higher in samples collected from hibernaculum walls than in samples collected from bats, which corresponds with the hypothesis that hibernacula walls represent the environmental reservoir of the fungus. Multiple pathogen genotypes were commonly isolated from a single bat (i.e. from the same swab sample) in all study sites, which might be important to consider when studying disease progression.

Conservative pattern of interaction of bat and human IgG antibodies with FcRn.

Recently, numerous studies report bats as reservoirs of emerging pathogens with little to no signs of infections. This is thought to be connected to the unique immune system of bats, which remains poorly characterized. Despite the physiological importance of the Neonatal Fc receptor (FcRn) in the homeostasis of IgG antibodies, it is unclear how its functional activity is evolutionary conservative among mammals, and so is the case for bats. Using surface plasmon resonance-based technology, we tested the interactions of IgG antibodies isolated from three bat species with recombinant human and mouse FcRn. Our data show that IgG from the studied bat species binds to both human and mouse FcRn, albeit with distinct affinities. Importantly, the binding pattern of bat IgG is similar to human IgG. This confirms the conservative nature of IgG-FcRn interaction and highlights the importance of FcRn IgG salvaging system in bats.

First record of Psorergatoides Fain, 1959 (Acari, Cheyletoidea, Psorergatidae) for the Balkan Peninsula with description of the cutaneous lesions on the wing membrane of its hosts Myotismyotis (Borkhausen, 1797) and Myotisblythii (Tomes, 1857) (Chiroptera, Vespertilionidae).

Healthy wing membranes are essential for bats. They are critical for maintaining the water balance and, during hibernation, they protect the bat's body from dehydration. Assessing the state of the membrane visually is an easy and effective way to monitor a bat's health and discover abnormal structures and infections in wild bat populations. During pre- and post-hibernation surveys of bats' wings, we identified the presence of skin mites, Psorergatoideskerivoulae (Fain, 1959). The parasite causes cutaneous lesions on the wing membranes of the greater moused-eared bat, Myotismyotis (Borkhausen, 1797) and the lesser moused-eared bat, Myotisblythii (Tomes, 1857). The lesser mouse-eared bat is a new host for this parasite. Our study is the first to describe the histopathology of the infection on the wings of the greater and lesser mouse-eared bats. To our knowledge, this is the southernmost record of this parasite and the first mention of the genus Psorergatoides for the Balkans.

DNA metabarcoding and spatial modelling link diet diversification with distribution homogeneity in European bats.

Inferences of the interactions between species' ecological niches and spatial distribution have been historically based on simple metrics such as low-resolution dietary breadth and range size, which might have impeded the identification of meaningful links between niche features and spatial patterns. We analysed the relationship between dietary niche breadth and spatial distribution features of European bats, by combining continent-wide DNA metabarcoding of faecal samples with species distribution modelling. Our results show that while range size is not correlated with dietary features of bats, the homogeneity of the spatial distribution of species exhibits a strong correlation with dietary breadth. We also found that dietary breadth is correlated with bats' hunting flexibility. However, these two patterns only stand when the phylogenetic relations between prey are accounted for when measuring dietary breadth. Our results suggest that the capacity to exploit different prey types enables species to thrive in more distinct environments and therefore exhibit more homogeneous distributions within their ranges.

Agriculture shapes the trophic niche of a bat preying on multiple pest arthropods across Europe: Evidence from DNA metabarcoding.

The interaction between agricultural production and wildlife can shape, and even condition, the functioning of both systems. In this study, we i) explored the degree to which a widespread European bat, namely the common bent-wing bat Miniopterus schreibersii, consumes crop-damaging insects at a continental scale, and ii) tested whether its dietary niche is shaped by the extension and type of agricultural fields. We employed a dual-primer DNA metabarcoding approach to characterize arthropod 16S and COI DNA sequences within bat faecal pellets collected across 16 Southern European localities, to first characterize the bat species' dietary niche, second measure the incidence of agricultural pests across their ranges and third assess whether geographical dietary variation responds to climatic, landscape diversity, agriculture type and vegetation productivity factors. We detected 12 arthropod orders, among which lepidopterans were predominant. We identified >200 species, 44 of which are known to cause agricultural damage. Pest species were detected at all but one sampling site and in 94% of the analysed samples. Furthermore, the dietary diversity of M. schreibersii exhibited a negative linear relation with the area of intensive agricultural fields, thus suggesting crops restrict the dietary niche of bats to prey taxa associated with agricultural production within their foraging range. Overall, our results imply that M. schreibersii might be a valuable asset for biological pest suppression in a variety of agricultural productions and highlight the dynamic interplay between wildlife and agricultural systems.