Urbanization is one of the main drivers of ecological change in the modern world. In most cases, species diversity in urban landscapes is lower than in natural ones; however, some groups of animals are able to exploit and benefit from urban habitat. Pipistrellus kuhlii s.l. is (P. k. lepidus according to recent taxonomic review), a common European urban bat, whose range has expanded on a wide scale in the last 40 years. Thought to originate in Central Asia, this species has extended its range throughout Eastern and Central and Europe (a distance of more than 2,500 km2) in part by using human settlements as a habitat. This study examines the ecological features of P. k. lepidus in wintertime in the Eastern part of Ukraine, where this species has been living for 20 years. Thirty-nine winter records of P. k. lepidus(1,301 individuals totally) were selected from the database of the Bat Rehabilitation Center of Feldman Ecopark, 19 of which were groups from 2 to 641 individuals. Pipistrellus k. lepidus was found in various types of structures, but most often in administrative buildings (school buildings - 69%). Records were usually obtained during renovation works (85%), and the roosting sites were cavities between the wooden planks of window frames and a wall (75%). The records were obtained in 26 settlements, from a village (0,293 kmand 252 people) to the biggest cities in the country (Kharkiv and Odessa). The sex ratio in winter aggregation in adults varied from 47% to 61% of females and for this-year individuals from 48% to 58%, respectively. The body mass at the end of the hibernation period (February/March) decreases for 17–20% compared to the beginning of the period (December). Adult females have bigger body size (body mass and forearm length) (p-value < 0.05). Our results showed that P. k. lepidus is capable of forming homogeneous, sedentary populations in all types of settlements in Ukraine for these twenty years. However, this choice of habitat means that the species faces a high mortality risk from humans during building renovation and insulation works or pest control actions.

Background Bats (Mammalia: Chiroptera) serve as natural reservoirs for many zoonotic pathogens worldwide, including vector-borne pathogens. However, bat-associated parasitic arthropods and their microbiota are thus far not thoroughly described in many regions across the globe, nor is their role in the spillover of pathogens to other vertebrate species well understood. Basic epidemiological research is needed to disentangle the complex ecological interactions among bats, their specific ectoparasites and microorganisms they harbor. Some countries, such as Ukraine, are particularly data-deficient in this respect as the ectoparasitic fauna is poorly documented there and has never been screened for the presence of medically important microorganisms. Therefore, the aims of this study were to provide first data on this topic. Methods A total of 239 arthropod specimens were collected from bats. They belonged to several major groups of external parasites, including soft ticks, fleas, and nycteribiid flies from six chiropteran species in Northeastern Ukraine. The ectoparasites were individually screened for the presence of DNA of Rickettsia spp., Anaplasma/Ehrlichia spp., Bartonella spp., Borrelia spp., and Babesia spp. with conventional PCRs. Positive samples were amplified at several loci, sequenced for species identification, and subjected to phylogenetic analysis. Results Rickettsia DNA was detected exclusively in specimens of the soft tick, Carios vespertilionis (7 out of 43 or 16.3%). Sequencing and phylogenetic analysis revealed high similarity to sequences from Rickettsia parkeri and several other Rickettsia species. Bacteria from the family Anaplasmataceae were detected in all groups of the ectoparasites (51%, 122/239 samples), belonging to the genera Anaplasma, Ehrlichia, and Wolbachia. The detection of Bartonella spp. was successful only in fleas (Nycteridopsylla eusarca) and bat flies (Nycteribia koleantii, N. pedicularia), representing 12.1% (29/239) of the collected ectoparasites. No DNA of Babesia or Borrelia species was identified in the samples. Conclusions We report for the first time in Ukraine the molecular detection of several bacterial agents in bat ectoparasites collected from six species of bats. The data presented extend the knowledge on the distribution of ectoparasite species in bats and their involvement in potentially circulating agents pathogenic for humans and vertebrate animals. Graphical Abstract

Bats are of high conservational status in most European countries. All bats are under legal protection in Ukraine and included in the national Red Data Book. However, bats remain one of the least studied groups of mammals in Ukraine. Their cryptic lifestyle limits the possibilities of direct observations and, as a result, data on bat distribution are incomplete. Wildlife rehabilitation centres accumulate a plethora of records of wild animals and those data may significantly contribute to knowledge on the species range, phenology and habitat preferences. This paper presents the data accumulated from over a decade of work by the Ukrainian Bat Rehabilitation Center (formerly The Bat Rehabilitation Center of Feldman Ecopark), the premier organisation engaged in the rescue and rehabilitation of bats across Ukraine. In addition to in-person data collected by Ukrainian Bat Rehabilitation Center staff, the Center also accepts observations of bat encounters from citizens. The Center’s dataset boasts over 20,000 distinct observations, which are the subject of this paper. This dataset, spanning 2011-2022, contains a total of 20,948 records of bat findings, 19,024 of which consist of records directly identified by UBRC team members. The remaining 1924 observations were provided by citizens through helpline. Data on 16 species and one subspecies have been collected. The highest number of records belongs to Nyctalus noctula (n = 15889), followed by Eptesicus serotinus (n = 2017) and Pipistrellus kuhlii lepidus (n = 2001). Less than 10% of these records have been previously published; the rest are presented in this paper for the first time. The dataset is particularly rich in information on bats in human settlements and is (to the best of the authors’ knowledge) the largest dataset on bats within human-modified landscapes ever collected from the territory of Eastern Europe. The entire dataset is available through the Global Biodiversity Information Facility (GBIF).