Vampire Bat Desmodus Rotundus Research Articles

Human cat borne rabies as the new epidemiology of the disease in the Andes mountains.

Rabies virus (RABV) is the etiologic agent of rabies, a fatal brain disease in mammals. Rabies circulation has historically involved the dog has the main source of human rabies worldwide. Nevertheless, in Colombia, cats (Felis catus) have become a relevant species in the epidemiology of rabies. To characterize rabies cases in humans in Colombia in the last three decades in the context of the epidemiology of the aggressor animal. We conducted a retrospective longitudinal epidemiological study of human rabies caused by cats' aggression, collecting primary and secondary information. Variables considered included the demography of the patient, symptoms, information about the aggressor animal as the source of infection and the viral variant identified. We found that the distribution of rabies incidence over the years has been constant in Colombia. Nevertheless, between 2003 and 2012 a peak of cases occurred in rural Colombia where cats were the most frequent aggressor animal reported. Most cats involved in aggression were unvaccinated against rabies. Cat's clinical signs at the time of the report of the human cases included hypersalivation and changes in behaviour. Human patients were mostly children and female and the exposure primarily corresponded to bite and puncture lacerations in hands. The RABV lineage detected in most cases corresponded to variant 3, linked to the common vampire bat (Desmodus rotundus). The geographical presentation of cat borne RABV in humans occurred along the Andes mountains, epidemiologically known as the rabies red Andean corridor. By finding cats as the primary source of rabies spillover transmission in Colombia, this report highlights the importance of revising national rabies control and prevention protocol in countries in the Andes region. Our results demonstrate that rabies vaccination for outdoor cats needs to prioritize to reduce the number of rabies-related human deaths.

Hierarchically embedded scales of movement shape the social networks of vampire bats.

Social structure can emerge from hierarchically embedded scales of movement, where movement at one scale is constrained within a larger scale (e.g. among branches, trees, forests). In most studies of animal social networks, some scales of movement are not observed, and the relative importance of the observed scales of movement is unclear. Here, we asked: how does individual variation in movement, at multiple nested spatial scales, influence each individual's social connectedness? Using existing data from common vampire bats (Desmodus rotundus), we created an agent-based model of how three nested scales of movement-among roosts, clusters and grooming partners-each influence a bat's grooming network centrality. In each of 10 simulations, virtual bats lacking social and spatial preferences moved at each scale at empirically derived rates that were either fixed or individually variable and either independent or correlated across scales. We found that numbers of partners groomed per bat were driven more by within-roost movements than by roost switching, highlighting that co-roosting networks do not fully capture bat social structure. Simulations revealed how individual variation in movement at nested spatial scales can cause false discovery and misidentification of preferred social relationships. Our model provides several insights into how nonsocial factors shape social networks.

Spatial-temporal risk factors in the occurrence of rabies in Mexico.

Rabies is a zoonotic disease that affects livestock worldwide. The distribution of rabies is highly correlated with the distribution of the vampire bat Desmodus rotundus, the main vector of the disease. In this study, climatic, topographic, livestock population, vampire distribution and urban and rural zones were used to estimate the risk for presentation of cases of rabies in Mexico by co- Kriging interpolation. The highest risk for the presentation of cases is in the endemic areas of the disease, i.e. the States of Yucatán, Chiapas, Campeche, Quintana Roo, Tabasco, Veracruz, San Luis Potosí, Nayarit and Baja California Sur. A transition zone for cases was identified across northern Mexico, involving the States of Sonora, Sinaloa, Chihuahua, and Durango. The variables topography, vampire distribution, bovine population and rural zones are the most important to explain the risk of cases in livestock. This study provides robust estimates of risk and spread of rabies based on geostatistical methods. The information presented should be useful for authorities responsible of public and animal health when they plan and establish strategies preventing the spread of rabies into rabies-free regions of México.

Bat cellular immunity varies by year and dietary habit amidst land conversion.

Monitoring the health of wildlife populations is essential in the face of increased agricultural expansion and forest fragmentation. Loss of habitat and habitat degradation can negatively affect an animal's physiological state, possibly resulting in immunosuppression and increased morbidity or mortality. We sought to determine how land conversion may differentially impact cellular immunity and infection risk in Neotropical bats species regularly infected with bloodborne pathogens, and to evaluate how effects may vary over time and by dietary habit. We studied common vampire bats (Desmodus rotundus), northern yellow-shouldered bats (Sturnira parvidens) and Mesoamerican mustached bats (Pteronotus mesoamericanus), representing the dietary habits of sanguivory, frugivory and insectivory respectively, in northern Belize. We compared estimated total white blood cell count, leukocyte differentials, neutrophil to lymphocyte ratio and infection status with two bloodborne bacterial pathogens (Bartonella spp. and hemoplasmas) of 118 bats captured in a broadleaf, secondary forest over three years (2017-2019). During this period, tree cover decreased by 14.5% while rangeland expanded by 14.3%, indicating increasing habitat loss and fragmentation. We found evidence for bat species-specific responses of cellular immunity between years, with neutrophil counts significantly decreasing in S. parvidens from 2017 to 2018, but marginally increasing in D. rotundus. However, the odds of infection with Bartonella spp. and hemoplasmas between 2017 and 2019 did not differ between bat species, contrary to our prediction that pathogen prevalence may increase with land conversion. We conclude that each bat species invested differently in cellular immunity in ways that changed over years of increasing habitat loss and fragmentation. We recommend further research on the interactions between land conversion, immunity and infection across dietary habits of Neotropical bats for informed management and conservation.

Serum proteomics reveals a tolerant immune phenotype across multiple pathogen taxa in wild vampire bats.

Bats carry many zoonotic pathogens without showing pronounced pathology, with a few exceptions. The underlying immune tolerance mechanisms in bats remain poorly understood, although information-rich omics tools hold promise for identifying a wide range of immune markers and their relationship with infection. To evaluate the generality of immune responses to infection, we assessed the differences and similarities in serum proteomes of wild vampire bats (Desmodus rotundus) across infection status with five taxonomically distinct pathogens: bacteria (Bartonella spp., hemoplasmas), protozoa (Trypanosoma cruzi), and DNA (herpesviruses) and RNA (alphacoronaviruses) viruses. From 19 bats sampled in 2019 in Belize, we evaluated the up- and downregulated immune responses of infected versus uninfected individuals for each pathogen. Using a high-quality genome annotation for vampire bats, we identified 586 serum proteins but found no evidence for differential abundance nor differences in composition between infected and uninfected bats. However, using receiver operating characteristic curves, we identified four to 48 candidate biomarkers of infection depending on the pathogen, including seven overlapping biomarkers (DSG2, PCBP1, MGAM, APOA4, DPEP1, GOT1, and IGFALS). Enrichment analysis of these proteins revealed that our viral pathogens, but not the bacteria or protozoa studied, were associated with upregulation of extracellular and cytoplasmatic secretory vesicles (indicative of viral replication) and downregulation of complement activation and coagulation cascades. Additionally, herpesvirus infection elicited a downregulation of leukocyte-mediated immunity and defense response but an upregulation of an inflammatory and humoral immune response. In contrast to our two viral infections, we found downregulation of lipid and cholesterol homeostasis and metabolism with Bartonella spp. infection, of platelet-dense and secretory granules with hemoplasma infection, and of blood coagulation pathways with T. cruzi infection. Despite the small sample size, our results suggest that vampire bats have a similar suite of immune mechanisms for viruses distinct from responses to the other pathogen taxa, and we identify potential biomarkers that can expand our understanding of pathogenesis of these infections in bats. By applying a proteomic approach to a multi-pathogen system in wild animals, our study provides a distinct framework that could be expanded across bat species to increase our understanding of how bats tolerate pathogens.

High risk of bat bites in an indigenous village in Brazil: Warning of the re-emergence of rabies among the Maxakali People

Bat-mediated human rabies is a viral zoonotic disease that poses a serious threat to the public health of traditional peoples, especially indigenous populations that maintain primitive cultural and social habits, such as the Maxakali ethnic group, located in the southeastern region of Brazil. The sociocultural habit of this population led to the emergence between April and May 2022 of the viral spillover of rabies transmitted by bats, which decimated the lives of four children from this population who maintained contact with this animal as a recreational practice. Because the vampire bats Desmodus rotundus have exceptional ecology and social characteristics that can have important effects on the dynamics of viral dispersion in this indigenous population, I present the dynamics of contact between native children and the bat and the meaning of this relationship, which involves ritualistic and recreational significance. As important as knowing the reasons for this practice is discussing some intrinsic and extrinsic factors that imply risks that intensify the vulnerability of this population to the transmission of the rabies virus at any time. In view of this, I warn of the need to adopt efficient strategies to mitigate the risks of a new emergency in this region. Although emergency containment measures were carried out during the critical period of the outbreak, such animal and environmental control actions must become routine programmatic and structuring interventions. Essential for rabies surveillance in this population is to develop culturally adapted interethnic health education campaigns to guarantee the accessibility of the Maxakali indigenous people to the content taught, so that any attempt at domestication, captivity and recreational practices with bats of any species is discouraged, thus avoiding a possible re-emergence of this anthropozoonosis that has impacted not only the epidemiological scenario in this region, but throughout Brazil, and also throughout Latin America.

Climate change linked to vampire bat expansion and rabies virus spillover

Bat‐borne pathogens are a threat to global health and in recent history have had major impacts on human morbidity and mortality. Examples include diseases such as rabies, Nipah virus encephalitis, and severe acute respiratory syndrome (SARS). Climate change may exacerbate the emergence of bat‐borne pathogens by affecting the ecology of bats in tropical ecosystems. Here, we report the impacts of climate change on the distributional ecology of the common vampire bat Desmodus rotundus across the last century. Our retrospective analysis revealed a positive relationship between changes in climate and the northern expansion of the distribution of D. rotundus in North America. Furthermore, we also found a reduction in the standard deviation of temperatures at D. rotundus capture locations during the last century, expressed as more consistent, less‐seasonal climate in recent years. These results elucidate an association between D. rotundus range expansion and a continental‐level rise in rabies virus spillover transmission from D. rotundus to cattle in the last 50 years of the 120‐year study period. This correlative study, based on field observations, offers empirical evidence supporting previous statistical and mathematical simulation‐based studies reporting a likely increase of bat‐borne diseases in response to climate change. We conclude that the D. rotundus rabies system exemplifies the consequences of climate change augmentation at the wildlife–livestock–human interface, demonstrating how global change acts upon these complex and interconnected systems to drive increased disease emergence.

Gut microbial shifts in vampire bats linked to immunity due to changed diet in human disturbed landscapes

Anthropogenic land-use change alters wildlife habitats and modifies species composition, diversity, and contacts among wildlife, livestock, and humans. Such human-modified ecosystems have been associated with emerging infectious diseases, threatening human and animal health. However, human disturbance also creates new resources that some species can exploit. Common vampire bats (Desmodus rotundus) in Latin America constitute an important example, as their adaptation to human-modified habitats and livestock blood-feeding has implications for e.g., rabies transmission. Despite the well-known links between habitat degradation and disease emergence, few studies have explored how human-induced disturbance influences wildlife behavioural ecology and health, which can alter disease dynamics. To evaluate links among habitat disturbance, diet shifts, gut microbiota, and immunity, we quantified disturbance around roosting caves of common vampire bats in Costa Rica, measured their long-term diet preferences (livestock or wildlife blood) using stable isotopes of carbon and nitrogen, evaluated innate and adaptive immune markers, and characterized their gut microbiota. We observed that bats from roosting caves with more cattle farming nearby fed more on cattle blood. Moreover, gut microbial richness and the abundance of specific gut microbes differed according to feeding preferences. Interestingly, bats feeding primarily on wildlife blood harboured a higher abundance of the bacteria Edwardsiella sp., which tended to be associated with higher immunoglobulin G levels. Our results highlight how human land-use change may indirectly affect wildlife health and emerging infectious diseases through diet-induced shifts in microbiota, with implications for host immunity and potential consequences for susceptibility to pathogens.

Phylogenetic analysis of rabies surveillance samples from north and northeast Brazil.

Viruses of the Lyssavirus genus are classified into several genotypes (GT1 to GT7), of which only GT1 (classic rabies virus-RABV) has a cosmopolitan distribution and circulates in Brazil. GT1 is subdivided into several antigenic variants (AgV) maintained in independent cycles with a narrow host range and distinct geographic distributions, namely, AgV1 and AgV2 found in dogs, AgV3 in the vampire bats Desmodus rotundus, and AgV4 and AgV6 in bats non-hematophagous Tadarida brasiliensis and Lasiurus cinereus, a common variant of marmoset (Callithrix jacchus), and crab-eating fox (Cerdocyon thous). In this study, we performed phylogenetic analysis to identify at the antigenic variant level; six RABV genomes derived from the Rabies Surveillance in the north and northeast regions of Brazil. The analysis resulted in the formation of 11 monophyletic clusters, each corresponding to a particular variant, with high bootstrap support values. The samples were positioned inside the AgV3, AgV6, and Callithrix variant clades. This is the first report of the AgV6 variant found in northern Brazil, which provides valuable information for rabies surveillance in the country. The possibility of viral spillover has been much debated, as it deals with the risk of shifting transmission from a primary to a secondary host. However, more genomic surveillance studies should be performed, with a greater number and diversity of samples to better understand the transmission dynamics of each variant to detect changes in its geographic distribution and spillover events.

A review of the diet of the common vampire bat (Desmodus rotundus) in the context of anthropogenic change.

The online version contains supplementary material available at 10.1007/s42991-023-00358-3.

Bat blunders

Bat blunders

Reducing conflict between the common vampire bat Desmodus rotundus and cattle ranching in Neotropical landscapes

AbstractIncreased cattle ranching in Neotropical landscapes has led to human–wildlife conflicts that complicate the relationship between agricultural production and biodiversity conservation. We review the literature related to conflicts between livestock production and the common vampire bat Desmodus rotundus, specifically, the factors that influence the incidence of problems caused by bites to cattle. We summarise the strategies proposed to reduce these problems and propose actions from the perspectives of cattle management, landscape ecology and the biology of the common vampire bat. The literature shows that free‐range extensive management systems, where cattle graze in areas with forest cover, near riparian zones, caves, secondary vegetation (generally shrublands and immature trees), and vegetation fragments and edges, increase the implications and the severity of the conflict. As a result of different selection forces, the wing morphology and echolocation characteristics of the common vampire bat facilitate its movement under these landscape conditions, thus favouring a scenario of greater interaction with cattle. We propose the establishment of a ‘buffer zone’ to separate the cattle as far as possible (at least 1 km) from the elements of the landscape that are key for the movement patterns of common vampire bats in cattle ranching areas. The feeding events of this species are positively associated with host availability and landscape elements that provide habitat and connectivity, which shows that the cause of this conflict originates from the process of cattle production and the invasion of the habitat of the common vampire bat. Anti‐rabies vaccination programmes in cattle and forest–cattle separation are the most important strategies to minimise conflict and prevent rabies outbreaks.

AFFINITY OF BRAZILIAN WILD MAMMAL IMMUNOGLOBULINS TO BACTERIAL PROTEINS A AND G.

Staphylococcal A and streptococcal G proteins are widely used in immunoassays when specific immunological reagents are unavailable, such as for wild animals. The affinity of bacterial proteins A and G to the immunoglobulins of seven Brazilian mammals were tested, including black-tufted marmoset (Callithrix penicillata, n = 5), golden-bellied capuchin (Sapajus xanthosternos, n = 13), woolly mouse opossum (Micoureus demerarae, n = 6), long-nosed armadillo (Dasypus novemcinctus, n = 5), collared anteater (Tamandua tetradactyla, n = 5), ocelot (Leopardus pardalis, n = 6), and vampire bat (Desmodus rotundus, n = 5). Blood samples were collected from animals that were rescued in peri-urban rainforest fragments. Sera pools of each species were tested by ELISA to determine the intensity of each bacterial protein affinity to the immunoglobulins. When comparing the affinity to both proteins, immunoglobulins from D. rotundus, S. xanthosternos, and T. tetradactyla presented a higher affinity to protein G, whereas a higher affinity to protein A was found for immunoglobulins of C. penicillata and L. pardalis. The only species that presented a very low affinity to both bacterial proteins was M. demerarae. This study can be used as a reference for further studies on the development of sensitive and specific immunodiagnostic assays to be used for the monitoring of the health of these wild mammals.

Identification of viral RNA sequences in vampire bats (Desmodus rotundus) from central Mexico

Bats are important reservoirs of viral entities that cause diverse economical and health problems in several sectors. The purpose of this study was to determine the prevalence of the rabies virus in vampire bats. We also tested for 3 other zoonotic viruses in the collected tissue. We captured 45 vampire bats (Desmodus rotundus), which were measured and sexed under standard parameters. We followed an RT-PCR reaction to amplify the viral products of four virus types: chikungunya (CHIKV), dengue (DENV), rabies (RABV) and Zika virus (ZIKV) from cerebral tissue. We obtained an amplicon of 100 bp for ZIKV in 2 samples, representing a prevalence of 4.4%. An amplicon of 581 bp for RABV was observed in 9 individuals, which is equivalent to 20% of our sample. We obtained 4 different haplotypes for RABV and a single haplotype for ZIKV. We did not record the presence of DENV and CHIKV. We corroborated the presence of the family Rhabdoviridae in the vampire bat and recorded the presence of ZIKV for the first time in this bat species.

Social effects of rabies infection in male vampire bats (Desmodus rotundus).

Rabies virus (RABV) transmitted by the common vampire bat (Desmodus rotundus) poses a threat to agricultural development and public health throughout the Neotropics. The ecology and evolution of rabies host-pathogen dynamics are influenced by two infection-induced behavioural changes. RABV-infected hosts often exhibit increased aggression which facilitates transmission, and rabies also leads to reduced activity and paralysis prior to death. Although several studies document rabies-induced behavioural changes in rodents and other dead-end hosts, surprisingly few studies have measured these changes in vampire bats, the key natural reservoir throughout Latin America. Taking advantage of an experiment designed to test an oral rabies vaccine in captive male vampire bats, we quantify for the first time, to our knowledge, how rabies affects allogrooming and aggressive behaviours in this species. Compared to non-rabid vampire bats, rabid individuals reduced their allogrooming prior to death, but we did not detect increases in aggression among bats. To put our results in context, we review what is known and what remains unclear about behavioural changes of rabid vampire bats (resumen en español, electronic supplementary material, S1).

A recombinant rabies vaccine that prevents viral shedding in rabid common vampire bats (Desmodus rotundus).

Vampire bat transmitted rabies (VBR) is a continuing burden to public health and agricultural sectors in Latin America, despite decades-long efforts to control the disease by culling bat populations. Culling has been shown to disperse bats, leading to an increased spread of rabies. Thus, non-lethal strategies to control VBR, such as vaccination, are desired. Here, we evaluated the safety and efficacy of a viral-vectored recombinant mosaic glycoprotein rabies vaccine candidate (RCN-MoG) in vampire bats (Desmodus rotundus) of unknown history of rabies exposure captured in México and transported to the United States. Vaccination with RCN-MoG was demonstrated to be safe, even in pregnant females, as no evidence of lesions or adverse effects were observed. We detected rabies neutralizing antibodies in 28% (8/29) of seronegative bats post-vaccination. Survival proportions of adult bats after rabies virus (RABV) challenge ranged from 55–100% and were not significantly different among treatments, pre- or post-vaccination serostatus, and route of vaccination, while eight pups (1–2.5 months of age) used as naïve controls all succumbed to challenge (P<0.0001). Importantly, we found that vaccination with RCN-MoG appeared to block viral shedding, even when infection proved lethal. Using real-time PCR, we did not detect RABV nucleic acid in the saliva samples of 9/10 vaccinated bats that succumbed to rabies after challenge (one was inconclusive). In contrast, RABV nucleic acid was detected in saliva samples from 71% of unvaccinated bats (10/14 sampled, plus one inconclusive) that died of the disease, including pups. Low seroconversion rates post-vaccination and high survival of non-vaccinated bats, perhaps due to earlier natural exposure, limited our conclusions regarding vaccine efficacy. However, our findings suggest a potential transmission-blocking effect of vaccination with RCN-MoG that could provide a promising strategy for controlling VBR in Latin America beyond longstanding culling programs.

Geographic Distribution of Common Vampire Bat Desmodus rotundus (Chiroptera: Phyllostomidae) Shelters: Implications for the Spread of Rabies Virus to Cattle in Southeastern Brazil.

Desmodus rotundus bats show a complex social structure and developed adaptive characteristics, considered key features of a pathogen disseminator, such as the rabies virus, among bats and other mammals, including cattle and humans. Our aim was to understand the correlation between the environment and the ecological features of these bats in bovine rabies outbreaks. Geostatistical analyses were performed, covering 104 cattle positives for rabies, between 2016 and 2018, in 25 municipalities, in addition to the characteristics of D. rotundus colonies mapped during this period in the state of São Paulo, Brazil. Data from the shelters showed that 86.15% were artificial, mainly abandoned houses (36.10%) and manholes (23.87%), in addition to demonstrating a correlation between these shelters and a higher concentration of bovine rabies cases. Due to their adaptive capacity, these bats choose shelters close to the food source, such as livestock. In Brazil, D. rotundus is the main transmitter of rabies and the cause of outbreaks in cattle and deaths in humans, considering the advance of humans in previously preserved ecosystems. There seems to be a correlation between the impact of anthropic changes on the environment, mainly for the expansion of pasture for cattle and the outbreaks of bovine rabies in this area.

How to Make a Vampire: Part II. Getting Ready to Feed

The mammalian feeding system is made up of multiple components that influence facial variation, including the masticatory muscles, bony jaw apparatus, and teeth. However, it is not fully understood how the development of these components are coordinated and are impacted by life history and diet.Bats are the only mammals that continue to nurse until they are almost adult size, and often after they become volant. Common vampire bats (Desmodus rotundus) have a relatively prolonged juvenile period among bats, can nurse up to nine months, and later solely subsist off of blood. Feeding system maturity may therefore be delayed in bats, and particularly delayed in Desmodus, as a result of their lengthy juvenile period and liquid diet. In this study, we examine the developmental maturity of the cranium and feeding apparatus in the late fetus of a common vampire bat (Desmodus rotundus) relative to an adult (its mother).The heads of each specimen were microCT scanned twice. Conventional microCT was used to image mineralized tissues. Diffusible iodine‐based contrast‐enhanced CT (diceCT) imaging was used to image soft tissues. Cranial length and palate length measurements were acquired from unstained scans to evaluate size and jaw apparatus development. Masticatory muscles (e.g., medial pterygoid, zygomaticomandibularis) and permanent tooth crypt volumes were acquired from stained tissue scans to evaluate masticatory muscle and tooth development. Developmental maturity of these structures was assessed by calculating a percentage of the growth completed (i.e., [fetal muscle volume/adult muscle volume]*100).In the fetus, permanent tooth crypt volume is already comparable to the adult condition despite cranial length and palate length being &lt;75% of adult size. Masticatory muscle volume maturity is highest in the lateral pterygoid muscle (~35%), whereas other masticatory muscles are far less developed (e.g., medial pterygoid volume maturity, ~20%; temporalis profundus volume maturity, ~20%; temporalis medius volume maturity, ~6%).These results reveal highly precocious permanent tooth development in Desmodus. Although this may facilitate transition to hematophagy, Desmodus do not fly until eight to ten weeks, so the precocious incisors may primarily aid the infant to grip its mother’s skin. Differential development of the masticatory muscles may also be influenced by the need for young bats to use their mouths to help anchor themselves to their mother early in life. This may explain the advanced maturity of the lateral pterygoid muscle, which would protrude the jaw and help to facilitate a more secure grip.

A two-step metagenomics approach for the identification and mitochondrial DNA contig assembly of vertebrate prey from the blood meals of common vampire bats (Desmodus rotundus)

The feeding behaviour of the sanguivorous common vampire bat (Desmodus rotundus) facilitates the transmission of pathogens that can impact both human and animal health. To formulate effective strategies in controlling the spread of diseases, there is a need to obtain information on which animals they feed on. One DNA-based approach, shotgun sequencing, can be used to obtain such information. Even though it is costly, shotgun sequencing can be used to simultaneously retrieve prey and vampire bat mitochondrial DNA for population studies within one round of sequencing. However, due to the challenges of analysing shotgun sequenced metagenomic data such as false negatives/positives and typically low proportion of reads mapped to diet items, shotgun sequencing has not been used for the identification of prey from common vampire bat blood meals. To overcome these challenges and generate longer mitochondrial contigs which could be useful for prey population studies, we shotgun sequenced common vampire bat blood meal samples (n = 8) and utilised a two-step metagenomic approach based on combining existing bioinformatic workflows (alignment and mtDNA contig assembly) to identify prey. After validating our results from detections made through metabarcoding, we accurately identified the common vampire bats’ prey in six out of eight samples without any false positives. We also generated prey mitochondrial contig lengths between 138 bp to 3231 bp (median = 770 bp, Q1 = 262 bp, Q3 = 1766 bp). This opens the potential to conduct phylogenetic and phylogeographic monitoring of elusive prey species in future studies, through the analyses of blood meal metagenomic data.

Forced proximity promotes the formation of enduring cooperative relationships in vampire bats.

Spatial assortment can be both a cause and a consequence of cooperation. Proximity promotes cooperation when individuals preferentially help nearby partners, and conversely, cooperation drives proximity when individuals move towards more cooperative partners. However, these two causal directions are difficult to distinguish with observational data. Here, we experimentally test if forcing randomly selected pairs of equally familiar female common vampire bats (Desmodus rotundus) into close spatial proximity promotes the formation of enduring cooperative relationships. Over 114 days, we sampled 682 h of interactions among 21 females captured from three distant sites to track daily allogrooming rates over time. We compared these rates before, during and after a one-week period, during which we caged random triads of previously unfamiliar and unrelated vampire bats in proximity. After the week of proximity when all bats could again freely associate, the allogrooming rates of pairs forced into proximity increased more than those of the 126 control pairs. This work is the first to experimentally demonstrate the causal effect of repeated interactions on cooperative investments in vampire bats. Future work should determine the relative importance of mere association versus interactions (e.g. reciprocal allogrooming) in shaping social preferences.