Bat Species Research Articles

Conservation gaps for Brazilian bats, limited protection across conservation units and the importance of the indigenous lands.

In Brazil, there is 13% of the world's bat diversity, is the second most diverse group of mammals, playing a crucial role in providing ecosystem services that benefit humans. However, anthropogenic disturbances exacerbate processes of species extinction, shifts in geographic distributions, and phenological changes, despite efforts to safeguard biodiversity through the creation of Conservation Units and Indigenous Lands. Moreover, gaps in taxonomic knowledge and challenges related to species distribution hinder the effective implementation of conservation strategies in protected areas. This study assesses the contribution of Brazilian Conservation Units (both Full Protection and Sustainable Use) and Indigenous Lands to the conservation of bat species and their ecosystem services. It also presents maps illustrating species richness by trophic guilds and threat classification according to IUCN, including species listed as Data Deficient. The findings reveal low percentages of potential bat distribution areas within these protected regions, especially for insectivorous, nectarivorous, and frugivorous bats in the Cerrado biome, which are classified as Near Threatened. Additionally, the highest bat species richness was observed in the Amazon and Atlantic Forest biomes.

Bats as instructive animal models for studying longevity and aging.

Bats (order Chiroptera) are emerging as instructive animal models for aging studies. Unlike some common laboratory species, they meet a central criterion for aging studies: they live for a long time in the wild or in captivity, for 20, 30, and even >40 years. Healthy aging (i.e., healthspan) in bats has drawn attention to their potential to improve the lives of aging humans due to bat imperviousness to viral infections, apparent low rate of tumorigenesis, and unique ability to repair DNA. At the same time, bat longevity also permits the accumulation of age-associated systemic pathologies that can be examined in detail and manipulated, especially in captive animals. Research has uncovered additional and critical advantages of bats. In multiple ways, bats are better analogs to humans than are rodents. In this review, we highlight eight diverse areas of bat research with relevance to aging: genome sequencing, telomeres, and DNA repair; immunity and inflammation; hearing; menstruation and menopause; skeletal system and fragility; neurobiology and neurodegeneration; stem cells; and senescence and mortality. These examples demonstrate the broad relevance of the bat as an animal model and point to directions that are particularly important for human aging studies.

Response of phyllostomid bat diversity to tree cover types in North-western Ecuador

Agricultural activities affect tropical forest biodiversity; however, some bat species can survive under these anthropogenic changes. We described the characteristics of phyllostomid bat assemblages in tree covers located in 48 plots among four agricultural landscapes of North-western Ecuador. Bats were captured with mist nets installed at a ground level reaching three meters’ height. For each of the plots, we installed a mist net in four types of tree cover (polyspecific live fences, monospecific live fences, cacao plantations, and isolated trees in pastures). We captured 250 phyllostomid bats belonging to 16 species with a trapping effort of 19,200 m2 of net coverage. Polyspecific live fences showed significant differences in relative abundance, richness, and diversity of phyllostomid bats compared to the other three. Frugivorous and nectarivorous guilds were the most abundant, and also exhibited the highest richness among other guilds present in agricultural landscapes. In addition, frugivorous, and nectarivorous guilds increase their abundance and richness in agricultural landscapes, while the animalivorous guild is negatively affected. We recommend installing polyspecific live fences in tropical production systems to support the conservation of phyllostomid bats. We conclude that living fences composed of various plant species favour the abundance, richness, and diversity of phyllostomid bats.

Non-invasive monitoring of adrenocortical activity in the Gould’s wattled bat (Chalinolobus gouldii)

Although bats are the second most species-rich mammalian order, very little is known about their endocrine physiology. Glucocorticoids (GCs) are commonly associated with the stress response, but also modulate vital physiological functions which help animals adapt to their environment. Understanding normal patterns of adrenocortical activity can provide valuable insights into a species’ fitness. Non-invasive hormone monitoring via faecal samples provides an integrated measure of adrenocortical activity while minimising stress on the animal but must be properly validated to ensure reliable results. The goal of this study was to validate an enzyme immunoassay for monitoring faecal glucocorticoid metabolites (FGMs) in a common Australian insectivorous bat species, the Gould’s wattled bat (Chalinolobus gouldii). We compared the performance of five assays for monitoring changes in FGMs following capture and transfer of C.gouldii from the wild to captivity. Four of the five assays detected a significant increase in FGMs following capture, but the magnitude of the increase and consistency across individuals differed considerably. We selected the UVM-69a assay as the best performing assay to then describe normative patterns of adrenocortical activity in the species. Males had higher FGM levels than females, and juveniles had higher FGM levels than adults. Individuals with poorer body condition had higher FGM levels. We also demonstrate seasonal patterns of FGMs with higher levels in March and April corresponding with reproductive up-regulation and lower levels in May and November. Our study is the first of its kind to examine adrenocortical activity in an Australian insectivorous bat and provides a valuable tool for studying this species. Understanding adrenal function in common species such as C.gouldii can shed light on the physiological mechanisms facilitating survival and success in changing environments.

Acoustic study of urban bat diversity in Veliko Tarnovo, Bulgaria

Urbanisation presents both challenges and opportunities for bat populations. Understanding the composition and distribution of urban bat species is the first step toward their effective conservation. However, comprehensive studies on urban bat diversity remain scarce in Bulgaria. To address this gap, we conducted a year-long acoustic survey on five different habitats in the urbanised territory of Veliko Tarnovo. Our study identified the presence of eight bat species and other distinct acoustic groups within the urban environment. Bats were found to utilise various habitats across the urban landscape. Although the activity was highest during May and September, bats remained active all year round, including the winter. Our study provides insights into synanthropic bats’ seasonal and microhabitat-dependent use of urban areas. These findings will establish a baseline for future research focusing on habitat preferences, population dynamics, and interactions with urbanisation. Such research is essential for the effective management and conservation of bat populations in urban environments.

High Resource Overlap and a Consistently Generalised Pattern of Interactions in a Bat-Flower Network in a Seasonally Dry Landscape.

Pollination is an ecosystem process that is crucial to maintain biodiversity and ecosystem function. Bats are important pollinators in the tropics and are an integral part of complex plant-pollinator interaction networks. However, network analysis-based approaches are still scarce at the plant species and bat community levels. We used metabarcoding to identify plant taxa present in pollen from fur and faecal samples collected across 1 year from three nectar-feeding bat roosts in central Mexico. We calculated the frequency of occurrence of plant taxa and assembled a zoocentric network of bat-plant interactions. We constructed a year-long network, encompassing the entire period of sampling, two seasonal networks comprising the wet and dry seasons, and six individual networks from sampling at two-month intervals across the year. Four species of nectar-feeding bats interacted with 36 plant species from 16 families. We found highly generalised interaction patterns across networks corresponding with opportunistic feeding behaviour by bats, with little seasonal variation in network structure. There was high resource overlap between bat species, and bats visited a diverse range of plant species even during periods with a high abundance of particular resources in the landscape. The diverse diet of nectar-feeding bats emphasises the importance of floristically rich natural habitats in the landscape to provide reliable foraging resources year-round in a seasonally variable system. While a generalised network structure is thought to increase robustness, further research is necessary to understand how fluctuations in pollinator abundance and diversity in the face of land use and climate change may impact bat-flower networks and the consequences to plant communities.

Maximizing benefits to bat populations through management of power line corridors

Abstract Power line corridors are ubiquitous worldwide and are commonly used by bats as habitat. Targeted management of these corridor habitats has the potential to aid bat populations, which is critically important given the multifaceted threats facing bat species, including the emerging infectious disease white‐nose syndrome (WNS) in North America. Here, we review known and potential impacts of management of existing power line corridors on three bat behaviours: foraging, roosting and commuting. We also identify bats in the United States that would benefit from changes to management of power line corridors for improvements to roosting and foraging habitats, particularly species of conservation concern that roost and forage along forest edges. Key recommendations are to avoid disturbance to roosting bats when maintaining vegetation along power line corridors, apply integrated vegetation management to maximize native plant diversity to improve prey options for bats and apply targeted interventions (e.g. artificial roost creation, creation of ponds) in a well‐justified ecological context. Practical implication. We highlight high‐priority research topics to fill knowledge gaps, including testing whether vegetation management treatments targeting plant and insect communities increase bat fitness and cause positive population‐level responses in focal bat species. We conclude that building evidence on how bats are affected by power line corridor management is a conservation need.

Non-invasive biomarkers for investigating urban metal exposure in neotropical bats

In urban centers, sewage treatment plants (STPs) serve as foraging and shelter areas for bats; however, they are sources of persistent pollutants that affect the health of these animals. This study aimed to investigate the impact of pollutants from an STP on the health of different species of neotropical bats from different guilds using non-invasive biomarkers. A conservation unit, the Silvania National Forest (SNF), was used as a reference area for comparison purposes. Blood, buccal mucosa, and fur samples were obtained for comet assay, micronucleus test, leukocyte profile, and metal concentration analysis in fur. Our results demonstrated that bats collected at the STP show a higher frequency of genotoxic damage, nuclear abnormalities, and an inflammatory response linked to infection than bats from the SNF. Regarding guilds, frugivores and nectarivores showed more pronounced responses to damage, but insectivores bats also showed relevant responses. While STPs are considered a source of pollutants, other urban sources of contamination likely contributed to these results. Still we encourage further studies using other non-invasive biomarkers, detection analysis of different pollutants in biological matrices, and the use of other wildlife species inserted in urban centers.

Seed dispersal by bats (Chiroptera: Phyllostomidae) and mutualistic networks in a landscape dominated by cocoa in the Brazilian amazon

Bats play essential roles in neotropical ecosystems, performing crucial ecological functions such as insect pest control, pollination of plants with significant economic, social, and ecological value, and seed dispersal, including that of pioneer plant species. These animals are directly linked to human well-being, and declines in their populations can even have adverse effects, such as increasing the need for pesticides in regions where natural insect control is reduced. The seed dispersal conducted by bats is fundamental for maintaining neotropical biodiversity, as it supports habitat regeneration and the propagation of various plant species. Moreover, the role of these dispersers is enhanced due to their ability to inhabit a variety of environments, from natural forests to anthropized areas. However, the conversion of natural forests into agricultural production areas, as well as urbanization, has affected the structure of mutualistic networks between bats and plants. In this context, the objective of this study was to identify the pattern of seed dispersal by bats of the Phyllostomidae family in an anthropized landscape of the Brazilian Amazon. Data collection was conducted in different areas of natural forest, cocoa cultivation, and urban areas in the municipalities of the States of Pará. Regarding the results, the most representative subfamilies of bats were Carollinae (72.15%) and Stenodermatinae (21.8%). The botanical families Piperaceae (35.52%) and Solanaceae (19.71%) were the ones most preferred by the bats. Regarding species richness, the general bat-plant interaction network included 15 botanical families and 26 species of bats. The general interaction network was nested (WNODF= 29.8), with low Specialization (H2=0.27), Connectance (0.17), and Modularity corresponding to M=0.21. Thus, we highlight the importance of these species for the restoration of degraded environments. Therefore, through the execution of projects that demonstrate the importance of chiropterochory in the restoration of degraded ecosystems in the Amazon, it will be possible to create measures and subsidies focused on the conservation of bat and plant species that play a role in maintaining the planet's biodiversity.

Matched power-frequency-modulated signal transform and its application in bat call signal analysis.

Bat call signal analysis is an important research topic, which is meaningful for bat species identification, and the design of various biomimetic systems. In addition to the commonly used methods in the time-frequency domain, the fractional Fourier transform (FRFT) is a valuable signal processing tool, as it is a generalization of the Fourier transform. However, the FRFT is constrained to the analysis of the linear frequency modulated-like bat call signal, while the modulation of the harmonics in a bat call is often nonlinear. For this reason, this paper proposes an integral transform, named matched power-frequency-modulated (PFM) signal transform (MPST), which is also the generalization of the Fourier transform, more precisely, a time-warping Fourier transform. As with the limitation of FRFT, the MPST is constrained to the analysis of the PFM-like bat call with the instantaneous frequency defined as an approximate power function abut time, in which the power can be an arbitrary positive integer or a fraction. The applications of MPST on the PFM-modeled bat call analysis are mainly parameter estimation and harmonic separation, and the performance is fully validated using the recordings of the feeding buzzes, social calls, and distress calls from the European bats.

Anthropogenic impacts drive habitat suitability in South Asian bats

AbstractDespite their diversity and importance as ecological indicators and ecosystem service providers, the macroecology of bats in South Asia is poorly understood, and until recently studies on the ecological niches of these species have been rare. This study analyses the ecogeographic predictors of habitat suitability in South Asian bats by conducting ensemble ecological niche modelling using four algorithms (random forests, artificial neural networks, multivariate adaptive regression splines, and maximum entropy) to define suitability envelopes for 48 selected bat species, based on topographic, hydrographic, land-use, land-cover, and other anthropogenic impact factors. Anthropogenic impact variables showed high importance with Median Night-time Light being the biggest driver of habitat suitability for most of the study species with generally lower suitability of brighter areas. Projected suitable areas for individual species covered between 6.28% and 22.98% of the study area. Regions such as the Thar desert of northwestern India were consistently identified to have low suitability. The Western Ghats in India, the Himalayas in Bhutan, northern India, and Nepal, and Sri Lanka were identified as suitability hotspots for more than half the studied species overlapping with human-impacted habitats. This study offers insight into the impacts of anthropogenic pressure on the macroecology of bats in a megadiverse region and stresses the importance of analysing ecogeographic effects on ecological niches and habitat suitability, which can be vital to inform conservation planning and policymaking in the future.

Clinical and epidemiological investigation of human infection with zoonotic parasite Trypanosoma dionisii in China

BackgroundTrypanosomiasis continue to pose a global threat to human health, with human infection mainly caused by Trypanosoma brucei and Trypanosoma cruzi. MethodsWe present a 30-year-old pregnant woman with persistent high fever from Shandong Province, China. High-throughput sequencing revealed the presence of Trypanosoma dionisii in blood. We conducted an analysis of the patient’s clinical, epidemiological, and virological data. ResultsThe patients exhibited fever, shortness of breath, chest tightness, accompanied by change in liver function and inflammatory response. She made a full recovery without any long-term effects. T. dionisii was detected in blood collected 23 days after onset of illness. The 18S rRNA gene sequence showed close similarity to T. dionisii found in bats from Japan, while the gGAPDH gene was closely related to T. dionisii from bats in Mengyin County, Shandong Province. Phylogenetic analysis demonstrated the current T. dionisii belongs to clade B within its species group. Positive anti-Trypanosoma IgG antibody was detected from the patient on Day 23, 66 and 122 after disease onset, as well as the cord blood and serum from the newborn. Retrospective screening of wild small mammals captured from Shandong Province revealed a prevalence rate of 0.54% (7/1304) for T. dionisii; specifically among 0.81% (5/620) of Apodemus agrarius, and 0.46% (2/438) of Mus musculus. ConclusionsThe confirmation of human infection with T. dionisii underscores its potential as a zoonotic pathogen, while the widespread presence of this parasite in rodent and bat species emphasizes the emerging threat it poses to human health.

First records of three species of Lasiurus Gray, 1831 (Chiroptera, Vespertilionidae) in Bolivia

Insectivorous bats of the family Vespertilionidae have been grouped into eight tribes, with Lasiurini showing an extensive distribution in South America. In Bolivia, three species of lasiurine bats have been reported: Lasiurus blossevillii (Lesson & Garnot, 1826), L. ega (Gervais, 1856), and L. villosissimus (É. Geoffroy St.-Hilaire, 1806). The morphological analyses of specimens of this genus deposited in Bolivian scientific collections and comparisons with specimens from other countries (including holotypes) prompt us to report the first records of three species: Lasiurus atratus Handley 1996, L. castaneus Handley 1960, and L. egregius (Peters, 1870) in Bolivia, expanding their known geographic ranges to the southwestern part of the Amazon.

Is the general threatened status of four mammal groups affected by taxonomic changes over time?

The geographic range is a critical factor in assessing species’ threatened status on the IUCN Red List. A smaller geographic range increases the likelihood of a species being classified as threatened. Taxonomic revisions, which can split a widely distributed taxon into multiple smaller-range species, may elevate the threatened status for these newly recognized species. While taxonomic splitting is thought to increase the perceived threatened status of species, data on birds suggest the opposite, with newly recognized species being less threatened. No similar analysis has been conducted for mammals until now. This study compares the relationship between the number of recognized and threatened species in four mammalian orders (Carnivora, Cetartiodactyla, Chiroptera, and Rodentia) between 2005 and 2022. It was found that increases in species numbers due to taxonomic revisions correlated with increases in threatened species, particularly in Primates and Cetartiodactyla. The overall threatened status of these groups changed over time, with Primates and Cetartiodactyla becoming more threatened, while Rodentia became less threatened. We emphasize the need for consistent criteria in IUCN assessments to avoid biases, and we recommend that changes in the threatened status should only occur with robust evidence.

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).

HUMAN PATHOGENS AMONG BATS

Bats are known to inhabit both caves and open space areas. Bulgaria is among the Еuropean countries with the highest number of bat species. The species found in the country are distributed over a wide area. They range from the Pyrenees and the British Isles to the Pacific region and the Far East. Many bat species are carriers of potential human pathogens. Bats play an important role in agriculture and act as a biological pest crop control agent. Bulgarian bat ecosystem comprises temperate climate and a wide range of abiotic factors, including humidity, darkness, sunlight, and temperature variations. The metabolism of bats and their body temperature vary significantly between the period of activity and the hibernation. Fluctuations in body temperature can potentially impact host microbiome biodiversity. Temperature variations may induce a high level of microbial mutagenesis. Additionally,the existence in large, mixed-species colonies, togeteher with a relatively long individual lifespan (4 – 16 years) and extensive travel distances, enhances the likelihood of encountering multiple pathogens in a single host organism. This, in turn, facilitates genetic variations and re-combinations among those microbial pathogens, thereby raising their potential to breach species barriers. In this review, we summarized and analyzed the available scientific information concerning the potential microbial human pathogens associated with bats, alongside with our preliminary data on the biodiversity of bats blood microbiome. Future research should focus on bats as both pathogens carriers and dynamic models for predicting emerging and re-emerging zoonotic diseases.

Torpor energetics are related to the interaction between body mass and climate in bats of the family Vespertilionidae.

Torpor is an adaptive strategy allowing heterothermic animals to cope with energy limitations. In birds and mammals, intrinsic and extrinsic factors, such as body mass and ambient temperature, are the main variables influencing torpor use. Speakman and Thomas (2003) proposed a theoretical model of the relationship between the metabolic rate during torpor and the ambient temperature. Nevertheless, no empirical attempts have been made to assess the model predictions under different climates. Using open-flow respirometry, we evaluated the ambient temperature at which bats entered torpor and when torpid metabolic rate reached its minimum, the reduction in metabolic rate below basal values, and minimum torpid metabolic rate in 11 bat species of the family Vespertilionidae with different body mass from warm and cold climates. We included data on the minimum torpid metabolic rate of five species we retrieved from the literature. We tested the effects using mixed-effect phylogenetic models. All models showed a significant interaction between body mass and climate. Smaller bats went into torpor and reached minimum torpid metabolic rates at warmer temperatures, showed a higher reduction in the metabolic rate below basal values, and presented lower torpid metabolic rates than larger ones. The slopes of the models were different for bats from different climates. These results are likely explained by differences in body mass and the metabolic rate of bats, which may favor larger bats expressing torpor in colder sites and smaller bats in the warmer ones. Further studies to assess torpor use in bats of different climates are proposed.

Systematics of the Rhinolophus landeri complex, with evidence for 3 additional Afrotropical bat species

Abstract Roughly a third of all horseshoe bat species (Rhinolophidae: Rhinolophus) are found in Africa, where a recent continent-wide genetic survey suggested the presence of both undescribed and apparently invalid species. Here, we focus on the R. landeri species complex and the recent elevation of R. lobatus Peters, 1852, to species rank. That action created ambiguity in the taxonomy of East African members of the group—are both R. landeri Martin, 1838, and R. lobatus sympatric in East Africa or is another, unnamed species present there? Here, we refine genetic, morphological, and behavioral characterizations of R. landeri and its erstwhile synonyms with samples from the vicinity of their type localities. The distribution of R. landeri appears to be limited to Central and West Africa; existing genetic records attributed to this species from Mali clearly represent another taxon. We marshal genetic evidence for the species-level distinction of R. dobsoni Thomas, 1904, from Sudan, which was previously considered a synonym of R. landeri. We reject R. axillaris J. A. Allen, 1917, as a synonym of the R. landeri complex, provisionally regarding it as a valid member of the landeri species group. Finally, we demonstrate that East Africa is home to a fourth species of the landeri complex that is named herein. Final resolution of the systematics of this species complex awaits expanded characterizations (especially of genetics, vocalizations, and noseleaves) and studies of variation in regions of contact.

Cave Myotis (Myotis velifer) consume diverse prey items and provide important ecosystem services

Abstract Insectivorous bats play an essential role as predators in natural ecosystems and contribute to pest control in agricultural landscapes. However, characterizing diets of specific bat species is difficult using conventional methods that cannot capture detailed dietary information. In this study, we used metabarcoding of the cytochrome oxidase I mitochondrial gene to analyze fecal samples of Myotis velifer and provide insight into the seasonal variation of diet from a colony located in the Chihuahuan Desert region of Texas. After filtering sequence reads, we recovered and analyzed 706 molecular operational taxonomic units (MOTUs) in the diet of M. velifer. We found 484 taxa (species and genus level) belonging to 11 insect orders in 66 fecal samples collected from March to October 2021. The orders containing the most MOTUs were Diptera (n = 353), Lepidoptera (n = 160), and Blattodea (n = 59). In their diet, we identified important insect crop pests, non-native insects, and substantial consumption of mosquitoes. Dietary composition shifted throughout seasons. Bats captured in summer months consumed the highest diversity of arthropod orders, and those captured in the spring consumed more diet items but were less diverse in arthropod orders. Our results uncovered 2 additional orders consumed by M. velifer, Blattodea and Odonata, that have not been previously described in their diet.

Predation of Natalus macrourus (Chiroptera: Natalidae) by Trachops cirrhosus (Chiroptera: Phyllostomidae) in a ferriferous Brazilian Amazon cave

Abstract Trachops cirrhosus bats are especially notable for feeding on various types of preys throughout its range, including other bat species. Here we report predation events of T. cirrhosus on Natalus macrourus, a new bat species among a wide range of prey.