European Bat Species Research Articles

Automated long‐term monitoring of RFID‐tagged individuals reveals high hibernaculum site fidelity in Daubenton's bats and Natterer's bats

AbstractIn the temperate zone, many bat species depend on underground sites during the autumn mating period and as hibernacula in winter. Anthropogenic or natural alteration or destruction of a hibernaculum may severely threaten the bats that rely on the site, especially if they are not aware of suitable alternatives. Currently, the rate at which bats visit other hibernacula, or disperse between them, is poorly understood. Here, we studied hibernation site fidelity in two European bat species, Daubenton's bat (Myotis daubentonii) and Natterer's bat (Myotis nattereri), that share hibernacula but differ in their hibernation phenology and mating systems. The activity of over 2500 RFID‐tagged individuals was monitored using an automated recording system at the entrances of three hibernacula over eight full years. Hibernation site fidelity was high in both species, with only 1.6% of Daubenton's bats and 4.1% of Natterer's bats moving between the monitored sites during their lifetimes. Juvenile bats moved more frequently than adults and contrary to our expectations, in Natterer's bats, more females moved between hibernacula than males. Movements almost always occurred during the autumn mating season, and more frequently between neighboring hibernacula than between distant sites. Finally, we also found that individuals rarely explored more than one of the three entrances to a site, despite their close proximity. Taken together, our results suggest that some juvenile bats may explore multiple sites, but that they rarely disperse to other hibernacula as adults. As a result, most individuals are either not aware of alternative sites or do not regularly update this information. We therefore argue that the creation of new underground objects as a mitigation measure may not function as an immediate compensation for the disturbance or the loss of an existing hibernaculum. Instead, the proactive identification and protection of existing hibernacula should be prioritized.

Amino acid fund of blood serum of European migrating species of Chiroptera: <i>Vespertilio murinus</i> (Linnaeus, 1758) and <i>Pipistrellus nathusii</i> (Keyserling et blasius, 1839) of the Ural fauna

The amino acid pool of free amino acids in the blood serum of two European migratory bat species: V. murinus and P. nathusii living in the Urals was studied. Statistically significant differences were noted in the formation of the main metabolic groups of free amino acids in yearlings of migratory species: GGAA, NEAA, EAA, SAA (p 0.05). In yearlings of the P. nathusii: GGAA predominates – 79.7% and EAA – 49.4%, and in the yearlings of the V. murinus: GGAA predominates – 74.9% and NEAA – 58.4%. Comparative analysis showed no differences between V. murinus and P. nathusii in the percentage of AAA and BCAA (p 0.05). Statistically significant differences were noted in the formation of metabolic groups of amino acids in the blood of yearlings of migratory species of bats and the resident species of pond bat (p 0.05).

Blood Serum Amino Acid Pool of European Migratory Chiroptera Vespertilio murinus Linnaeus, 1758 and Pipistrellus nathusii Keyserling et Blasius, 1839 of the Ural Fauna.

The pool of free amino acids (AAs) in the blood serum was studied in two European migratory bat species, Vespertilio murinus and Pipistrellus nathusii, of the Urals. Bats from this year's bloods were examined, and significant differences were observed in main metabolic groups of free AAs, including glycogenic (GGAAs), nonessential (NEAAs), essential (EAAs), and sulfur-containing (SCAAs) AAs (p < 0.05). Based on the percent content of the metabolic groups in the total AA pool, GGAAs (79.7%) and EAAs (49.4%) were found to predominate in P. nathusii, and GGAAs (74.9%) and NEAAs (58.4%), in V. murinus. No difference in AAA and BCAA contents was observed between V. murinus and P. nathusii (p > 0.05). The migratory species were shown to significantly differ in the metabolic groups of serum AAs from the resident species Myotis dasycneme (p < 0.05).

Using mobile device built-in microphones to monitor bats: a new opportunity for large-scale participatory science initiatives

Citizen science has become a crucial tool in biodiversity monitoring, often facilitated by the diffusion of mobile devices, such as smartphones and tablets. High costs of professional equipment often limit large-scale monitoring, particularly in bat monitoring programmes based on acoustic surveys. Here we present the potential of using mobile devices for bat monitoring, allowing for large-scale, volunteer-based monitoring programmes. We initially compared mobile devices’ performance with a professional bat detector for recording low-frequency bat calls. We then conducted a citizen science pilot study to test the method’s feasibility in a real-world setting, recording echolocation and social calls of nine European bat species. We found high similarity in spectrogram quality (0.74 ± 0.09 for Samsung, 0.90 ± 0.01 for Huawei, 0.86 ± 0.09 for Xiaomi, 0.69 ± 0.09 for Apple) and average peak frequency (differences of 0.2 ± 0.5 kHz for Samsung, 0.1 ± 0.7 kHz for Huawei, 0.5 ± 1.0 kHz for Xiaomi, 0.1 ± 0.8 kHz for Apple) between calls recorded by mobile devices and professional bat detectors. The number of recorded bat calls per sampling session was also similar. However, differences in sound quality and effectiveness among mobile device brands were found. iOS devices outperformed professional detectors at recording bat calls at increasing distances. The citizen science pilot study tested 35 mobile device models, all of which effectively recorded bats. This study suggests that mobile devices could be an accessible, no-cost tool for large-scale bat monitoring. Incorporating mobile devices into existing monitoring networks or creating new dedicated programmes could not only enhance data collection, but also boost public knowledge and awareness about bats, ultimately promoting informed decision-making and better conservation strategies.

Presence of Alphacoronavirus in Tree- and Crevice-Dwelling Bats from Portugal.

Coronaviruses (CoVs) are RNA viruses capable of infecting a wide range of hosts, including mammals and birds, and have caused significant epidemics such as the ongoing COVID-19 pandemic. Bats, the second most diverse mammalian order, are hosts for various CoVs due to their unique immune responses and ecological traits. This study investigates CoV prevalence in crevice- and tree-dwelling bats in Portugal, a country with limited prior research on bat CoVs. Using nested RT-PCR and sequencing, we screened 87 stool samples from bats, identifying one sample (1.15%) that was positive for Alphacoronavirus, belonging to Pipistrellus pipistrellus. Phylogenetic analysis revealed close genetic relationships with Alphacoronavirus strains from the same bat species in Europe. The low prevalence suggests habitat-specific differences in viral transmission, with cave-dwelling bats exhibiting higher CoV prevalence due to population density and behaviour. These findings underscore the necessity for sustained surveillance efforts aimed at comprehending CoV dynamics within bat populations, especially concerning the risk of spillover events and viral evolution. Vital to this understanding is the monitoring of bat migration patterns, which serves as a crucial tool for elucidating CoV ecology and epidemiology. Such efforts are essential for ongoing research endeavours aimed at mitigating the potential for future zoonotic disease outbreaks.

Near or far: revision of distribution, breeding and winter ranges of two sibling Pipistrellus species (Chiroptera, Vespertilionidae) in Eastern Europe and the Caucasus

Abstract Knowledge of species distribution and, for migratory species, seasonal occurrence is particularly important for vulnerable and protected animals such as bats. The former European bat species Pipistrellus pipistrellus was split into two, Pipistrelus pipistrellus s.s. and Pipistrelus pygmaeus, over 20 years ago. However, their distribution, breeding and winter ranges as well as migratory status in Eastern Europe and the Caucasus remained obscure. In our study, we scrutinised records of both species and assessed the sex ratio during their breeding season in this region. We show that Pipistrellus pipistrellus s.s. has a significantly smaller range than previously assumed, being restricted to the southern part of the study area. On the contrary, Pipistrelus pygmaeus has a broader distribution, covering the Caucasus and Eastern Europe, up to ca. 59° N. Hence, all historical records and long‐distance movements of Pipistrellus pipistrellus sensu lato from Eastern Europe within the inferred allopatric occurrence of Pipistrelus pygmaeus should be attributed to Pipistrelus pygmaeus. The high portion of adult males in breeding localities, mass wintering within the breeding range and lacking evidence of long‐distance seasonal movements imply that Pipistrellus pipistrellus s.s. is a sedentary species. In Pipistrelus pygmaeus, the sex ratio among adults during the breeding season varies latitudinally. The female‐biased sex ratio, absence of mass wintering and the historical long‐distance recoveries of ringed individuals suggest that this species is migratory in Eastern Europe. The male‐biased sex ratio during the breeding season, along with late autumn records, suggests that the Caucasus represents its winter range.

Rapid and reliable method for identification of three medium-sized horseshoe bat species in Europe

Rapid and reliable method for identification of three medium-sized horseshoe bat species in Europe

Leaping on urban islands: further summer and winter range expansion of European bat species

Cities or urban areas are the new types of landscapes that have rapidly developed in the Anthropocene and generally mimic mountains and rock habitats. Such areas attract different vertebrate species that naturally prefer rocky habitats, for example, bats, which are common animal inhabitants of the cities in the Northern Hemisphere. Here we review records of four bat species (Hypsugo savii, Plecotus austriacus, Pipistrellus nathusii and P. pygmaeus) inhabiting human settlements in Ukraine, encompassing the period from 2011 to 2022. Over the last 20 to 30 years, the winter range of P. nathusii has shifted 200-300 km north, and now covers all Black Sea coast steppe regions of continental Ukraine. The Pl. austiacus range most likely covers the whole territory of Ukraine. We documented the first factual records of H. savii in continental Ukraine and the first winter records of P. pygmaeus for the country. Our observations clearly demonstrate colonization of newly formed urban landscapes by bats species from different ecological groups. Therefore, bats, same as some other mammalian species, can be considered beneficiaries of urbanization and urban heat islands.

BatNet: a deep learning‐based tool for automated bat species identification from camera trap images

AbstractAutomated monitoring technologies can increase the efficiency of ecological data collection and support data‐driven conservation. Camera traps coupled with infrared light barriers can be used to monitor temperate‐zone bat assemblages at underground hibernacula, where thousands of individuals of multiple species can aggregate in winter. However, the broad‐scale adoption of such photo‐monitoring techniques is limited by the time‐consuming bottleneck of manual image processing. Here, we present BatNet, an open‐source, deep learning‐based tool for automated identification of 13 European bat species from camera trap images. BatNet includes a user‐friendly graphical interface, where it can be retrained to identify new bat species or to create site‐specific models to improve detection accuracy at new sites. Model accuracy was evaluated on images from both trained and untrained sites, and in an ecological context, where community‐ and species‐level metrics (species diversity, relative abundance, and species‐level activity patterns) were compared between human experts and BatNet. At trained sites, model performance was high across all species (F1‐score: 0.98–1). At untrained sites, overall classification accuracy remained high (96.7–98.2%), when camera placement was comparable to the training images (&lt;3 m from the entrance; &lt;45° angle relative to the opening). For atypical camera placements (&gt;3 m or &gt;45° angle), retraining the detector model with 500 site‐specific annotations achieved an accuracy of over 95% at all sites. In the ecological case study, all investigated metrics were nearly identical between human experts and BatNet. Finally, we exemplify the ability to retrain BatNet to identify a new bat species, achieving an F1‐score of 0.99 while maintaining high classification accuracy for all original species. BatNet can be implemented directly to scale up the deployment of camera traps in Europe and enhance bat population monitoring. Moreover, the pretrained model can serve as a baseline for transfer learning to automatize the image‐based identification of bat species worldwide.

A species-level trait dataset of bats in Europe and beyond

Knowledge of species’ functional traits is essential for understanding biodiversity patterns, predicting the impacts of global environmental changes, and assessing the efficiency of conservation measures. Bats are major components of mammalian diversity and occupy a variety of ecological niches and geographic distributions. However, an extensive compilation of their functional traits and ecological attributes is still missing. Here we present EuroBaTrait 1.0, the most comprehensive and up-to-date trait dataset covering 47 European bat species. The dataset includes data on 118 traits including genetic composition, physiology, morphology, acoustic signature, climatic associations, foraging habitat, roost type, diet, spatial behaviour, life history, pathogens, phenology, and distribution. We compiled the bat trait data obtained from three main sources: (i) a systematic literature and dataset search, (ii) unpublished data from European bat experts, and (iii) observations from large-scale monitoring programs. EuroBaTrait is designed to provide an important data source for comparative and trait-based analyses at the species or community level. The dataset also exposes knowledge gaps in species, geographic and trait coverage, highlighting priorities for future data collection.

Characterising diel activity patterns to design conservation measures: Case study of European bat species

Although diel activity time is a major axis of species' niche space, very few conservation measures focus on preserving daily periods free of anthropogenic pressures. While the spatial ecology of bats has received much attention, less is known about their temporal ecology, the knowledge being dispersed in studies of limited taxonomical, spatial and temporal range. We used data from the French bat monitoring program based on citizen science and standardised acoustic recordings (4409 sites monitored and 9807 nights monitored from 2014 to 2020) to characterise the diel activity patterns of 20 bat species so that their consideration in mitigation measures can help conservation. We designed a method to extract times of key descriptors and describe bat activity distribution throughout the night. We found that bat species could be separated in three functional groups characterised by a crepuscular activity, an activity that occurs when it is completely dark or an intermediate activity. We showed variations of diel activity patterns depending on season. We argue that accounting for these complex diel activity patterns would help design efficient mitigation measures, for instance to reduce the exposure of bats to light pollution or wind turbines. Overall, we advocate multi-taxa approaches to design conservation policies adapted to both the temporal and spatial distributions of species.

Home is where the heat is: Thermoregulation of European bats inhabiting artificial roosts and the threat of heat waves

Abstract Anthropogenic land use changes, such as deforestation and commercial forestry, have substantially reduced natural roost sites for European bats. A common conservation solution is to provide artificial roosts (i.e. bat boxes), but there are concerns that these can become hotter than natural roosts in summer and could be death traps during heat waves. Nevertheless, females of several bat species form maternity colonies in these boxes, thus occupying hotter and more humid microclimates than solitarily roosting males. We tested if cooling efficiency and heat tolerance differ between sexes in European bats, and estimated the evaporative water requirements for bats living in bat boxes during hot summer days. We used indirect calorimetry and thermometry to quantify thermoregulation at high air temperatures (Ta) in four species of verspitilionid bats that regularly occupy artificial roosts. We measured resting metabolic heat production, evaporative water loss rates (EWL) and body temperature (Tb) at Ta between 28°C and 48°C during summer. We predicted that females have higher evaporative cooling efficiency (evaporative heat loss/metabolic heat production) than males, allowing them to reach their heat tolerance limit at higher Ta. We found no sex differences in maximum evaporative cooling efficiency, maximum Tb, and maximum Ta tolerated. However, the patterns of increasing EWL with Ta differed between sexes. Females tolerated higher Ta before increasing EWL than males and then rapidly increased EWL to higher values than males at the maximum Ta tolerated. These sex differences in heat dissipation strategies may reflect varying ecological and physiological constraints associated with different summer roosting habits. Synthesis and applications. Our study revealed that some small European bat species are already at risk of succumbing to lethal dehydration during present‐day heat waves, with daytime evaporative water requirements equivalent to ~30% of body mass in sun‐exposed boxes. For conservation managers working with common European bat species, particularly those in monoculture forests with woodcrete bat‐boxes, our physiologically informed recommendations include positioning boxes in diverse locations varying in aspect and sun exposure. This will ensure thermal heterogeneity of roost sites and provide a wide gradient of microclimate conditions, allowing for roost switching when necessary.

Spring showers put a dampener on reproduction success

Bat mothers invest incredible amounts of energy in raising a pup. Typically, bats mate in the autumn and hibernate over winter; however, the females do not become pregnant until the following spring and give birth in the summer. To sustain pregnancy, bats feed on insects, such as midges and flies that can become rarer when poor weather sweeps in. In addition, younger bats need to hone their insect-catching skills which can also impair their ability to raise pups. Bianca Stapelfeldt from the University of Greifswald, and colleagues from the Bat Research Project, Germany and the Nossentiner/Schwinzer Nature Park, Germany, set out to determine how weather affects the reproductive success of adult female Natterer's bats (Myotis nattereri) of different ages.Beginning in 1990 and continuing every year since, researchers have collected Natterer's bats from bat and bird boxes in the Nossentiner/Schwinzer Nature Park in Mecklenburg-Pomerania, Germany, between July and September. The researchers measured the body mass, forearm length (measurement of body size) and identified the bat's age (whether they were adult or juvenile), before marking the bats with forearm bands to keep track of individuals through the years. In addition, the scientists noted whether the adult females had given birth that year by assessing the fur around the nipple; if there was fur, then the bat likely did not have a pup, while a lack of fur meant that she had given birth to a pup that season. Over the decades, the team also monitored archived climate data from a nearby meteorological station in Goldberg, Germany, and identified the average and lowest temperatures, the daily precipitation levels and the overnight wind speeds and total precipitation levels from 2003 to 2020.The team found that over the 17-year period, the younger adult female bats had less success in birthing and rearing baby bats, compared with older adult females, likely because the younger mothers may be unable to provide themselves with the immense amount of energy required during pregnancy and when feeding their pups. The researchers speculate that younger adult bats may forgo pregnancy to avoid investing energy into a pup that they may be unable to raise. Interestingly, wetter springs also resulted in lower birth rates in younger adult bats, which was not seen with the older mothers. The researchers suspect that rainy periods make it difficult for the bats to echolocate and hunt for food and to stay warm. Therefore, poor weather may cause the bats’ body weight to reach a critical low, so that younger bats may forgo pregnancy altogether.In addition, the researchers identified a 2-week window (from the end of April to 11 May) where poor weather had the greatest negative impact on the females’ pregnancies. It is unknown when Natterer's bats become pregnant, but this 2-week critical period is the same time pregnancies begin for other bats across Europe. Since pups have little time to grow and prepare for hibernation, adult females cannot delay their pregnancies any later, and so may abandon pregnancies if they experience adverse weather during this pivotal period.Stapelfeldt and colleagues have successfully shown the impact of poor weather on the pregnancy and baby rearing by bat mothers using long-term monitoring of a bat population and the weather conditions they encounter. Climate change is an imminent threat worldwide and many European countries are likely to become increasingly wet during this critical period for bat pregnancies, which could dramatically affect the ability of bat populations to reproduce. Increases in rainfall during the spring may be a particular threat for European bat species at risk of extinction.

Alphacoronavirus in a Daubenton's Myotis Bat (Myotis daubentonii) in Sweden.

The ongoing COVID-19 pandemic has stimulated a search for reservoirs and species potentially involved in back and forth transmission. Studies have postulated bats as one of the key reservoirs of coronaviruses (CoVs), and different CoVs have been detected in bats. So far, CoVs have not been found in bats in Sweden and we therefore tested whether they carry CoVs. In summer 2020, we sampled a total of 77 adult bats comprising 74 Myotis daubentonii, 2 Pipistrellus pygmaeus, and 1 M. mystacinus bats in southern Sweden. Blood, saliva and feces were sampled, processed and subjected to a virus next-generation sequencing target enrichment protocol. An Alphacoronavirus was detected and sequenced from feces of a M. daubentonii adult female bat. Phylogenetic analysis of the almost complete virus genome revealed a close relationship with Finnish and Danish strains. This was the first finding of a CoV in bats in Sweden, and bats may play a role in the transmission cycle of CoVs in Sweden. Focused and targeted surveillance of CoVs in bats is warranted, with consideration of potential conflicts between public health and nature conservation required as many bat species in Europe are threatened and protected.

Going Bald — The Hairy Affair of Timing in Telemetry Studies: Moulting Activity in European Bat Species

Telemetry is a widely used method for radio-tracking bats. To minimize negative effects of attaching a tag, like bald spots during hibernation and nursery period, narrowing down the timing of the moult of bats is important. In this study, we investigated the moulting of 11 European bat species with a focus on Myotis daubentonii, Myotis myotis and Pipistrellus pipistrellus. Telemetry data were taken from a 20 years data base. For moulting activity bats were caught with mist nests during their activity period in 2019 and 2020. During data acquisition the condition of the hair was categorized using two different methods: visual hair growth and shed hair pulled off the bats' pelage. Both methods revealed the same results. In general, bats moulted once a year in mid-June (first moult: 17.06) until mid-August (last moult: 13.08), with a significant difference between adult males, reproductive females and non-reproductive females. Adult males (n = 197) and non-reproductive females (n = 60) moulted from mid-June (first moult: 17.06) to end of July (last moult: 27.07), while reproductive females (n = 216) moulted from beginning of July (first moult: 02.07) to mid-August (last moult: 17.08). This variance is probably caused by sex-specific energetic processes like pregnancy, lactation and spermatogenesis. When tagged before moulting season bats could regrow fur in the same year. As seen in recaptured bats (n = 31), tagged in or after this period bats stayed bald during hibernation and reproduction period until the following moulting season. Further studies are needed to specifically assess the impact of bald spots on hibernation and reproductive success. A preceding cost-benefit analysis of the expected knowledge gain versus the potential negative impact on individual and colony scale is recommended.

Torpor/hibernation cycle may enhance the risk of insecticides for bats: an in vitro study

Exposure to pollutants is considered one of the potential reasons of population declines in bats. In the context of previous studies, we managed to create and keep a wide collection of cell lines from European bat species. Liver cells were chosen for testing, as they represent the preferred model for toxicological studies. Bats are protected, cell lines replacing experimental animals thus represent a unique opportunity to examine effects of pollutants which animals are exposed to in their environments. Moreover, cell incubation temperature variation may simulate physiological states of heterothermic bats. Liver cell lines were cultivated to the required cell number. Exposure to five different concentrations of permethrin (PM) and imidacloprid (IMI) were used to determine cytotoxic effects of these pesticides on Nyctalus noctula-derived liver cells cultivated at 37 °C and 8 °C for 24 h. An assay based on the measurement of activity of lactate dehydrogenase released from damaged cells was used for quantitating cytotoxicity. Cytotoxicity of IMI ranged from 0% to 47% and from 56% to 67% at 37 °C and 8 °C, respectively. Cytotoxicity of PM ranged from 36% to 56% and from 43% to 88% at 37 °C and 8 °C, respectively. Permethrin was tested on the cells at an order of magnitude lower concentrations; even so, higher degree of cytotoxicity was recorded. Imidacloprid was more toxic to bat liver cells at a hibernation temperature than at body temperature of 37 °C.

The first record of a maternity colony of Kuhl’s pipistrelle Pipistrellus kuhlii (Chiroptera) in Poland

For four decades, there have been changes in the ranges of many bat species in Europe, particularly shifts in their northern limits. This phenomenon is more spectacular for migratory species than sedentary ones, especially for representatives of the genera Pipistrellus and Hypsugo. Kuhl’s pipistrelle Pipistrellus kuhlii (Kuhl, 1817) is the one of western Palaearctic bat species with conspicuous range expansion—in the last three decades, the species has rapidly expanded and colonised new territories both northwards and westwards. In Central Europe, two genetic lineages occur that are also quite different morphologically: P. kuhlii kuhlii (hereafter P. kuhlii) and P. kuhlii lepidus (hereafter P. lepidus). The contact zone between these two lineages passes through Hungary and Slovakia, although the real range of distinct lineages and/or morphotypes are still unclear. The first records of P. kuhlii from Poland (probably belonging to P. lepidus) come from Warszawa, central Poland (2004) and Zawiercie, southern Poland (2005): both specimens were males, found in December in buildings. Since then, there have been further reports of the presence of this species in Poland—occurring mostly in large cities along the valleys of large rivers such as the Wisła and Bug, from both periods of activity and hibernation. In subsequent years in Poland the occurrence of only P. lepidus has been confirmed, while P. kuhlii has been recorded from southern locations in the Carpathian Mountains in Slovakia. This paper describes the first record of this species from Poland, further indicating the existence of a maternity colony. In mid-July of 2020, a non-volant juvenile male was found in Kraków, Krowodrza district (50°04'11.7" N, 19°54'55.9" E). Initially poorly visible diagnostic features have become unambiguous with development and similar to those in P. kuhlii: narrow pale wing margin and orange penis colouration. After about two months in captivity, a mature individual capable of flying was released at the site where it was found. The presence of a maternity colony indicates that this species (i) has been part of the Polish fauna for several years, and (ii) its range in Poland possibly expands much further north.

Quantitative evaluation of individual food intake by insectivorous vespertilionid bats (Chiroptera, Vespertilionidae)

ABSTRACTInsectivorous bats provide important ecosystem services, especially by suppressing and controlling the insects’ biomass. To empirically quantify the number of insects consumed by European vespertilionid bats per night, we estimated their ratio of dry mass of feces to mass of consumed insects. This study combines the results of feeding in captivity and the data obtained in field surveys; dry mass of feces was measured in both cases. In captivity, we analyzed the effect of species, age and sex of bats, species of insects consumed and the mass of food portion on the dry mass of feces. Using coefficients of the regression model, we estimated the number of insects consumed by free-ranging bats based on dry mass of their feces. According to our estimates, on average, one individual of one of the largest European bat species, Nyctalus noctula, consumes 2.2 g (ranging from 0.5 to 8.2 g) of insects per one feeding night, while the smallest European bats of genus Pipistrellus consume 0.4 g (ranging from 0.1 to 1.3 g), further confirming the importance of insectivorous bats for ecosystem services. This publication offers the novel method for the estimation of insects’ biomass consumed by bats.

Determinants of defence strategies of a hibernating European bat species towards the fungal pathogen Pseudogymnoascus destructans

Pseudogymnoascus destructans (Pd), the causative agent of white-nose syndrome in North America, has decimated bat populations within a decade. The fungus impacts bats during hibernation when physiological functions, including immune responses, are down-regulated. Studies have shown that Pd is native to Europe, where it is not associated with mass mortalities. Moreover, genomic and proteomic studies indicated that European bats may have evolved an effective immune defence, which is lacking in North American bats. However, it is still unclear which defence strategy enables European bats to cope with the pathogen. Here, we analyzed selected physiological and immunological parameters in torpid, Pd infected European greater mouse-eared bats (Myotis myotis) showing three different levels of infection (asymptomatic, mild and severe symptoms). From a subset of the studied bats we tracked skin temperatures during one month of hibernation. Contrasting North American bats, arousal patterns remained unaffected by Pd infections in M. myotis. In general, heavier M. myotis aroused more often from hibernation and showed less severe disease symptoms than lean individuals; most likely because heavy bats were capable of reducing the Pd load more effectively than lean individuals. In the blood of severely infected bats, we found higher gene expression levels of an inflammatory cytokine (IL-1β), but lower levels of an acute phase protein (haptoglobin), reactive oxygen metabolites (ROMs) and plasma non-enzymatic antioxidant capacity (OXY) compared to conspecifics with lower levels of infection. We conclude that M. myotis, and possibly also other European bat species, tolerate Pd infections during torpor by using selected acute phase response parameters at baseline levels, yet without arousing from torpor and without synthesizing additional immune molecules.

Revealing the role of past and current climate in shaping the distribution of two parapatric European bats, Myotis daubentonii and M. capaccinii

In this contribution, we aim at determining the role of climate in shaping the current and historical (Last Glacial Maximum and Middle Holocene) distributions of two parapatric bat species (Myotis daubentonii and Myotis capaccinii) in Europe, using ensemble Habitat Suitability Modelling (HSM). Model projection to current climatic conditions predicted distributions largely coherent with the ones observed for the two species in the study area. Temperature- and precipitation-linked variables well accounted for the observed parapatry of the two target species. Moreover, areas of co-occurrence turned out to be those where the main ecological needs concerning the most important range-limiting variables are met for both species. Model projections to past scenarios allowed us to hypothesize the effects of climatic oscillations over the distribution of the two species during the Late Pleistocene and Holocene. Extreme range contractions during the Last Glacial Maximum and the subsequent expansions during Middle Holocene were predicted, consistently with general patterns of post-glacial recolonization routes of many temperate bat species in Europe. Our findings are largely coherent with recent phylogeographic studies investigating the two target species, thus corroborating the validity of potential distribution scenarios obtained from the models and, more importantly, confirming the great influence that glacial cycles had in shaping the biogeography of the European fauna.