Abstract Peripheral island populations are often especially vulnerable to environmental change, yet they may also represent unique components of biodiversity. We assessed long-term population change in the Egyptian fruit bat (Rousettus aegyptiacus) on Cyprus, the only insular and geographically isolated population of this pteropodid in Europe, and evaluated two non-exclusive explanations for its decline: roost disturbance and reduced food availability. We analysed roost counts from 21 underground sites monitored between 2005 and 2022 and modelled temporal trends in commercially produced fruits used by the species. The monitored population declined from c. 7200 to c. 1050 individuals, corresponding to an estimated decrease of 85.4%. The decline was steepest during 2005–2011, slowed during 2012–2017, and was followed by partial recovery in 2018–2022. Colonies in easily accessible roosts declined significantly faster than those in less accessible roosts, consistent with an important role of human disturbance. Fruit production showed strong long-term declines and multiple structural breaks clustered in the mid-2000s, coinciding with the most severe phase of population decline and a major drought period on Cyprus. The fate of the missing portion of the population remains uncertain. Although large-scale mortality cannot be excluded, there was no clear evidence of widespread starvation-related mortality, and emigration to nearby mainland areas remains a plausible but untested explanation. Overall, our results indicate that the collapse of this peripheral island population was most likely driven by a combination of roost disturbance and reduced food availability associated with climate-related environmental change, highlighting the urgent need for strict roost protection and measures to secure food and water resources.

Insular bat populations are particularly vulnerable to human disturbance and environmental change, yet long-term demographic data remain scarce. The Egyptian fruit bat (Rousettus aegyptiacus) is the only native fruit bat in Europe, with Cyprus harbouring one of its most isolated populations. We analysed long-term monitoring data from 21 roosts surveyed between 2005 and 2022 to quantify population trends and evaluate the roles of roost accessibility and food availability. Population trends were estimated using log-linear TRIM models, while generalized linear mixed models tested whether trends differed between roosts with contrasting accessibility. Commercial fruit production was analysed as a proxy for food availability. The population declined from approximately 7200 individuals in 2005 to about 1050 in 2022, corresponding to an overall decline of 85.4% and an average annual decrease of 8.8%. Trend analyses identified three phases: a rapid decline (2005–2011), a slower decline (2012–2017), and a partial recovery after 2018. Colonies in easily accessible roosts declined significantly faster than those in less accessible roosts, indicating that human disturbance likely contributed substantially to the population collapse. Commercial fruit production also declined markedly during this period, coinciding with exceptional drought on Cyprus. Our results suggest that roost disturbance was a major driver of the decline, whereas reduced food availability, likely associated with increasing aridity and climate-driven changes in agricultural production, further contributed to population losses. Our findings highlight the need for strict protection of roosts and suggest that securing food and water resources may represent an important complementary conservation measure.

Much of the research into white-nose disease has focused on the hibernation period, while the pathogenic fungus Pseudogymnoascus destructans is actively infecting the bat host. Previous research has found large differences between the susceptible North American Myotis lucifugus and the tolerant European Myotis myotis, suggestive of immunopathology in the former, and a beneficial lack of strong response in the latter. Here, we examined gene expression in these species both during the late-hibernation period and a month after emergence from hibernation, during healing from infection. We utilised paired sampling, collecting wing tissue that was positive and negative for fungal infection fluorescence, to examine changes in wholetranscriptome gene expression that were local to sites of infection at two time points: pre-emergence and 30 days post-emergence from hibernation. Positive samples were contrasted between the two time points to examine longitudinal changes. During the pre-emergence period, local inflammatory responses were observed in both M. myotis and M. lucifugus. Immune responses between the tolerant and susceptible species were dissimilar, favouring Th1 and Th17 cytokine responses, respectively. This lends weight to immunopathology as a contributing factor to mortality in M. lucifugus. Continual immune responses may not only contribute to immunopathology and host mortality but also have important carry-over effects on reproduction and subsequent pre-winter fattening, affecting population viability over a longer period of time than previously considered.

Aim Explaining the phenomenon of high biodiversity of biota remains one of the most significant challenges in the natural sciences, especially when it concerns long-lived, highly mobile and cryptic taxa. Underground hibernation sites, where temperate bats congregate in winter, are key biodiversity hotspots that are systematically monitored in many countries and represent important population data. We investigated bat species richness and abundance in relation to hibernacula, considering multiple scale features-climate, ecoregion, topography, landscape use and site characteristics.Location Central Europe, Czech Republic.Taxon Bats (Chiroptera).Methods We used unpublished data from a long-term monitoring programme of bat censuses at hibernation sites (caves, mines, cellars and bunkers) in the Czech Republic. To test the possible effects of four features (environmental, climatic, entrance position and inner roost parameters) on bat species richness and abundance, we ran Generalized Linear Models for each dependent variable. Further, an additional step was performed to eliminate multicollinear variables using variance inflation factors.Results Species richness was most strongly influenced by temperature seasonality, with additional effects from hibernaculum entrance height and length. In the total abundance models, the most influential predictors were hibernaculum accessibility and complexity of the hibernaculum, determined by the profile of the corridors and denivelation. Climate and internal spatial features of hibernacula were stronger predictors of bat occupancy and species richness than broad-scale environmental variables.Main Conclusions Our study jointly analysed how climate, land use, entrance position and the internal structure of a hibernaculum influence the species richness and abundance of bats. Our results show that, in addition to relationships documented in previous studies, the internal structure of hibernacula is of fundamental importance in structuring bat assemblages in hibernation sites and in the distribution of certain species populations.

In recent years, in combination with climate change and dry summers, geometrids have caused damage to economically important forest trees, particularly oak. We focused on their co-occurring predators, the forest-dwelling bats, and their potential to reduce the number of pest geometrids. To quantify the aggregation response of bats, we used acoustic monitoring of flight activity, availability of moth imagos, and genetic analysis of their faeces. Our results show that even in the presence of massive outbreaks of geometrids, bat foraging activity decreases as winter approaches. Furthermore, our results show that for those bats that were active, the overabundant geometrids were not their main prey. Lunar marbled brown (Drymonia ruficornis), chestnut moth (Conistra vaccinii) and red-headed chestnut moth (Conistra erythrocephala;Noctuidae) were foraged as often or even more often than overabundant geometrids. Our results show that opportunistic behaviour of temperate bats is not evident at lower temperatures and that reasons other than abundance and accessibility of prey determine their prey preferences. Therefore, season and predator preferences may significantly affect the ecological services provided by bats.

Bats, the only mammals capable of true flight, provide a unique opportunity to study the transmission of their ectoparasites. Transmission typically occurs intentionally and, if successful, can lead to new infestations. Bat bugs (Cimex pipistrelli) are seldom found on bats captured in mist nets, raising questions about their transmission by bats over long distances. Among the Palaearctic bat species, Nyctalus noctula was most frequently observed carrying bugs when mist-netted outside their roosts. Therefore, we aimed to investigate whether different bat species vary in the number of transmitted bugs. Previous research indicated that mated female cimicids, such as C. lectularius, tend to leave their colonies to initiate new infestations, which we hypothesized would also apply to bat bugs. To test our hypotheses, we used three bat species and examined both mated and virgin females to compare the number of bat bugs on bats emerging from bat boxes during aviary sessions. Our findings revealed that Myotis daubentonii had the fewest bat bugs, while Myotis myotis and Nyctalus noctula had significantly higher counts. Notably, N. noctula harboured more unfed bugs than M. myotis. In addition, the total number of mated females found on the body of N. noctula was higher than the number of virgin females, but the difference between the number of mated and virgin females per session was not significant. Our experiments indicate that bat bugs preferentially disperse on larger bats, and that they feed for longer durations on N. noctula compared to M. myotis, making N. noctula a more effective vector for bat bugs.

Rearing common bed bugs (Cimex lectularius L.) and other hematophagous insects is essential for basic, medical, and pest-control research. Logistically, acquiring fresh blood can be a challenge, while biologically, the eventual effects of different rearing and blood preparation protocols on bed bug genotype and phenotype pose a risk of biased research results. Using bed bug populations that are either bat- (BL) or human-related (HL), we tested the short- and long-term effects of rearing bugs on live bats or human volunteers, or artificially on CPDA (citrate phosphate dextrose, adenine)-treated blood, measuring meal size, body size, and fertility. We found that artificial feeding did not affect meal size compared with feeding on natural hosts. Long-term rearing across many generations of HL on CPDA-preserved blood led to reduced body size and fertility compared with populations reared on human volunteers. Blood preservatives increased the proportion of sterile eggs even after a single feed. Finally, our results indicated that laboratory reared bed bugs were smaller, regardless of the blood source, than wild bugs. Similar effects of artificial feeding or laboratory rearing alone should be considered in future studies using bed bug cultures to choose an appropriate rearing protocol. With regard to switching between bat and human hosts, HL took smaller meals and BL had lower fertility when fed on bats than when fed on humans. We attribute these results to methodological constrains, specifically the inconsistency of bat feeding, rather than to host specialization. Nevertheless, BL can be easily reared using human blood and artificial feeding systems.

Diurnal flight activity in otherwise strictly nocturnal bats has typically been linked to random disturbance from day roosts, an urgent need to balance food shortage caused by adverse weather during nighttime, or the absence of diurnal predators. However, migration may be another reason why bats fly during daylight, at least in some areas. Using community-science data collection, we obtained more than 500 records of over 15,000 bats displaying diurnal flight activity, suggesting that it is relatively common in Central Europe. The vast majority of sightings were of common noctules (Nyctalus noctula), with most records concentrated in spring and autumn. The seasonal dynamics of diurnal flights exactly coincided with migratory periods, and directional movements in autumn-when diurnal activity was most frequent and included highest numbers of observed bats-suggest that the behavior may ultimately be linked to migration ecology. The highest frequency of diurnal flights in autumn coincided with highest body mass in the studied territory, thereby refuting the hypothesis of early roost emergence due to poor body condition or decreased predation risk related to increased maneuverability. A shift from strictly nocturnal to partly diurnal activity may balance increased energetic demands imposed by migration, which is temporally synchronized with periods of cold nights when prey density is limited. Common noctule diurnal activity during the migratory period may be beneficial as they can acquire energy by foraging on daily abundant prey while saving nighttime for long endurance flights-alternatively, they may forage on the way to their migratory destination, thereby saving time. Predation risk from diurnal predators may be significantly decreased by choosing high flight altitudes, as observed particularly during autumn. We suggest that observations on the geographic distribution of diurnally flying noctules may help identify migration corridors. Using community-science data, we obtained more than 500 records of over 15,000 bats displaying diurnal flight activity. The vast majority of bats were common noctules (Nyctalus noctula) and given the synchronization of most records into spring and autumn, we link this unusual activity to their migration ecology.

Disease can act as a driving force in shaping genetic makeup across populations, even species, if the impacts influence a particularly sensitive part of their life cycles. White-nose disease is caused by a fungal pathogen infecting bats during hibernation. The mycosis has caused massive population declines of susceptible species in North America, particularly in the genus Myotis. However, Myotis bats appear to tolerate infection in Eurasia, where the fungal pathogen has co-evolved with its bat hosts for an extended period of time. Therefore, with susceptible and tolerant populations, the fungal disease provides a unique opportunity to tease apart factors contributing to tolerance at a genomic level to and gain an understanding of the evolution of non-harmful in host-parasite interactions. To investigate if the fungal disease has caused adaptation on a genomic level in Eurasian bat species, we adopted both whole-genome sequencing approaches and a literature search to compile a set of 300 genes from which to investigate signals of positive selection in genomes of 11 Eurasian bats at the codon-level. Our results indicate significant positive selection in 38 genes, many of which have a marked role in responses to infection. Our findings suggest that white-nose syndrome may have applied a significant selective pressure on Eurasian Myotis-bats in the past, which can contribute their survival in co-existence with the pathogen. Our findings provide an insight on the selective pressure pathogens afflict on their hosts using methodology that can be adapted to other host-pathogen study systems.

Bats are known reservoirs of various emerging pathogens, and have recently been found to host a novel hantavirus, named Brno loanvirus (BRNV), from the Mammantavirinae subfamily (family Hantaviridae, order Bunyavirales). Here we report BRNV detection in bats from the urban area of Brno, Czech Republic in March 2022. Specifically, we uncovered a high prevalence of BRNV (8.8%, 5/57) among hibernating bats (Nyctalus noctula) in urban area, which poses a risk of human exposure. The positive bats included adult females (3/9 positive), a juvenile female (1/32 positive), and an adult male (1/6 positive). All 10 juvenile males were negative. We used RT-qPCR to quantify the BRNV RNA levels in various bat organs, which yielded positive results for viral RNA in organs, including the kidneys, heart, spleen, brain, liver, lung, and gut, and in body cavity fluid. Among all tested organs, the liver showed the highest levels of viral RNA in 4 out of 5 animals examined (average Ct value of 20.8 ± 7.4).

Human development and induced activities significantly affect the natural functioning of ecosystems and hence landscape connectivity. Ecological corridors are essential for maintaining structural as well as functional connectivity in cultural landscapes for wildlife, while providing interchange between core areas. In two pilot areas in the north-western and eastern part of Austria, ecological corridors were delineated using a geographic information system (GIS). The pilot areas are key to preserving ecological connectivity and are located along important international migration corridors (Bohemian Forest-Northern Alps corridor, Alpine-Carpathian corridor). Both areas are situated in highly human-altered and therefore dissected as well as fragmented landscapes. A one-year monitoring campaign using camera traps was carried out at selected locations along proposed ecological corridors in the cultural landscape and at wildlife crossings structures (WCSs) at intersections with road infrastructure. The monitoring was focused on mammals with a total of 18 species being observed. The most abundant species were roe deer, European hare and wild boar. European otter, European beaver, golden jackal and wildcat have only rarely been observed. Mammal species richness was positively correlated with the presence of vegetation cover and the coefficient of ecological stability (CES). The insights obtained can be used for recommendations and support in planning the planting of vegetation (use of grasslands, scattered and continuous woody vegetation, agroforestry systems) on the sites and in the vicinity of ecological corridors. The green bridges (wildlife overpasses) were used more frequently as well as by a larger number of mammal species compared to other studied WCSs showing characteristics that are less favourable for animals. The effectiveness of WCSs is mainly influenced by human activities, resulting in the recommendation to limit them on WCSs located along the routes of ecological corridors. We point out that actual wildlife migration corridors are likely to differ from designated data-driven ecological corridors generated by spatially explicit models, because these generally do not take into account all factors relating to the effectiveness of corridors. Our results suggest, that the application of the concept of functional connectivity is able to enhance the quality of ecological corridor designations, since usually they are based only on the concept of structural connectivity. For this reason, further studies are needed to help understanding factors and their specificities influencing the interplay between structural and functional connectivity of ecological corridors.

The common bedbug Cimex lectularius is a widespread ectoparasite on humans and bats. Two genetically isolated lineages, parasitizing either human (HL) or bat (BL) hosts, have been suggested to differentiate because of their distinct ecology. The distribution range of BL is within that of HL and bedbugs live mostly on synanthropic bat hosts. This sympatric co-occurrence predicts strong reproductive isolation at the post-copulatory level. We tested the post-copulatory barrier in three BL and three HL populations in reciprocal crosses, using a common-garden blood diet that was novel to both lineages. We excluded pre-copulation isolation mechanisms and studied egg-laying rates after a single mating until the depletion of sperm, and the fitness of the resulting offspring. We found a higher sperm storage capability in BL, likely reflecting the different seasonal availability of HL and BL hosts. We also observed a notable variation in sperm function at the population level within lineages and significant differences in fecundity and offspring fitness between lineages. However, no difference in egg numbers or offspring fitness was observed between within- and between-lineage crosses. Differences in sperm storage or egg-laying rates between HL and BL that we found did not affect reproductive isolation. Neither did the population-specific variation in sperm function. Overall, our results show no post-copulatory reproductive isolation between the lineages. How genetic differentiation in sympatry is maintained in the absence of a post-copulatory barrier between BL and HL remains to be investigated.

Understanding how many mates an animal has in its lifetime is a critical factor in sexual selection. At the same time, differences in an organism's ecology, such as the quantity and quality of food, could be reflected in different mating rates. Mating rate had a significant effect on female net fitness (i.e., lifetime offspring production), however, laboratory measurements cannot well mirror the situation in wild. The common bedbug (Cimex lectularius) is a well-established model for studying traumatic insemination and sexual conflict. The species comprises two host lineages that feed on bats (BL) or humans (HL). HL can constantly feed on human hosts throughout the year, while BLs feed only during summer months when their bat hosts occupy the roosts. Because mating in female bedbugs is closely linked to foraging, this system provides a valuable model to study mating variation in the field. We established a new method for estimating age-dependent mating rates of females in the wild by relating the fluorescent pigment accumulation in the eyes of females to the number of mating scars that manifest as melanized spots caused by the injection of sperm through the wall of the female abdomen by the male into the spermalege. In addition, using laboratory bedbugs we found that three and a half observed matings on average lead to one observed melanized mating scar. Although young BL and HL females (with low pteridine concentrations) did not differ in the number of matings, the mating rate increased with age only in HL but not in BL females. We sampled on average older BL than HL females. The lack of access to food (bat blood) during winter could explain the lack of increase in the number of scars with age in BL. In species where mating leaves visible marks, using fluorescent pigments to determine female age (applicable to most arthropods) could be an important tool to study sexual selection and mating rate in the wild. The method can help formulate sustainable and biologically lucid approaches for their control.

Global change has manifested itself as climate warming in Central Europe in recent decades. Average daily air temperatures increased by an average of 2 °C between 1982 and 2018. Air temperature changes have affected the timing of the vegetation periods (phenophases) and have also influenced the behaviour of animals. We worked with data on wildlife-vehicle crashes (WVC) recorded by the Czech Police in the period 1982–2019. Three peaks can usually be observed (spring, summer, and autumn) in the WVC time series. Eighty percent of these records involved roe deer ( Capreolus capreolus ). Such a high ratio allowed us to assume that any significant changes detected in WVC will be predominantly related to roe deer. We discovered that roe deer mortality on roads occurs earlier at present in the spring than in the past. The spring peak has shifted almost a month to the beginning of the year compared to the situation 38 years ago. The changes in the respective summer and autumn peaks were not statistically significant. The results suggest the effect of climate change on roe deer behaviour through increasing air temperatures and shifting vegetation phenophases. Thus, an earlier onset of deer activity associated with territory delineation and expected higher movement activity can be indirectly determined by the analysis of the WVC time series. The observed shift in the spring WVC peak in the roe deer model reveals a shift in ungulate behavioural patterns that is not evident from other biological data and thus surprisingly offers a suitable study framework for determining the impacts of environmental change on animals.

High number of moth species are considered to be agricultural pests in their caterpillar stage. Birds and other arthropods often forage moths, but ecosystem services provided by temperate bats are just coming to light in past few years. Although there is no doubt that insectivorous bats forage upon adult stages of pest moths contributing to the quality and quantity of crops, it remains unclear how many prey items have foraged and therefore it is unclear if the amounts taken are sufficient for biocontrol. Molecular detection of pest moth imagoes in bat diet is a relatively new approach that only delivers present or absent data. Therefore, sorting contains of bat faeces using morphological size determination may lead to better prey quantification. As the number of consumed prey items determines the boundary between consumption and regulatory significance, we focused on (i) if indigestible moth body parts retrieved from faeces reflect the number of moths eaten, (ii) how size of indigestible moth body parts relates to the overall moth body size, and (iii) an accuracy of moth classification into size groups. Our results indicated that base frenulum (hook holding front and hinder wings together) width is the most suitable characteristic to determine body size of the moth, with a discrimination success exceeding 73% when placing the moth into one of four size categories. The size differentiation of prey within a faecal sample together with molecular identification and other semiquantitative methods allows for more precise quantification and could yet help confirm the importance of bats as biological control agents.

Naše společnost je neustále v pohybu a silniční doprava je jednou z nejrozšířenějších lidských činností posledních let. V důsledku pohybu dopravních prostředků však dochází k mnoha nepříjemným střetům, mezi vozidly samotnými, ale také s volně žijícími živočichy. Silnice v celosvětovém měřítku totiž často přetínají trasy přirozeného pohybu zvířat, která potom nemají jinou možnost, než se je pokoušet překonávat. V naprosté většině případů jsou odkázána pouze na své smysly a instinkty, aby se bezpečně dostala na opačnou stranu komunikace. Jedná se však o velmi riskantní počínání a následkem těchto kolizí hynou miliony živočichů denně. Jak významným problémem pro člověka střety se zvířaty vůbec jsou? Kdy a kde ke střetům dochází nejčastěji? Jaké jsou následky střetů pro posádky vozidel? Kde končí a k čemu jsou dále využívána těla uhynulých zvířat? Jaká existují řešení tohoto problému? Odpovědi najdete uvnitř této knihy.

Kidney samples from 300 bat cadavers from the Czech and Slovak Republics were tested for Leptospira DNA using PCR and sequencing of three genes (lipL32, flab, and 16S ribosomal RNA). Overall detection rate was 4.7% and two bat species (Myotis myotis and Nyctalus noctula) were PCR-positive for at least one gene. Detected Leptospira sequences were similar to L. interrogans and L. borgpetersenii, and included a potentially novel species related to L. weilii.

Rivers are generally considered critical habitats for biodiversity; however, this often ignores the fact that many rivers may run dry and support terrestrial as well as aquatic fauna. Here, we investigated the ecological value of intermittent rivers for terrestrial vertebrates by installing camera traps along rivers subject to varying dry periods in two contrasting European climatic zones. We then analysed i) species presence and behaviours (as a proxy of ecological functions) on perennial and intermittent streams; ii) environmental (hydrological and geomorphological) and anthropogenic factors affecting the frequency of occurrence and number of species recorded; and iii) the importance of hydrological factors as regards ecological functioning. In both study areas, we recorded a higher number of species and individuals along intermittent streams than perennial streams, with highest values in intermittent reaches exhibiting shorter dry periods. Both abundance and species richness were strongly affected by hydrological factors in both study areas, including not only the occurrence but also the duration of the dry period. Dry channels played a key role as migration corridors and as a source of food, being used more frequently than riparian habitats when the river ran dry. Our findings indicate that terrestrial vertebrate fauna benefit from dry phases in rivers. Intermittent rivers, supporting a high abundance and diversity of fauna, should be considered as target ecosystems for wildlife conservation. Not doing so will jeopardise urgently needed conservation strategies in the face of accelerating global climate change.

The challenges of surviving periods of increased physiological stress elicit selective pressures that drive adaptations to overcome hardships. Bats in the Palearctic region survive winter in hibernation. We sampled single nucleotide polymorphisms (SNPs) in hibernating Myotis myotis bats using double-digest restriction site-associated DNA sequencing and we associated the genomic variability with the observed phenotypes reflecting hibernation site preference, body condition and bat health during hibernation. We did not observe genotype associations between the detrended body condition index, representing fat reserves, and functional genes involved in fat metabolism. Bat body surface temperature, reflecting roost selection, or roost warmth relative to the climate at the site did not show any associations with the sampled genotypes. We found SNPs with associations to macroclimatic variables, characterising the hibernaculum, and blood biochemistry, related to health of the bat. The genes in proximity of the associated SNPs were involved in metabolism, immune response and signal transduction, including chaperones, apoptosis and autophagy regulators and immune signalling molecules. The genetic adaptations included adaptation to tissue repair and protection against tissue damage.

Moths (Lepidoptera) are major agricultural and forest pests in many parts of the world, including Europe, with many causing great economic damage to crops, horticultural plants, stored items, and wool products. Here, we focus on two ecologically similar inchworms, Operophtera brumata and Erannis defoliaria , known for their high foliage consumption during the spring emergence of caterpillars. We hypothesise that bats could play a role in reducing pests such as caterpillars by switching to this abundant emerging prey. At two infested and one control forest sites, caterpillars were sampled during spring to determine levels of infestation. At the same time, bat flight activity was monitored during the peak in caterpillar abundance. During the spring caterpillar outbreak, we collected faecal samples of forest-dwelling bats capable of using gleaning. The majority of samples were positive for our focus species, being 51.85% for O. brumata and 29.63% for E. defoliaria faecal samples. The foraging activity of two gleaning bats, Myotis nattereri and Myotis bechsteinii , increased at both infested sites, but not at the control site, during caterpillar emergence, as did foraging of Plecotus auritus/austriacus , which used both gleaning and aerial hawking. We conclude that both specialists and occasional gleaners, which prefer different prey but are able to switch their foraging strategies, aggregate at sites during pest emergence and, as such, our results confirm the high potential of bats to reduce numbers of pest species such as caterpillars.