The Egyptian Rousette Genome Reveals Unexpected Features of Bat Antiviral Immunity.

Bats harbor many viruses asymptomatically, including several notorious for causing extreme virulence in humans. To identify differences between antiviral mechanisms in humans and bats, we sequenced, assembled, and analyzed the genome of Rousettus aegyptiacus, a natural reservoir of Marburg virus and the only known reservoir for any filovirus. We found an expanded and diversified KLRC/KLRD family of natural killer cell receptors, MHC class I genes, and type I interferons, which dramatically differ from their functional counterparts in other mammals. Such concerted evolution of key components of bat immunity is strongly suggestive of novel modes of antiviral defense. An evaluation of the theoretical function of these genes suggests that an inhibitory immune state may exist in bats. Based on our findings, we hypothesize that tolerance of viral infection, rather than enhanced potency of antiviral defenses, may be a key mechanism by which bats asymptomatically host viruses that are pathogenic in humans.

Single-cell transcriptome analysis of the in vivo response to viral infection in the cave nectar bat Eonycteris spelaea.

Bats are reservoir hosts of many zoonotic viruses with pandemic potential. We utilized single-cell transcriptome sequencing (scRNA-seq) to analyze the immune response in bat lungs upon in vivo infection with a double-stranded RNA virus, Pteropine orthoreovirus PRV3M. Bat neutrophils were distinguished by high basal IDO1 expression. NK cells and T cells were the most abundant immune cells in lung tissue. Three distinct CD8+ effector T cell populations could be delineated by differential expression of KLRB1, GFRA2, and DPP4. Select NK and T clusters increased expression of genes involved in T cell activation and effector function early after viral infection. Alveolar macrophages and classical monocytes drove antiviral interferon signaling. Infection expanded a CSF1R+ population expressing collagen-like genes, which became the predominant myeloid cell type post-infection. This work uncovers features relevant to viral disease tolerance in bats, lays a foundation for future experimental work, and serves as a resource for comparative immunology studies.

Thermomechanical properties of bat and human red blood cells-Implications for hibernation.

Hibernation is a widespread and highly efficient mechanism to save energy in mammals. However, one major challenge of hibernation is maintaining blood circulation at low body temperatures, which strongly depends on the viscoelastic properties of red blood cells (RBCs). Here, we examined at physiologically relevant timescales the thermomechanical properties of hundreds of thousands of individual RBCs from the hibernating common noctule bat (Nyctalus noctula), the nonhibernating Egyptian fruit bat (Rousettus aegyptiacus), and humans (Homo sapiens). We exposed RBCs to temperatures encountered during normothermia and hibernation and found a significant increase in elasticity and viscosity with decreasing temperatures. Our data demonstrate that temperature adjustment of RBCs is mainly driven by membrane properties and not the cytosol while viscous dissipation in the membrane of both bat species exceeds the one in humans by a factor of 15. Finally, our results show that RBCs from both bat species reveal a transition to a more viscous-like state when temperature decreases. This process on a minute timescale has an effect size that is comparable with fluctuations in RBC viscoelasticity over the course of the year, implying that environmental factors, such as diets, have a lower impact on the capability of RBCs to respond to different temperatures than general physical properties of the cell membrane. In summary, our findings suggest membrane viscoelasticity as a promising target for identifying mechanisms that could be manipulated to ensure blood circulation at low body temperatures in humans, which may be one first step toward safe synthetic torpor in medicine and space flight.

Physical constraints on thermoregulation and flight drive morphological evolution in bats.

Body size and shape fundamentally determine organismal energy requirements by modulating heat and mass exchange with the environment and the costs of locomotion, thermoregulation, and maintenance. Ecologists have long used the physical linkage between morphology and energy balance to explain why the body size and shape of many organisms vary across climatic gradients, e.g., why larger endotherms are more common in colder regions. However, few modeling exercises have aimed at investigating this link from first principles. Body size evolution in bats contrasts with the patterns observed in other endotherms, probably because physical constraints on flight limit morphological adaptations. Here, we develop a biophysical model based on heat transfer and aerodynamic principles to investigate energy constraints on morphological evolution in bats. Our biophysical model predicts that the energy costs of thermoregulation and flight, respectively, impose upper and lower limits on the relationship of wing surface area to body mass (S-MR), giving rise to an optimal S-MR at which both energy costs are minimized. A comparative analysis of 278 species of bats supports the model's prediction that S-MR evolves toward an optimal shape and that the strength of selection is higher among species experiencing greater energy demands for thermoregulation in cold climates. Our study suggests that energy costs modulate the mode of morphological evolution in bats­hence shedding light on a long-standing debate over bats' conformity to ecogeographical patterns observed in other mammals­and offers a procedure for investigating complex macroecological patterns from first principles.

Advances in understanding bat infection dynamics across biological scales.

Over the past two decades, research on bat-associated microbes such as viruses, bacteria and fungi has dramatically increased. Here, we synthesize themes from a conference symposium focused on advances in the research of bats and their microbes, including physiological, immunological, ecological and epidemiological research that has improved our understanding of bat infection dynamics at multiple biological scales. We first present metrics for measuring individual bat responses to infection and challenges associated with using these metrics. We next discuss infection dynamics within bat populations of the same species, before introducing complexities that arise in multi-species communities of bats, humans and/or livestock. Finally, we outline critical gaps and opportunities for future interdisciplinary work on topics involving bats and their microbes.

Intestinal Tropism of a Betacoronavirus (Merbecovirus) in Nathusius's Pipistrelle Bat (Pipistrellus nathusii), Its Natural Host.

The emergence of several bat coronavirus-related disease outbreaks in human and domestic animals has fueled surveillance of coronaviruses in bats worldwide. However, little is known about how these viruses interact with their natural hosts. We demonstrate a Betacoronavirus (subgenus Merbecovirus), PN-ßCoV, in the intestine of its natural host, Nathusius's Pipistrelle Bat (Pipistrellus nathusii), by combining molecular and microscopy techniques. Eighty-eight P. nathusii bat carcasses were tested for PN-ßCoV RNA by RT-qPCR, of which 25 bats (28%) tested positive. PN-ßCoV RNA was more often detected in samples of the intestinal tract than in other sample types. In addition, viral RNA loads were higher in intestinal samples compared to other sample types, both on average and in each individual bat. In one bat, we demonstrated Merbecovirus antigen and PN-ßCoV RNA expression in intestinal epithelium and the underlying connective tissue using immunohistochemistry and in situ hybridization, respectively. These results indicate that PN-ßCoV has a tropism for the intestinal epithelium of its natural host, Nathusius's Pipistrelle Bat, and imply that the fecal-oral route is a possible route of transmission. IMPORTANCE Virtually all mammal species circulate coronaviruses. Most of these viruses will infect one host species; however, coronaviruses are known to include species that can infect multiple hosts, for example the well-known virus that caused a pandemic, SARS-CoV-2. Chiroptera (bats) include over 1,400 different species, which are expected to harbor a great variety of coronaviruses. However, we know very little about how any of these coronaviruses interact with their bat hosts; for example, we do not know their modes of transmissions, or which cells they infect. Thus, we have a limited understanding of coronavirus infections in this important host group. The significance of our study is that we learned that a bat coronavirus that occurs in a common bat species in Europe has a tropism for the intestines. This implies the fecal-oral route is a likely transmission route.

Functional comparisons of the virus sensor RIG-I from humans, the microbat Myotis daubentonii, and the megabat Rousettus aegyptiacus, and their response to SARS-CoV-2 infection.

IMPORTANCE: A common hypothesis holds that bats (order Chiroptera) are outstanding reservoirs for zoonotic viruses because of a special antiviral interferon (IFN) system. However, functional studies about key components of the bat IFN system are rare. RIG-I is a cellular sensor for viral RNA signatures that activates the antiviral signaling chain to induce IFN. We cloned and functionally characterized RIG-I genes from two species of the suborders Yangochiroptera and Yinpterochiroptera. The bat RIG-Is were conserved in their sequence and domain organization, and similar to human RIG-I in (i) mediating virus- and IFN-activated gene expression, (ii) antiviral signaling, (iii) temperature dependence, and (iv) recognition of RNA ligands. Moreover, RIG-I of Rousettus aegyptiacus (suborder Yinpterochiroptera) and of humans were found to recognize SARS-CoV-2 infection. Thus, members of both bat suborders encode RIG-Is that are comparable to their human counterpart. The ability of bats to harbor zoonotic viruses therefore seems due to other features.

Different species of Chiroptera: Immune cells and molecules.

The distinct composition and immune response characteristics of bats' innate and adaptive immune systems, which enable them to serve as host of numerous serious zoonotic viruses without falling ill, differ substantially from those of other mammals, it have garnered significant attention. In this article, we offer a systematic review of the names, attributes, and functions of innate and adaptive immune cells & molecules across different bat species. This includes descriptions of the differences shown by research between 71 bat species in 10 families, as well as comparisons between bats and other mammals. Studies of the immune cells & molecules of different bat species are necessary to understand the unique antiviral immunity of bats. By providing comprehensive information on these unique immune responses, it is hoped that new insights will be provided for the study of co-evolutionary dynamics between viruses and the bat immune system, as well as human antiviral immunity.

Phylogeography of horseshoe bat sarbecoviruses in Vietnam and neighbouring countries. Implications for the origins of SARS-CoV and SARS-CoV-2.

Previous studies on horseshoe bats (Rhinolophus spp.) have described many coronaviruses related to SARS-CoV (SARSCoVr) in China and only a few coronaviruses related to SARS-CoV-2 (SARSCoV2r) in Yunnan (southern China), Cambodia, Laos and Thailand. Here, we report the results of several field missions carried out in 2017, 2021 and 2022 across Vietnam during which 1218 horseshoe bats were sampled from 19 locations. Sarbecoviruses were detected in 11% of faecal RNA extracts, with much more positives among Rhinolophus thomasi (46%). We assembled 38 Sarbecovirus genomes, including 32 SARSCoVr, four SARSCoV2r, and two recombinants of SARSCoVr and SARSCoV2r (RecSar), one showing a Spike protein very similar to SARS-CoV-2. We detected a bat co-infected with four coronaviruses, including two sarbecoviruses. Our analyses revealed that Sarbecovirus genomes evolve in Vietnam under strong geographical and host constraints. First, we found evidence for a deep separation between viruses from northern Vietnam and those from central and southern Vietnam. Second, we detected only SARSCoVr in Rhinolophus thomasi, both SARSCoVr and SARSCoV2r in Rhinolophus affinis, and only RecSar in Rhinolophus pusillus captured close to the border with China. Third, the bias in favour of Uracil in synonymous third codon positions of SARSCoVr extracted from R. thomasi showed a negative correlation with latitudes. Our results also provided support for an emergence of SARS-CoV in horseshoe bats from northern Yunnan and emergence of SARS-CoV-2 in horseshoe bats from northern Indochina subtropical forests (southern Yunnan, northern Laos and north-western Vietnam).

Prenatal growth patterns of the upper jaw complex with implications for laryngeal echolocation in bats.

Craniofacial morphology is extremely diversified within bat phylogeny, however growth and development of the palate in bats remains unstudied. The formation of both midline and bilateral orofacial clefts in laryngeally echolocating bats, morphologically similar to the syndromic and non-syndromic cleft palate in humans, are not well understood. Developmental series of prenatal samples (n = 128) and adults (n = 10) of eight bat species (two pteropodids, four rhinolophoids, and two yangochiropterans), and two non-bat mammals (Mus musculus and Erinaceus amurensis), were CT-scanned and cranial bones forming the upper jaw complex were three-dimensionally visualised to assess whether differences in palate development can be observed across bat phylogeny. Volumetric data of bones composing the upper jaw complex were measured to quantify palate growth. The premaxilla is relatively reduced in bats compared to other mammals and its shape is heterogeneous depending on the presence and type of orofacial cleft across bat phylogeny. The palatine process of premaxillary bones is lacking in pteropodids and yangochiropterans, whereas the premaxilla is a mobile structure which is only in contact caudally with the maxilla by a fibrous membrane or suture in rhinolophoids. In all bats, maxillary bones progressively extend caudally and palatine bones, in some cases split into three branches, extend caudally so that they are completely fused to another one medially prior to the birth. Ossification of the vomer and fusion of the maxillary and palatine bones occur earlier in rhinolophoids than in pteropodids and yangochiropterans. The vomer ossifies bilaterally from two different ossification centres in yangochiropterans, which is uncommon in other bats and non-bat mammals. Analysis of ontogenetic allometric trajectories of the upper jaw complex revealed faster development of maxillary, vomer, and palatine bones in yangochiropterans compared to other bats, especially rhinolophoids. Ancestral state reconstruction revealed that yangochiropterans have a higher magnitude of change in ossification rate compared to other bats and E. amurensis a lower magnitude compared to M. musculus and bats. This study provides new evidence of heterochronic shifts in craniofacial development and growth across bat phylogeny that can improve understanding of the developmental differences characterising nasal and oral emission strategies.

Shifts in population density centers of a hibernating mammal driven by conflicting effects of climate change and disease.

Populations wax and wane over time in response to an organism's interactions with abiotic and biotic forces. Numerous studies demonstrate that fluctuations in local populations can lead to shifts in relative population densities across the geographic range of a species over time. Fewer studies attempt to disentangle the causes of such shifts. Over four decades (1983-2022), we monitored populations of hibernating Indiana bats (Myotis sodalis) in two areas separated by ~110 km. The number of bats hibernating in the northern area increased from 1983 to 2011, while populations in the southern area remained relatively constant. We used simulation models and long-term weather data to demonstrate the duration of time bats must rely on stored fat during hibernation has decreased in both areas over that period, but at a faster rate in the northern area. Likewise, increasing autumn and spring temperatures shortened the periods of sporadic prey (flying insect) availability at the beginning and end of hibernation. Climate change thus increased the viability of northern hibernacula for an increasing number of bats by decreasing energetic costs of hibernation. Then in 2011, white-nose syndrome (WNS), a disease of hibernating bats that increases energetic costs of hibernation, was detected in the area. From 2011 to 2022, the population rapidly decreased in the northern area and increased in the southern area, completely reversing the northerly shift in population densities associated with climate change. Energy balance during hibernation is the singular link explaining the northerly shift under a changing climate and the southerly shift in response to a novel disease. Continued population persistence suggests that bats may mitigate many impacts of WNS by hibernating farther south, where insects are available longer each year.

Southern Africa's Great Escarpment as an amphitheater of climate-driven diversification and a buffer against future climate change in bats.

Hosting 1460 plant and 126 vertebrate endemic species, the Great Escarpment (hereafter, Escarpment) forms a semi-circular "amphitheater" of mountains girdling southern Africa from arid west to temperate east. Since arid and temperate biota are usually studied separately, earlier studies overlooked the biogeographical importance of the Escarpment as a whole. Bats disperse more widely than other mammalian taxa, with related species and intraspecific lineages occupying both arid and temperate highlands of the Escarpment, providing an excellent model to address this knowledge gap. We investigated patterns of speciation and micro-endemism from modeled past, present, and future distributions in six clades of southern African bats from three families (Rhinolophidae, Cistugidae, and Vespertilionidae) having different crown ages (Pleistocene to Miocene) and biome affiliations (temperate to arid). We estimated mtDNA relaxed clock dates of key divergence events across the six clades in relation both to biogeographical features and patterns of phenotypic variation in crania, bacula and echolocation calls. In horseshoe bats (Rhinolophidae), both the western and eastern "arms" of the Escarpment have facilitated dispersals from the Afrotropics into southern Africa. Pleistocene and pre-Pleistocene "species pumps" and temperate refugia explained observed patterns of speciation, intraspecific divergence and, in two cases, mtDNA introgression. The Maloti-Drakensberg is a center of micro-endemism for bats, housing three newly described or undescribed species. Vicariance across biogeographic barriers gave rise to 29 micro-endemic species and intraspecific lineages whose distributions were congruent with those identified in other phytogeographic and zoogeographic studies. Although Köppen-Geiger climate models predict a widespread replacement of current temperate ecosystems in southern Africa by tropical or arid ecosystems by 2070-2100, future climate Maxent models for 13 bat species (all but one of those analyzed above) showed minimal range changes in temperate species from the eastern Escarpment by 2070, possibly due to the buffering effect of mountains to climate change.

Bat consumption by holostean fishes in the Eocene Lake Messel: insights into the trophic adaptability of extinct gars and bowfins.

Direct evidence of trophic interactions between extinct species is rarely available in the fossil record. Here, we describe fish-mammal associations from the middle Eocene of Messel (Germany), consisting of three specimens of holosteans (one Atractosteus messelensis (Lepisosteidae) and two Cyclurus kehreri (Amiidae)) each preserved with a bat specimen (Palaeochiropteryx tupaiodon) lying in close contact with its jaws. This suggests that these fishes probably died after failed swallowing attempts, with the bat wing membrane entangled in their jaws resulting in a fatal handicap. Based on data from modern gars and bowfins, A. messelensis and C. kehreri may have opportunistically attacked drowning and dying individuals or scavenged on floating/sinking carcasses. This hypothesis is also supported by the unusually high number of bat specimens preserved in the deposits of the Eocene Lake Messel, suggesting that this group of small mammals may have represented a substantial food source for generalist feeders. This is the earliest case of chiropterophagy and the first known evidence of bat consumption by lepisosteid and amiid fishes, emphasizing the high trophic variability and adaptability of these groups throughout their evolutionary histories. The newly described associations provide important information for reconstructing the Eocene Lake Messel palaeoecosystem and its trophic web.

Optimally warm roost temperatures during lactation do not improve body condition in a long-lived bat.

Lactation is the most energetically demanding time in the life of female mammals. To maximize lifetime reproductive success, females of long-lived species, such as bats, face a trade-off between investing in current and future reproduction. However, it is unclear whether global warming could influence this trade-off through shifts in the energy budget: warmer temperatures may reduce thermoregulatory costs, leaving mothers with more energy available for maternal care or for improving their own body condition (BC), which may increase survival and ensure future reproduction. Here, we investigated whether lactating Bechstein's bats (Myotis bechsteinii) allocate the energy saved in optimally warm roosts into their own BC. We analysed a 14-year dataset on the individual BC of 237 females marked with radio-frequency identification tags from four wild maternity colonies. In two of the colonies, the temperature in the roosts, in which the females raised their offspring, was artificially kept in the bats' thermoneutral zone to reduce their thermoregulation costs. We found that BC shortly after the lactation period did not differ between mothers from heated and non-heated colonies. Our results suggest that mothers do not invest the energy saved in warmer roosts in their own BC, consistent with an increased investment in maternal care.

Vulnerability of Southern Hemisphere bats to white-nose syndrome based on global analysis of fungal host specificity and cave temperatures.

White-nose syndrome (WNS), a disease affecting hibernating bats, is caused by the fungal pathogen Pseudogymnoascus destructans (Pd). Since the initial introduction of Pd from Eurasia to the United States in 2006, WNS has killed millions of bats throughout the temperate parts of North America. There is concern that if Pd is accidentally introduced to the Southern Hemisphere, WNS could pose similar threats to the bat fauna of the Southern Hemisphere's more temperate regions. Efforts are required to better understand the vulnerability of bats globally to WNS. We examined phylogenetic distances among cave roosting bat species globally to estimate the probability of infection by Pd. We predicted cave thermal suitability for Pd for 441 cave-roosting bat species across the globe via spatial analysis. We used host specificity models based on 65 species tested for Pd to determine phylogenetic specificity of Pd. Phylogenetic distance was not an important predictor of Pd infection, confirming that Pd has low host specificity. We found extensive areas (i.e., South America, Africa, and Australia) in the Southern Hemisphere with caves that were suitable for cave-roosting bat species and for Pd growth. Hence, if Pd spreads to the Southern Hemisphere, the risk of exposure is widespread for cave-roosting bats, and infection is possible regardless of relatedness to infected species in the Northern Hemisphere. Predicting the consequences of infection remains difficult due to lack of species-specific information about bat winter biology. Nevertheless, WNS is an important threat to naive Southern Hemisphere bat populations. Hence, biosecurity measures and planning of management responses that can help prevent or minimize a potential WNS outbreak in the Southern Hemisphere are urgently needed.

Vulnerabilidad de los murciélagos del hemisferio sur ante el síndrome de nariz blanca con base en el análisis mundial de especificidad del hospedero fúngico y las temperaturas de las cuevas Resumen El síndrome de nariz blanca (SNB), una enfermedad que afecta a los murciélagos en hibernación es causado por el hongo patógeno Pseudogymnoascus destructans (Pd). Desde la introducción inicial del Pd desde Eurasia a Estados Unidos en 2006, el SNB ha matado a millones de murciélagos en las zonas templadas de Norteamérica. Existe la preocupación de que, si el Pd se introduce por accidente en el hemisferio sur, el SNB podría amenazar de forma similar a los murciélagos en las regiones más templadas de este hemisferio. Se requieren esfuerzos para comprender mejor la vulnerabilidad de los murciélagos ante el SNB a nivel mundial. Analizamos las distancias filogenéticas entre las especies de murciélagos de cuevas de todo el mundo para estimar la probabilidad de infección por Pd. Mediante un análisis espacial, predijimos la idoneidad térmica de las cuevas para el Pd en 441 especies de murciélagos de todo el mundo. Usamos modelos de especificidad de hospedero basados en 65 especies analizadas para determinar la especificidad filogenética de Pd. La distancia filogenética no fue un factor predictivo importante de la infección por Pd, lo que confirma que la especificidad de hospedero de Pd es baja. En el hemisferio sur encontramos amplias zonas (América del Sur, África y Australia) con cuevas adecuadas para especies de murciélagos que se refugian en cuevas y para el crecimiento de Pd. Por lo tanto, si Pd se propaga en el hemisferio sur, el riesgo de exposición es generalizado para los murciélagos que pernoctan en cuevas, y la infección es posible independientemente del parentesco con especies infectadas en el hemisferio norte. Sigue siendo difícil predecir las consecuencias de la infección debido a la falta de información específica sobre la biología invernal de los murciélagos. No obstante, el SNB es una amenaza importante para las poblaciones de murciélagos del hemisferio sur que no están preparadas para enfrentarla. Por ello se necesiten medidas urgentes de bioseguridad y planificación de respuestas de gestión que puedan ayudar a prevenir o minimizar un posible brote del SNB en el hemisferio sur.

Effective conservation of subterranean-roosting bats.

Bats frequently inhabit caves and other subterranean habitats and play a critical role in subterranean food webs. With escalating threats to subterranean ecosystems, identifying the most effective measures to protect subterranean-roosting bats is critical. We conducted a meta-analysis to evaluate the effectiveness of conservation and management interventions for subterranean-roosting bats. We used network analyses to determine to what extent interventions for bats overlap those used for other subterranean taxa. We conducted our analyses with data extracted from 345 papers recommending a total of 910 conservation interventions. Gating of roost entrances was applied to preserve bat populations in 21 studies, but its effectiveness was unclear. Habitat restoration and disturbance reduction positively affected bat populations and bat behavior, respectively, in ≤4 studies. Decontamination was assessed in 2 studies and positively affected bat populations, particularly in studies focused on reducing fungal spores associated with white-nose syndrome in North America. Monitoring of bat populations as an effective conservation strategy was unclear and infrequently tested. Only 4% of bat studies simultaneously considered other subterranean organisms. However, effective interventions for bat conservation had similarities with all other organisms. If other subterranean organisms are considered when applying interventions to conserve bats, they might also benefit.

Conservación eficiente de murciélagos subterráneos Resumen Es común que los murciélagos habiten en cuevas y otros hábitats subterráneos y contribuyan a las redes alimenticias bajo tierra. Ya que estos ecosistemas cada vez se enfrentan a más amenazas, es importante identificar las medidas más efectivas para proteger a los murciélagos subterráneos. Realizamos un metaanálisis para evaluar la eficiencia de la conservación y las intervenciones de manejo para estos mamíferos. Usamos un análisis de redes para determinar el grado al que las intervenciones en pro de los murciélagos se traslapan con aquellas usadas para otros taxones subterráneos. Realizamos nuestros análisis con datos extraídos de 345 artículos que recomendaban 910 intervenciones de conservación. Se aplicó la colocación de compuertas en la entrada de los dormideros para conservar la población de murciélagos en 21 estudios, pero no quedó clara su efectividad. La restauración del hábitat y la reducción de las perturbaciones afectaron, respectivamente, a las poblaciones y al comportamiento de los murciélagos en ≤ 4 cuatro estudios. Se evaluó a la desinfección en dos estudios y ésta tuvo un efecto positivo sobre las poblaciones, particularmente en los estudios enfocados en la reducción de esporas micóticas asociadas con el síndrome de nariz blanca en América del Norte. La eficiencia del monitoreo de las poblaciones de murciélagos como una estrategia de conservación no fue clara y casi nunca se evaluó. Sólo el 4% de los estudios sobre murciélagos consideró simultáneamente a otros organismos subterráneos. Sin embargo, las intervenciones eficientes para la conservación de murciélagos tuvieron similitudes con las de todos los demás organismos. Otros organismos pueden beneficiarse si se les considera cuando se aplican las intervenciones para conservar a los murciélagos.

Exploring the potential for online data sources to enhance species threat mapping through the case study of global bat exploitation.

Expanding digital data sources, including social media and online news, provide a low-cost way to examine human-nature interactions, such as wildlife exploitation. However, the extent to which using such data sources can expand or bias understanding of the distribution and intensity of threats has not been comprehensively assessed. To address this gap, we quantified the geographical and temporal distribution of online sources documenting the hunting and trapping, consumption, or trade of bats (Chiroptera) and compared these with the distribution of studies obtained from a systematic literature search and species listed as threatened by exploitation on the International Union for Conservation of Nature Red List. Online records were collected using automated searches of Facebook, Twitter, Google, and Bing and were filtered using machine classification. This yielded 953 relevant social media posts and web pages, encompassing 1099 unique records of bat exploitation from 84 countries. Although the number of records per country was significantly predicted by the number of academic studies per country, online records provided additional locations and more recent records of bat exploitation, including 22 countries not present in academic literature. This demonstrates the value of online resources in providing more complete geographical representation. However, confounding variables can bias the analysis of spatiotemporal trends. Online bat exploitation records showed peaks in 2020 and 2014, after accounting for increases in internet users through time. The second of these peaks could be attributed to the COVID-19 outbreak, and speculation about the role of bats in its epidemiology, rather than to true changes in exploitation. Overall, our results showed that data from online sources provide additional knowledge on the global extent of wildlife exploitation, which could be used to identify early warnings of emerging threats and pinpoint locations for further research.

Sondeo del potencial de las fuentes virtuales de datos para mejorar el mapeo de amenazas para las especies por medio del estudio de caso de la explotación mundial de murciélagos Resumen La expansión de las fuentes virtuales, incluidas las redes sociales y las noticias en línea, proporciona una forma asequible de analizar las interacciones entre el humano y la naturaleza, como la explotación de fauna. Sin embargo, no se ha analizado por completo el rango al que dichas fuentes pueden expandir o sesgar el conocimiento de la distribución e intensidad de las amenazas. Para abordar este vacío cuantificamos la distribución geográfica y temporal de las fuentes virtuales que documentan la caza, captura, consumo o mercado de murciélagos (Chiroptera) y las comparamos con la distribución de los estudios obtenidos de una búsqueda sistemática en la literatura y con las especies catalogadas como amenazadas por la explotación según la Lista Roja de la Unión Internacional para la Conservación de la Naturaleza. Recolectamos los registros virtuales por medio de búsquedas automatizadas en Facebook, Twitter, Google y Bing y después las filtramos con clasificaciones automatizadas. Esto arrojó 953 publicaciones relevantes en redes sociales y sitios web que englobaban 1099 registros únicos de la explotación de murciélagos en 84 países. Aunque pronosticamos de forma significativa el número de registros por país con el número de estudios académicos por país, los registros virtuales proporcionaron localidades adicionales y registros más recientes de la explotación de murciélagos, incluyendo a 22 países que no se encuentran en la literatura académica. Lo anterior demuestra el valor que tienen los recursos en línea para proporcionar una representación geográfica más completa. Sin embargo, las variables confusas pueden sesgar el análisis de las tendencias espaciotemporales. Los registros virtuales de la explotación de murciélagos mostraron picos en 2020 y en 2014, esto después de considerar el incremento de usuarios de internet con el tiempo. El segundo pico podría atribuirse al brote de COVID­19 y la especulación en torno al papel que tenían los murciélagos en su epidemiología y no tanto a un verdadero cambio en la explotación. En general, nuestros resultados mostraron que los datos de las fuentes virtuales proporcionan conocimiento adicional sobre el alcance mundial de la explotación de fauna, el cual podría usarse para identificar señales tempranas de amenazas emergentes y ubicar localidades para su mayor investigación.

Influence of microclimate and forest management on bat species faced with global change.

Climate refugia, areas where climate is expected to remain relatively stable, can offer a near-term safe haven for species sensitive to warming temperatures and drought. Understanding the influence of temperature, moisture, and disturbance on sensitive species is critical during this time of rapid climate change. Coastal habitats can serve as important refugia. Many of these areas consist of working forestlands, and there is a growing recognition that conservation efforts worldwide must consider the habitat value of working lands, in addition to protected areas, to effectively manage large landscapes that support biodiversity. The sensitivity of forest bats to climate and habitat disturbance makes them a useful indicator taxon. We tested how microclimate and forest management influence habitat use for 13 species of insectivorous bats in a large climate refugium in a global biodiversity hotspot. We examined whether bat activity during the summer dry season is greater in forests where coastal fog provides moisture and more stable temperatures across both protected mature stands and those regularly logged. Acoustic monitoring was conducted at a landscape scale with 20 study sites, and generalized linear mixed models were used to examine the influence of habitat variables. Six species were positively associated with warmer nighttime temperature, and 5 species had a negative relationship with humidity or a positive relationship with climatic moisture deficit. Our results suggest that these mammals may have greater climate adaptive capacity than expected, and, for now, that habitat use may be more related to optimal foraging conditions than to avoidance of warming temperatures and drought. We also determined that 12 of the 13 regionally present bat species were regularly detected in commercial timberland stands. Because forest bats are highly mobile, forage over long distances, and frequently change roosts, the stewardship of working forests must be addressed to protect these species.

Influencia del microclima y el manejo forestal sobre especies de murciélagos ante el cambio global Resumen Los refugios climáticos, áreas en donde se espera que el clima permanezca relativamente estable, pueden ofrecer un santuario a corto plazo para las especies sensibles al aumento de temperaturas y la sequía. Es muy importante entender la influencia de la temperatura, la humedad y las perturbaciones sobre las especies sensibles durante estos tiempos de cambio climático repentino. Los hábitats costeros pueden funcionar como refugios importantes. Muchas de estas áreas consisten en bosques funcionales y cada vez hay más reconocimiento de que los esfuerzos mundiales de conservación deben considerar el valor del hábitat de los suelos funcionales, además de las áreas protegidas, para manejar de manera efectiva los extensos paisajes que mantienen a la biodiversidad. La sensibilidad de los murciélagos de los bosques ante las perturbaciones climáticas y de hábitat hace que sean un taxón indicador útil. Analizamos cómo los microclimas y el manejo forestal influyen sobre el uso de hábitat de 13 especies de murciélagos insectívoros en un refugio climático amplio dentro de un punto caliente de biodiversidad mundial. Examinamos si la actividad de los murciélagos durante la temporada seca de verano es mayor en los bosques en donde la niebla costera proporciona humedad y temperaturas más estables tanto en los árboles maduros como aquellos que son talados con regularidad. Realizamos el monitoreo acústico a escala de paisaje en 20 estudios de sitio y usamos modelos lineales mixtos generalizados para examinar la influencia de las variables del hábitat. Seis especies estuvieron asociadas positivamente con la temperatura nocturna más cálida y cinco especies tuvieron una relación negativa con la humedad o una relación positiva con el déficit climático de humedad. Nuestros resultados sugieren que estos mamíferos pueden tener una mayor capacidad de adaptación climática de lo que se pensaba y, por ahora, que el uso de hábitat puede estar más relacionado con las condiciones óptimas de forrajeo que con la evasión de las temperaturas elevadas y la sequía. También determinamos que 12 de las 13 especies con presencia regional fueron detectadas con regularidad en los puntos de tala comercial. Ya que los murciélagos del bosque tienden a moverse mucho, forrajear a lo largo de grandes distancias y con frecuencia cambiar de nido, debemos abordar la administración de los bosques funcionales para proteger a estas especies.

Multiresidue analysis of bat guano using GC-MS/MS.

Bats are the second largest mammalian order and are an endangered species group with a strong need for contamination monitoring. To facilitate non-invasive monitoring of the ecological burden in bat populations, a multiresidue method for the simultaneous quantification of 119 analytes including pesticides, persistent organic pollutants (POPs), active pharmaceutical ingredients (APIs), polycyclic aromatic hydrocarbons (PAHs), UV blockers, plasticizers, and other emerging pollutants in bat guano with gas chromatography tandem mass spectrometry (GC-MS/MS) was developed. Sample preparation and clean-up were performed with a modified QuEChERS approach based on DIN EN 15662. The method uses 1.00 g bat guano as sample with acetonitrile and water for liquid-liquid extraction. Phase separation is assisted by citrate-buffered salting out agent. For clean-up of the extract, primary secondary amine (PSA) was combined with graphitized carbon black (GCB). The lower limits of quantification (LLOQ) ranged between 2.5 and 250 µg kg-1. Linearity was shown in a concentration range from the respective LLOQs to 1250 µg kg-1. The median of the mean recovery was 102.4%. Precision was tested at three concentrations. Method and injection precision were adequate with a relative standard deviation (RSD) below 20%. Furthermore, the comparative analysis with LC-MS/MS demonstrated the reliability of the results and provided a valuable extension of the analytical scope. As proof of concept, three guano samples from a German nursery roost of Myotis myotis were analysed. The results show a time-dependent change in contaminant concentration, highlighting the strong need for non-invasive contamination monitoring of whole bat populations.

Ectoparasite and bacterial population genetics and community structure indicate extent of bat movement across an island chain.

Few studies have examined the genetic population structure of vector-borne microparasites in wildlife, making it unclear how much these systems can reveal about the movement of their associated hosts. This study examined the complex host­vector­microbe interactions in a system of bats, wingless ectoparasitic bat flies (Nycteribiidae), vector-borne microparasitic bacteria (Bartonella) and bacterial endosymbionts of flies (Enterobacterales) across an island chain in the Gulf of Guinea, West Africa. Limited population structure was found in bat flies and Enterobacterales symbionts compared to that of their hosts. Significant isolation by distance was observed in the dissimilarity of Bartonella communities detected in flies from sampled populations of Eidolon helvum bats. These patterns indicate that, while genetic dispersal of bats between islands is limited, some non-reproductive movements may lead to the dispersal of ectoparasites and associated microbes. This study deepens our knowledge of the phylogeography of African fruit bats, their ectoparasites and associated bacteria. The results presented could inform models of pathogen transmission in these bat populations and increase our theoretical understanding of community ecology in host­microbe systems.