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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, Psorergatoides kerivoulae (Fain, 1959). The parasite causes cutaneous lesions on the wing membranes of the greater moused-eared bat, Myotis myotis (Borkhausen, 1797) and the lesser moused-eared bat, Myotis blythii (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.

Myotis bucharensis is one of the least studied Palaearctic bat species, known from only three localities in Tajikistan and Uzbekistan and not reported since 1965. In autumn 2019, a male Myotis captured in Zerafshan river basin in Tajikistan was later identified as M. bucharensis based on tail and tibia proportions and strongly displacement of posterior small premolars. The identification was then confirmed by morphometric analyses supporting that M. bucharensis is specifically different but represents a part of the Myotis frater complex. Analyses of one mitochondrial (cyt b) and one nuclear gene (RAG2) were performed for the first time for M. bucharensis. According to these genetic results, this form is indeed a member of the «daubentonii» clade, which includes all known frater-like Myotis, and most likely represents a sister species to M. longicaudatus. Record of the alive specimen M. bucharensis has valuable implication for bat conservation in Tajikistan.

Bats rely heavily on acoustic signals in order to communicate with each other in a variety of social contexts. Among those, agonistic interactions and accompanying vocalizations have received comparatively little study. Here, we studied the communicational behaviour between male greater mouse-eared bats (Myotis myotis) during agonistic encounters. Two randomly paired adult males were placed in a box that allowed us to record video and sound synchronously. We describe their vocal repertoire and compare the acoustic structure of vocalizations between two aggression levels, which we quantified via the bats’ behaviour. By inspecting thirty, one-minute long encounters, we identified a rich variety of social calls that can be described as two basic call types: echolocation-like, low-frequency sweeps and long, broadband squawks. Squawks, the most common vocalization, were often noisy, i.e. exhibited a chaotic spectral structure. We further provide evidence for individual signatures and the presence of no...

Bats, some species of rodents and some birds are able to save energy during the summer period by decreasing their body temperature and falling into torpor. Some studies indicate that torpor prevents sleeping and causes effects similar to sleep deprivation. Impairment of processes stabilizing memory slows down learning accuracy and speed. We conducted two experiments to test whether greater mouse-eared bats, Myotis myotis, which commonly use torpor during the summer period, experience a trade-off between energy savings and learning abilities. We compared learning speed and accuracy in bats that were exposed to low (7°C) and higher ambient temperatures (22°C) between training and experimental sessions. Tests were conducted in experiments with food reward (food search) and without food reward (perch search). Time spent with the skin temperature above 30°C was significantly longer for bats exposed to 22°C than for those exposed to 7°C, and longer in experiments with food reward than without food reward. We observed only a very weak tendency for better accuracy and shorter search times in bats exposed to 22°C than in those exposed to 7°C. Our data indicate that memory consolidation of bats under natural conditions is not affected by daily torpor when bats are in good condition and may therefore defend against a rapid fall into torpor. We suggest that homeostatic processes connected with the circadian rhythm allow protection of the consolidation of memory for relatively simple tasks despite time spent in torpor.

Loss of roost sites in buildings represents the major threat to Myotis myotis populations in the Czech Republic. To identify features that may determine roost selection by M. myotis, we compared a range of structural and habitat variables for 17 maternity roosts and 17 unoccupied, but potentially suitable, buildings in the Moravian Karst (Czech Republic). Roosts and control sites were mainly in churches and chateaus and all were detached from the surrounding buildings and uninsulated. The only difference between habitat surrounding roost and control buildings was that roost buildings had relatively lower amounts of hedges as linear connective features. Our results suggest that bats do not select building features from among suitable detached and uninsulated churches and chateaus and that bats tend to select building roosts that are not connected to woodland by hedges. Protection of roosts is an important conservation issue for female M. myotis and suitable roost sites such as detached and uninsulated buildings that are not connected to woodland by hedges are important maternity roosting resources.

The risk of parasite infection grows with the size of host aggregations, which, in turn, may also depend on host sex and age and the quality of environmental resources. Herein, we studied the relationship between ectoparasitic infections with the wing mite (Spinturnix myoti) and the size of the breeding colonies, sex, age, and body condition index (BCI) of its host, the greater mouse-eared bat (Myotis myotis). The influence of environmental quality in the Carpathian Mountains (Poland) was also examined. We found significant differences in mite abundance and BCI between different breeding aggregations of the greater mouse-eared bat and also between the host sex/age categories. The most heavily infected bats were adult M. myotis females, while young males appeared to be the least infected. The BCI differed significantly between the sexes in young bats (males had a higher BCI than females) and also between colonies. No significant differences in the BCI were found for adult females. We did not find any relationship between the infestation rate of M. myotis, their colony size, the quality of environmental resources (percentage of forest cover around the colony), or the BCI. The prevalence of the various developmental stages of the mites did not differ between the host sex/age categories; however, differences were found in the sex ratios of deutonymphs and adult mites between adult M. myotis females. We predict that parasite load may not be dependent on colony size itself, but mainly on microclimatic factors, which are in turn directly correlated with colony size.

Transposable elements, mobile DNA sequences present in virtually all organisms, have previously been thought to be inactive in mammals. However, current studies have revealed the first evidence of recent piggyBac and hAT activity in Myotis lucifugus. The objective of this study was to further characterize the abundance and diversity of five transposable elements in various Myotis bats. The five elements were confirmed present in 10 species (M. ciliolabrum, M. californicus, M. velifer, M. yumanesis, M. lucifugus, M. thysanodes, M. volans, M. austroriparius, and M. keaysi) spanning the new world clade of Myotis using PCR. Preliminary sequence data focusing on the transposase region was collected and analyzed for two of the elements; hAT3 data set contained 1200 bp and piggyBac1 contained 942 bp. The older hAT3 element had a mean sequence diversity of 1.88%; whereas the younger piggyBac1 element had little diversity (0.01%). A small number of polymorphic sites within the sequence of a single indivi...

In the last century bat populations significantly declined mainly due to habitat fragmentation and degradation. As management-dependent species, bats need appropriate monitoring programs for the implementation of sound conservation strategies. However, bats’ small size, high mobility, elusiveness and nocturnal lifestyle make them difficult to survey. Non-Invasive Genetic Sampling (NIGS) may offer safe and cost-effective solutions, but requires well-planned sampling strategies, informative molecular markers and reliable laboratory protocols. Here we developed a NIGS protocol for species and individual identification of three mouse-eared bats, the Geoffroy’s bat (Myotis emarginatus), the long-fingered bat (Myotis capaccinii) and the Daubenton’s bat (Myotis daubentonii). Species identification was accomplished by mitochondrial (mt) DNA sequencing of reference tissue (n=49) and droppings (n=285) from Central-Northern Italy. In addition, we optimized a multiplex panel of seven microsatellites suitable for species and individual identification of the three species from droppings. We obtained a good success with mtDNA sequencing (245/285; 86%) and microsatellite genotyping (129/245; 53%). All microsatellites were successfully amplified with low error rates, and were polymorphic in the three Myotis species, with probabilities of identity 6 0.001 and observed heterozygosities of Ho=0.48 in M. emarginatus, 0.62 in M. capaccinii and 0.71 in M. daubentonii. Our protocol represents a useful tool for population genetic studies on mouse-eared bats that could likely be extended to other bat species and provide useful information to implement effective conservation plans.

During monthly bat surveys carried out in winters of 2008/2009 and 2009/2010 we studied clustering behavior of greater mouseeared bats (Myotis myotis) hibernating in the Miedzyrzecz Fortified Front (MFF) in western Poland. Since the behavior of hibernating bats is usually affected by varying environmental conditions we measured changes in the ambient temperature (T a ) and water vapor pressure (WVP) and their variability in the selected areas and analyzed the relationship between clustering behavior of hibernating bats and abiotic conditions. In both winters, the number of solitarily roosting individuals of M. myotis decreased from autumn to spring while the highest number of bats hibernating in clusters was recorded in the middle of winter. The number of clusters did not change significantly over the winter, but the number of individuals within a particular cluster increased from November (median = 5, inter-quartile range, IQR = 5–8) to March (median = 20, IQR = 14–35.5). The changes of the clusters' size were best explained by a mixed model with WVP and the variability in WVP over the 20 days prior to the bat survey as explanatory variables. As WVP and the variability in WVP decreased, the number of individuals in a cluster increased. Also, Ta affected the size of clusters. However, neither of the models supported the hypothesis of the effect of variability of T a on clustering of M. myotis. We propose that huddling enables bats to reduce evaporative water loss during the middle and at the end of the hibernation and reduces costs of spring arousals, perhaps by synchronizing them between clustered individuals and thus allowing the use of passive re-warming.

During critical periods of food shortage or variable climatic conditions, the choice of an appropriate host can increase the survival and reproductive performance of parasites. In turn, one of the unique adaptations to periodical food shortages is hibernation, which is often found among insectivorous bat species in the temperate zone. While hibernating, bats are completely defenseless against both predators and ectoparasites, their immune and endocrine systems are diminished, and survival is dependent on the accumulated fat reserves. Differences in the health status or in the rate of consumption of the resources might also explain species-specific differences in ectoparasite abundance, especially between closely related host species, such as the greater mouse-eared bat (Myotis myotis) and the lesser mouse-eared bat (M. blythii) during hibernation. In the present study, the abundance of two ecologically distinct (summer and winter) types of ectoparasites was examined in terms of its influence on the body condition and hemoglobin content of the two host species. The effects of demographic factors, such as host sex and age, were also investigated. Despite a similar pattern of deteriorating body condition and hemoglobin concentration, M. myotis was more parasitized than was M. blythii. The marked decrease in hemoglobin content in first-year females of both host species correlated with the highest parasite load and indicated a risk of anemia. At the intraspecific level, ectoparasite abundance was not correlated with body condition (resources), but it negatively affected hemoglobin content; however, this mostly concerned M. blythii, which had a lower parasite load. Therefore, it can be concluded that interspecific differences in ectoparasite abundance may result from parasites selecting the host species that is less sensitive to their activity. In turn, in summer ectoparasites, the preference for female hosts is probably attributable to the likelihood of reinfection rather than to an effect of host resources or health status. The absence of sex-based preferences in winter ectoparasites could be explained by equal host availability.

SUMMARYThe two sibling mouse-eared bats, Myotis myotis and M. blythii, cope with similar orientation tasks, but separate their trophic niche by hunting in species-specific foraging microhabitats. Previous work has shown that both species rely largely on passive listening to detect and glean prey from substrates, and studies on other bat species have suggested that echolocation is `switched off' during passive listening. We tested the hypothesis that mouse-eared bats continuously emit echolocation calls while approaching prey. Echolocation may be needed for orientation while simultaneously listening for prey. Because these sibling species forage in different microhabitats and eat different prey, we also compared their echolocation behaviour and related it to their ecology. Both species used echolocation throughout prey approach, corroborating a functional role for echolocation during gleaning. Captive bats of both species emitted similar orientation calls, and pulse rate increased during prey approach. Between the search to approach phases, call amplitude showed a sudden, dramatic drop and bats adopted `whispering echolocation' by emitting weak calls. Whispering echolocation may reduce the risks of masking prey-generated sounds during passive listening, the mouse-eared bats' main detection tactic; it may also avoid alerting ultrasound-sensitive prey. In several cases M. myotisemitted a loud buzz made of 2-18 components when landing. We hypothesise that the buzz, absent in M. blythii at least when gleaning from the same substrate, is used to assess the distance from ground and refine the landing manoeuvre. Our findings have implications for niche separation between sibling species of echolocating bats, support a role for echolocation during passive listening and suggest a functional role for buzzes in landing control.

Two sympatrically occurring bat species, the greater mouse-eared bat (Myotis myotis (Borkhausen, 1797)) and the lesser mouse-eared bat (Myotis blythii (Tomes, 1857)) (Chiroptera, Vespertillionidae), share numerous similarities in morphology, roosting behaviour, and echolocation and are often difficult to distinguish. However, despite these similarities, their foraging behaviour is noticeably different. Our aim was to examine the extent to which these different foraging strategies reflect morphological adaptation. We assessed whether the morphology of the wing, body, and tail differed between M. myotis and M. blythii. In addition, in a laboratory experiment involving an obstacle course, we compared differences in manoeuvrability by relating them to our morphological measurements. The two species differed in their overall size, wing-tip shape, and tail-to-body length ratio. The generally smaller sized M. blythii performed better in the obstacle course and was therefore considered to be more manoeuvrable. Although differences in wing-tip shape were observed, we found the most important characteristic affecting manoeuvrability in both species to be the tail-to-body length ratio. Additionally, when we compared two bats with injured wing membranes with unharmed bats of the same species, we found no difference in manoeuvrability, even when the wing shape was asymmetric. We therefore postulate that morphometric differences between the two species in their overall size and, more importantly, in their tail-to-body length ratio are the main physical characteristics providing proof of adaptation to different foraging and feeding strategies.

This paper describes the feeding behaviour and foraging strategy of the sibling mouse-eared bat species Myotis myotis and M. blythii under natural conditions. In the Swiss Alps, the main prey of M. myotis consisted of carabid beetles (46% by volume), whereas bush crickets contributed most to M. blythii s and when bush crickets were unavailable in May and June, they were replaced by cockchafers in M. blythii s foraging behaviour was highly flexible. The results suggest that mouse-eared bats are opportunistic predators that maximize their average rate of food intake by balancing habitat selection.

Echolocating bats use the echoes from their echolocation calls to perceive their surroundings. The ability to use these continuously emitted calls, whose main function is not communication, for recognition of individual conspecifics might facilitate many of the social behaviours observed in bats. Several studies of individual-specific information in echolocation calls found some evidence for its existence but did not quantify or explain it. We used a direct paradigm to show that greater mouse-eared bats (Myotis myotis) can easily discriminate between individuals based on their echolocation calls and that they can generalize their knowledge to discriminate new individuals that they were not trained to recognize. We conclude that, despite their high variability, broadband bat-echolocation calls contain individual-specific information that is sufficient for recognition. An analysis of the call spectra showed that formant-related features are suitable cues for individual recognition. As a model for the bat's decision strategy, we trained nonlinear statistical classifiers to reproduce the behaviour of the bats, namely to repeat correct and incorrect decisions of the bats. The comparison of the bats with the model strongly implies that the bats are using a prototype classification approach: they learn the average call characteristics of individuals and use them as a reference for classification., Author Summary Animals must recognize each other in order to engage in social behaviour. Vocal communication signals could be helpful for recognizing individuals, especially in nocturnal organisms such as bats. Echolocating bats continuously emit special vocalizations, known as echolocation calls, and perceive their surroundings by analyzing the returning echoes. In this work we show that bats can use these vocalizations for the recognition of individuals, despite the fact that their main function is not communication. We used a statistical approach to analyze how the bats could do so. We created a computer model that reproduces the recognition behaviour of the bats. Our model suggests that the bats learn the average calls of other individuals and recognize individuals by comparing their calls with the learnt average representations.

The approach phase of landing vespertilionid bats ends with a group of calls, which either consists of buzz I alone or buzz I and buzz II. To understand the possible role of buzz II, we trained Myotis myotis to land on a vertical grid, and compared the flight and echolocation behavior during approach in trials with and without buzz II. During the approach, we did not find any differences in the echolocation behavior until the end of buzz I which indicated whether buzz II was emitted or not. However, bats flying from the periphery of the flight channel, such that they had to make a small turn at the very last moment, finished the sequence with a buzz II. Bats flying on a rather stereotyped trajectory near the center of the flight channel without last instant corrections emitted buzz I alone. Our results indicate that buzz II occurred only on trajectories that implied a higher risk to fail at landing. The information delivered by buzz II reaches the bat too late to be used for landing. Therefore, we hypothesize that buzz II may help the bats to evaluate unsuccessful attempts and to eventually react adequately.

The greater mouse-eared bat, Myotis myotis Borkhausen, is recorded from Syria and Lebanon and a new subspecies is described, type locality 2 km east of Amchite, Lebanon. This bat exists together with the lesser mouse-eared bat, Myotis blythi Tomes, in certain localities in Syria and Lebanon. The forms M. m. omari Thomas (type locality Derbent, Iran) and M. m. risorius Cheesman (type locality Shiraz, Iran) are considered to be races of M. blythi Tomes, and it is considered likely that risorius is a synonym of omari .