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Bats perform various ecological and socio-economic functions but are also associated with the transmission of zoonotic diseases. This study investigated how awareness of bats as vectors of diseases has influenced their conservation in Ghana. Data were drawn from focus group discussions, key informant interviews, and questionnaire administration from five selected Ghanaian communities. The results showed that the level of awareness of bats as vectors of zoonotic diseases was high among the respondents but this did not change people's attitudes toward bats and what they used the bats for. Another important finding was that unsustainable harvests of bats for food and other uses was just as much a conservation threat as associating bats with zoonoses. Because of how vulnerable bats are, findings from this study suggest that the Ghana Forestry Commission should strengthen legislation against the hunting of bats, commercialization of bat bushmeat, and destruction of bats' habitats. [ABSTRACT FROM AUTHOR]

Animals deliver an important ecosystem service by dispersing plant seeds. Seed dispersers have different effects on the germination success of seeds. This study aimed at examining the effect of seed processing by the patas monkey (Erythrocebus patas) and two flying foxes (Micropteropus pusillus and Epomophorus gambianus) on the germination success of African ebony (Diospyros mespiliformis). Flying foxes and patas monkeys were kept in cages and fed ad libitum with African ebony fruits. Seeds processed were collected, measured, and germinated. Seeds processed by monkeys and flying foxes were compared to control seeds which were removed by hand from fruits. Our results showed that the patas monkey and flying foxes preferably processed smaller seeds. Flying foxes improved the germination success from 6.67 to 72.5%. They also reduced the mean germination time up to 5 days. The patas monkey also improved the germination success from 6.67 to 52.5% and reduced the mean germination time up to 4 days. The effect of flying foxes and the patas monkey on the seed germination and its implication for the African ebony plantation dynamic should be explained to communities for their conservation.

Fruit bats serve as crucial bioindicators, seed dispersers, pollinators, and contributors to food security within ecosystems. However, their population and distribution were threatened by climate change and anthropogenic pressures. Understanding the impacts of these pressures through mapping distribution and habitat suitability is crucial for identifying high‐priority areas and implementing effective conservation and management plans. We predicted the distribution and extent of habitat suitability for Rousettus aegyptiacus and Epomophorus labiatus under climate change scenarios using average predictions from four different algorithms to produce an ensemble model. Seasonal precipitation, population index, land‐use land cover, vegetation, and the mean temperature of the driest quarter majorly contributed to the predicted habitat suitability for both species. The current predicted sizes of suitable habitats for R. aegyptiacus and E. labiatus were varied, on average 60,271.4 and 85,176.1 km2, respectively. The change in species range size for R. aegyptiacus showed gains in suitable areas of 24.4% and 22.8% in 2050 and 2070, respectively. However, for E. labiatus, suitable areas decreased by 0.95% and 2% in 2050 and 2070, respectively. The range size change of suitable areas between 2050 and 2070 for R. aegyptiacus and E. labiatus shows losses of 1.5% and 1.2%, respectively. The predicted maps indicate that the midlands and highlands of southern and eastern Ethiopia harbor highly suitable areas for both species. In contrast, the areas in the northern and central highlands are fragmented. The current model findings show that climate change and anthropogenic pressures have notable impacts on the geographic ranges of two species. Moreover, the predicted suitable habitats for both species are found both within and outside of their historical ranges, which has important implications for conservation efforts. Our ensemble predictions are vital for identifying high‐priority areas for fruit bat species conservation efforts and management to mitigate climate change and anthropogenic pressures. [ABSTRACT FROM AUTHOR]

Traditional method of artificial light was evaluated against fruit bat, Pteropus giganteus in ber (Ziziphus jujube) orchards of Punjab Agricultural University, Ludhiana during 2017-18 and 2018-19, since; no study has been done in Punjab to assess ber fruit damage and management of fruit bats. Ber is a tropical and deciduous fruit crop which is damaged by different pests among which fruit bats are important ones. Our results reported P. giganteus damage to ber fruits which was economical and ranged from 9.72-11.6% and per tree from 9.96-13.40 kg having yield of 103.3-117.0 kg. Damage of fruit bats was minimized by using traditional and eco-friendly method of artificial light using LED bulbs having different watts, which requires only one time initial cost. It is concluded that on installation of 16 LED bulbs/acre of 30 watt power at a distance of 50 feet from each other in downward position at height of 6 feet above top of tree canopy in orchard having 72 trees planted at recommended distance of 25×25 feet, we can reduce fruit bat damage to minimum level. This non-lethal and non-polluting method can give huge net economic return of Rs. 10646.0/acre to ber fruit growers which will increase their farm income and also helps in bat conservation. [ABSTRACT FROM AUTHOR]

Pteropodidae is the only phytophagous bat family that predominantly depends on visual and olfactory cues for orientation and foraging. During daytime, pteropodids of different species roost in sites with varying light exposure. Pteropodids have larger eyes relative to body size than insectivorous bats. Retinal topography has been studied in less than 10% of the approximately 200 pteropodid species, a behavioural estimation of spatial resolution is available only for Pteropus giganteus, and little is known about the relationship between their roost site preference and visual ecology. We present retinal ganglion cell topographic maps and anatomical estimates of spatial resolution in three southern Indian pteropodid species with different roosting preferences. Ganglion cell densities are between 1,000 and 2,000 cells/mm2 in the central retina and lower in the dorsal and ventral periphery. All three species have a temporal area in the retina with peak ganglion cell densities of 4,600–6,600 cells/mm2. As a result, the foliage-roosting Cynopterus sphinx and the cave-roosting Rousettus leschenaultii have similar anatomical resolution (2.7 and 2.8 cycles/degree, respectively). The anatomical estimate for the larger tree-roosting P. giganteus (4.0 cycles/degree) is higher than the spatial resolution determined earlier in behavioural tests. Like other pteropodids and unlike other vertebrates, all three species have choroidal papillae. Based on 15 pteropodid species studied to date, we find no relationship between roost type and eye size or visual acuity. For a general understanding of the sensory ecology of pteropodids that perform key ecosystem services in the tropics, it will be essential to study additional species. [ABSTRACT FROM AUTHOR]

Pteropine orthoreovirus (PRV), an emerging bat‐borne virus, has been linked to cases of acute respiratory infections (ARI) in humans. The prevalence, epidemiology and genomic diversity of PRV among ARI of unknown origin were studied. Among 632 urban outpatients tested negative for all known respiratory viruses, 2.2% were PRV‐positive. Patients mainly presented with moderate to severe forms of cough, sore throat and muscle ache, but rarely with fever. Phylogenetic analysis revealed that over 90% of patients infected with the Melaka virus (MelV)‐like PRV, while one patient infected with the Pulau virus previously found only in fruit bats. Human oral keratinocytes and nasopharyngeal epithelial cells were susceptible to clinical isolates of PRV, including the newly isolated MelV‐like 12MYKLU1034. Whole genome sequence of 12MYKLU1034 using Nanopore technique revealed a novel reassortant strain. Evolutionary analysis of the global PRV strains suggests the continuous evolution of PRV through genetic reassortment among PRV strains circulating in human, bats and non‐human primate hosts, creating a spectrum of reassortant lineages with complex evolutionary characteristics. In summary, the role of PRV as a common etiologic agent of ARI is evident. Continuous monitoring of PRV prevalence, pathogenicity and diversity among human and animal hosts is important to trace the emergence of novel reassortants. [ABSTRACT FROM AUTHOR]

Abstract Background Fruit bats play an important role in pollination and seed dispersal, and their conservation is important to maintain the productivity of some crops and natural ecosystems. The objective of this study was to investigate the knowledge, attitudes, and perception of fruit bats by orchard farmers and agricultural communities in Pakistan. Methods The present survey was conducted in two districts (i.e. Sheikhupura and Malakand districts) within Punjab and Khyber Pakhtunkhwa provinces based on the higher number of fruit growing areas and bat roosting sites. A total of 200 (100 per district) close-ended questionnaires with 53 questions were administered to randomly selected respondents within the selected communities associated with fruit orchards, including orchard owners, laborers, and members of the surrounding community. Each questionnaire was divided into seven sections (i.e., demographic information, environmental and public health effects of bats, knowledge about bats, perception and control of bats, non-lethal methods adopted to control bats, and different myths about bats). Results A majority of respondents (59%, n = 118) mis-classified bats as birds instead of mammals despite more than 84% reporting that they have observed bats. Nearly 71.5% of orchard farmers perceived that their fruits are contaminated by bats during consumption, and a majority believe that bats destroy orchards (62.5%) and are responsible for spreading disease. Mythology about bats was ambiguous, as 49% of those surveyed did not perceived bats to bring good luck (49%), and 50% did not perceived them to be bad omens either. Most respondents have never killed a bat (68%) nor would they kill a bat if given the opportunity (95%). Regarding the control of bats, the greatest percentage of respondents strongly disagree with shooting bats (36%) and strongly agree with leaving bats alone (42.5%). Conclusions This study provides a better understanding of the sociodemographic factors associated with knowledge, attitude and perception of bats from fruit orchard owners, labourers and local people. We recommend educational interventions for targeted groups in the community, highlighting the ecosystem services and importance of bat conservation to improve people’s current knowledge regarding the role of bats and reduce direct persecution against bats.

Abstract Background Animals are important vectors for the dispersal of a wide variety of plant species, and thus play a key role in maintaining the health and biodiversity of natural ecosystems. On oceanic islands, flying-foxes are often the only seed dispersers or pollinators. However, many flying-fox populations are currently in decline, particularly those of insular species, and this has consequences for the ecological services they provide. Knowledge of the drivers and the scale of flying-fox movements is important in determining the ecological roles that flying-foxes play on islands. This information is also useful for understanding the potential long-term consequences for forest dynamics resulting from population declines or extinction, and so can aid in the development of evidence-based ecological management strategies. To these ends, we examined the foraging movements, floral resource use, and social interactions of the Critically Endangered Christmas Island flying-fox (Pteropus natalis). Methods Utilization distributions, using movement-based kernel estimates (MBKE) were generated to determine nightly foraging movements of GPS-tracked P. natalis (n = 24). Generalized linear models (GLMs), linear mixed-effect models (LMMs), and Generalized linear mixed-effects model (GLMMs) were constructed to explain how intrinsic factors (body mass, skeletal size, and sex) affected the extent of foraging movements. In addition, we identified pollen collected from facial and body swabs of P. natalis (n = 216) to determine foraging resource use. Direct observations (n = 272) of foraging P. natalis enabled us to assess the various behaviors used to defend foraging resources. Results Larger P. natalis individuals spent more time foraging and less time traveling between foraging patches, traveled shorter nightly distances, and had smaller overall foraging ranges than smaller conspecifics. Additionally, larger individuals visited a lower diversity of floral resources. Conclusions Our findings suggest that smaller P. natalis individuals are the primary vectors of long-distance dispersal of pollen and digested seeds in this species, providing a vital mechanism for maintaining the flow of plant genetic diversity across Christmas Island. Overall, our study highlights the need for more holistic research approaches that incorporate population demographics when assessing a species’ ecological services.

Nelson Bay orthoreovirus (NBV) is an emerging bat-borne virus and causes respiratory tract infections in humans sporadically. Over the last two decades, several strains genetically related to NBV were isolated from humans and various bat species, predominantly in Southeast Asia (SEA), suggesting a high prevalence of the NBV species in this region. In this study, an orthoreovirus (ORV) belonging to the NBV species was isolated from Indonesian fruit bats' feces, tentatively named Paguyaman orthoreovirus (PgORV). Serological studies revealed that 81.2% (108/133) of Indonesian fruit bats sera had neutralizing antibodies against PgORV. Whole-genome sequencing and phylogenetic analysis of PgORV suggested the occurrence of past reassortments with other NBV strains isolated in SEA, indicating the dispersal and circulation of NBV species among bats in this region. Intranasal PgORV inoculation of laboratory mice caused severe pneumonia. Our study characterized PgORV's unique genetic background and highlighted the potential risk of PgORV-related diseases in Indonesia. • A high seroprevalence of NBV was observed in multiple species of fruit bats in different areas of Indonesia. • PgORV, a novel strain of NBV, was isolated from Indonesian fruit bats. • PgORV was pathogenic and caused respiratory disease in mice. • Phylogenetic analysis of PgORV provides evidence for genetic reassortment between NBVs in fruit bats. [ABSTRACT FROM AUTHOR]

Fruit bats serve as an important reservoir for many zoonotic pathogens, including Nipah virus, Hendra virus, Marburg virus and Lyssavirus. To gain a deeper insight into the virological characteristics, pathogenicity and zoonotic potential of bat-borne viruses, recovery of infectious viruses from field samples is important. Here, we report the isolation and characterization of a mammalian orthoreovirus (MRV) from a large flying fox ( Pteropus vampyrus ) in Indonesia, which is the first detection of MRV in Southeast Asia. MRV was recovered from faecal samples of three different P. vampyrus in Central Java. Nucleotide sequence analysis revealed that the genome of the three MRV isolates shared more than 99% nucleotide sequence identity. We tentatively named one isolated strain as MRV12-52 for further analysis and characterization. Among 10 genome segments, MRV12-52 S1 and S4, which encode the cell-attachment protein and outer capsid protein, had 93.6 and 95.1% nucleotide sequence identities with known MRV strains, respectively. Meanwhile, the remaining genome segments of MRV12-52 were divergent with 72.9-80.7 % nucleotide sequence identities. Based on the nucleotide sequence of the S1 segment, MRV12-52 was grouped into serotype 2, and phylogenetic analysis demonstrated evidence of past reassortment events. In vitro characterization of MRV12-52 showed that the virus efficiently replicated in BHK-21, HEK293T and A549 cells. In addition, experimental infection of laboratory mice with MRV12-52 caused severe pneumonia with 75% mortality. This study highlights the presence of pathogenic MRV in Indonesia, which could serve as a potential animal and public health concern.

Urbanization is driving many species to inhabit modified landscapes, but our understanding of how species respond to this remains limited. Bats are particularly vulnerable due to their life‐history traits but have received little attention. We describe the roosting behavior and roost site selection, including maternity roosts, for the Gambian epauletted fruit bat (Epomophorus gambianus) within a modified forest‐savannah transition ecological zone in Ghana, West Africa. We compared characteristics of roost and non‐roost sites to test the hypotheses that roost site selection is non‐random and that maternity roost site selection differs from non‐maternity roosts. Male bats were more likely to switch roost (mean = 0.49 ± 0.23 bat days, N = 23) than females (mean = 0.33 ± 0.18 bat days, N = 7) while linear distances between roosts used by males (255 ± 254 m) were significantly longer than for females (102 ± 71 m) (t = 4.50, df = 86, p <.0001). Roost trees were more likely than non‐roost trees to be bigger, taller, occur closer to buildings, and be in relatively open and less mature plots; maintaining such trees in modified landscapes could benefit the species. Lactating bats selected a subset of roost trees but significantly, those that contained a greater number of bats, a strategy which may reflect predator avoidance, or other social co‐operation benefits. Although there was a preference for five tree species, other trees with preferred characteristics were also used. Our findings contribute to the understanding of how species utilize modified landscapes, which is important in the management of biodiversity in the Anthropocene. [ABSTRACT FROM AUTHOR]

Litchi (Litchi chinensis) is an important sub-tropical evergreen fruit crop of Punjab which is damaged by fruit bats (Pteropus giganteus). Since no study has been done in Punjab to assess fruit damage and control of fruit bats in litchi, the present study was conducted in litchi orchards at two different locations (six sites), Gurdaspur (Regional Research Station (PAU), villages Ranjit Bagh and Tibar) and Pathankot (villages Sujanpur, Balusa and Malikpur) each having three replications, during 2018 and 2019. Our results reported that yield loss (%) to litchi fruits by P. giganteus ranged from 6.85 to 8.93% and damage 5.59 kg/tree, having an average yield of 74.09 kg/tree. The average economic litchi fruit loss was calculated to be Rs. 32,232.0/acre. This damage to the litchi fruit crop was minimized by a non-lethal and non-polluting method (LED bulbs) with a one-time installation cost. It is concluded that after installation of 16 LED bulbs of 30 watts per acre at a distance of 50 feet from each other in an upward position at the height of 8 feet above tree canopy in orchard having 72 trees planted at a distance of 25x25 feet, we can reduce fruit bat damage to lower level and can give net economic return ofRs. 13448.0/acre to litchi fruit growers which will increase their farm income and help in conservation of fruit bats. [ABSTRACT FROM AUTHOR]

Background: Animals are important vectors for the dispersal of a wide variety of plant species, and thus play a key role in maintaining the health and biodiversity of natural ecosystems. On oceanic islands, flying-foxes are often the only seed dispersers or pollinators. However, many flying-fox populations are currently in decline, particularly those of insular species, and this has consequences for the ecological services they provide. Knowledge of the drivers and the scale of flying-fox movements is important in determining the ecological roles that flying-foxes play on islands. This information is also useful for understanding the potential long-term consequences for forest dynamics resulting from population declines or extinction, and so can aid in the development of evidence-based ecological management strategies. To these ends, we examined the foraging movements, floral resource use, and social interactions of the Critically Endangered Christmas Island flying-fox (Pteropus natalis). Methods: Utilization distributions, using movement-based kernel estimates (MBKE) were generated to determine nightly foraging movements of GPS-tracked P. natalis (n = 24). Generalized linear models (GLMs), linear mixed-effect models (LMMs), and Generalized linear mixed-effects model (GLMMs) were constructed to explain how intrinsic factors (body mass, skeletal size, and sex) affected the extent of foraging movements. In addition, we identified pollen collected from facial and body swabs of P. natalis (n = 216) to determine foraging resource use. Direct observations (n = 272) of foraging P. natalis enabled us to assess the various behaviors used to defend foraging resources. Results: Larger P. natalis individuals spent more time foraging and less time traveling between foraging patches, traveled shorter nightly distances, and had smaller overall foraging ranges than smaller conspecifics. Additionally, larger individuals visited a lower diversity of floral resources. Conclusions: Our findings suggest that smaller P. natalis individuals are the primary vectors of long-distance dispersal of pollen and digested seeds in this species, providing a vital mechanism for maintaining the flow of plant genetic diversity across Christmas Island. Overall, our study highlights the need for more holistic research approaches that incorporate population demographics when assessing a species' ecological services. [ABSTRACT FROM AUTHOR]

Introduction: Nipah virus (NiV) was reported for the first time from the Kampung Sungai Nipah village of Malaysia in 1998. Since then, there have been multiple outbreaks, all of them in South- and South-East Asia. According to the World Health Organization (WHO), up to 75% of Nipah infections were proven to be fatal. Nipah virus belongs to the group of Biosafety Level-4 pathogen associated with high case fatality rate (40-75%). Methodology: According to the PRISMA guidelines for 2020, we searched in four medical databases (PubMed, Google Scholar, EMBASE and Scopus) and selected relevant studies from the past twenty years till November 2021. Review: Nipah virus was first detected in Malaysia's Kampung Sungai Nipah in 1998. By May 1999, the Malaysia Ministry of Health in association with the Centers for Disease Control (CDC) reported a total of 258 cases with a case fatality rate of almost 40%. Nipah in Kozhikode: Experts from the Pune Institute and Bhopal's National Institute of High Security Animal Diseases had collected Bat samples from Pazhoor in Chathamangalam gram panchayat (where a 12-year-old died due to Nipah infection on September 5 carried antibodies of the virus). All Indian outbreaks have seen person-to-person transmission. The virus found in Kerala differed from those two variants in terms of genetic structure. It also differed by 1.96% from the Bangladesh variant. The difference with the Malaysian variant was 8.42%. While PCR is the most sensitive technique for diagnosing active NiV infection, NiV-specific IgM ELISA offers a serological option when PCR is not available. Conclusion: Understanding the fruit bat ecology, NiV illness seasonality, and the transmission risk of various intermediate species requires a One Health approach. The danger of reintroduction into animal or human populations cannot be handled without a thorough understanding of the wildlife reservoir. [ABSTRACT FROM AUTHOR]

We detected Marburg virus RNA in rectal swab samples from Egyptian rousette bats in South Africa in 2017. This finding signifies that fecal contamination of natural bat habitats is a potential source of infection for humans. Identified genetic sequences are closely related to Ravn virus, implying wider distribution of Marburg virus in Africa.

Salmonella enterica and Campylobacter jejuni are significant foodborne zoonotic pathogens causing gastroenteritis in humans. Domestic animals are commonly implicated as reservoirs of S. enterica and C. jejuni, but both are also detected in wild animals. Salmonella enterica serovar Typhimurium is the most common cause of human salmonellosis in Australia; however, Salmonella enterica serovar Wangata is associated with sporadic human outbreaks in New South Wales and wild animals may be a potential reservoir. To determine if wild grey‐headed flying foxes (GHFF; Pteropus poliocephalus) are reservoirs of Salmonella and Campylobacter, faecal samples were collected from three GHFF colonies in New South Wales and cultured for the presence of Salmonella and Campylobacter. One Salmonella isolate was cultured from 254 GHFF faecal samples (0.39%). Whole genome sequencing was used to genetically characterise the Salmonella isolate and perform phylogenetic analysis. The GHFF isolate was determined to be Salmonella Typhimurium ST19. The GHFF isolate carried a virulence plasmid and other virulence factors, but did not exhibit antimicrobial resistance. Phylogenetic analysis determined that the GHFF isolate was most closely related to a cluster of six isolates: four from human salmonellosis cases in Queensland and two from Australian livestock. Neither Campylobacter nor Salmonella Wangata were cultured from the 254 GHFF faecal samples. This study concluded that wild GHFF in New South Wales are not major reservoirs for Salmonella, and the zoonotic risks associated with S. enterica carriage by urban GHFF are low for the general public. [ABSTRACT FROM AUTHOR]

We conducted an in-depth characterization of the Nipah virus (NiV) isolate previously obtained from a Pteropus lylei bat in Cambodia in 2003 (CSUR381). We performed full-genome sequencing and phylogenetic analyses and confirmed CSUR381 is part of the NiV-Malaysia genotype. In vitro studies revealed similar cell permissiveness and replication of CSUR381 (compared with 2 other NiV isolates) in both bat and human cell lines. Sequence alignments indicated conservation of the ephrin-B2 and ephrin-B3 receptor binding sites, the glycosylation site on the G attachment protein, as well as the editing site in phosphoprotein, suggesting production of nonstructural proteins V and W, known to counteract the host innate immunity. In the hamster animal model, CSUR381 induced lethal infections. Altogether, these data suggest that the Cambodia bat-derived NiV isolate has high pathogenic potential and, thus, provide insight for further studies and better risk assessment for future NiV outbreaks in Southeast Asia.

An asynchronous fruit-ripening strategy can enhance the chance of seed dispersal by providing ripe fruits for an extended period to foragers. However, mechanisms associated with this strategy that can facilitate seed dispersal are understudied. This study aimed to investigate whether the chemical components (minerals and secondary metabolites) of a bat fruit with ripening asynchrony change along its ontogeny (Rubiaceae: Neolamarckia cadamba). We predicted that the seed-to-pulp ratio would increase along with fruit ripeness. The chemical components of the fruit were also predicted to change along their ontogenesis in favour of fruit selection and seed dispersal by fruit bats. Our study shows that the asynchronous fruiting strategy limited the number of ripe fruits daily so that fruits were available at a steady rate. As predicted, the seed-to-pulp ratio of each fruit increased along with fruit development. A fruit's mineral concentration also increased as fruit developed, with a sharp jump at full ripeness, when fruit colour also changed. In contrast, the concentration of secondary metabolite compositions decreased gradually during the process of ontogeny. Fruit bats (Pteropodidae: Pteropus giganteus and Cynopterus sphinx) were the only nocturnal frugivore visitors of these trees and their fruit selection was driven by fruit size and colour. Both bats preferably consumed ripe fruits, which had a higher concentration of attractants (essential minerals) and a lower concentration of deterrents (secondary metabolites), supplemented with a higher seed-to-pulp ratio. The bats exhibited different foraging patterns and home ranges resulting in dispersal (as measured by feeding roost location) occurring across different spatial scales. Our study shows that the chemical components involved in an asynchronous fruit-ripening process could select for extended fruit availability by intensifying the demand for each ripe fruit among legitimate seed dispersers, which increases the likelihood of fruits being dispersed away from parent crowns. [ABSTRACT FROM AUTHOR]

Pteropus bats are the natural reservoir for Nipah virus, and in Bangladesh, it is transmitted to people through consumption of raw or fermented date palm sap. Our objective was to understand seasonal patterns of bat feeding on date palm sap at a location where sap is collected year-round. Seven nights each month over three years, we mounted infrared cameras in four trees to observe bats' feeding behavior at date palm trees harvested for fermented sap production. We described the frequency of bat visits, duration of bat visits, and duration of bat-sap contact by month and by year. We captured 42,873 bat visits during 256 camera-nights of observation, of which 3% were Pteropus and 94% were non-Pteropus bats. Though the frequency of Pteropus bat visits to each tree/night was much lower than non-Pteropus bat visits, Pteropus bats stayed in contact with sap longer than non-Pteropus bats. Frequency of bat visits was higher during winter compared to other seasons, which may arise as a consequence of limited availability of food sources during this period or may be related to seasonal characteristics of the sap. Seasonal alignment of sap consumption by humans and bats may have consequences for viral spillover into humans. [ABSTRACT FROM AUTHOR]

The threatened Mauritian Flying Fox (Pteropus niger) has been facing repeated mass-culling since 2015 due to the perceived damage to commercial fruits. The significant reduction in numbers from that period had led to its International Union for Conservation of Nature (IUCN) Red List Status being up-listed to endangered status. The purpose of the study is to employ a contingency valuation method (CVM) to determine the factors influencing the decision to contribute and how much to contribute for conserving the Mauritian Flying Fox by the Mauritian public in the midst of the human-wildlife conflict (HWC). A household drop-off survey with a sample size of 525 observations was employed. Favourable environmental attitudes, higher perceived ability to contribute (PAC), better knowledge about bats, higher aesthetic value of bats and lower negativistic attitudes towards bats were found to increase the probability of contributing to the conservation of the species. Conditional on these results, individuals with higher knowledge about bats and perceived ability to contribute were found willing to pay more for conserving the species. The findings help us to draw attention on the perspective of supporting a preservation fund for the Mauritian Flying Fox.

Population genetics has been widely employed in conservation studies to assess genetic diversity, gene flow, and population structure. This information can be used to understand the population's fitness. The Philippine dawn bat Eonycteris robusta is a nectarivorous fruit bat that is ecologically important because of its capability to pollinate trees. It is categorized as "Vulnerable" in the Philippine Red List and the IUCN (International Union on the Conservation of Nature) Red List. Fragmentation and loss of forest habitats along with biogeographical factors might impact gene flow and affect the genetic diversity of this species. Thus, a population genetic study was done to assess gene flow and population structure of this species from two sites in the island of Luzon: Palanan, Isabela and Puning Cave, Doña Remedios Trinidad, Bulacan. Ten (10) microsatellite markers were developed from the whole genome of E. robusta and these were used for genotyping individuals. Observed heterozygosity (Ho) was generally lower than the expected (He), suggesting loss of heterozygosity. The inbreeding coefficient values (F) across all loci were greater than 0.5, which meant that mating between closely related individuals was frequent. A low level of gene flow was detected between Palanan and Puning Cave with the presence of structuring (Fst = 0.190 ± 0.003; Nm = 1.068 ± 0.020). Deviations from the Hardy-Weinberg equilibrium (HWE) were also observed for most of the loci tested. Clustering was also evident in the principal coordinates analysis (PCoA) plots, showing a distinct cluster of Puning Cave samples separate from Palanan, Isabela. This study has shown that within island clustering is possible, which may be driven by ecological factors such as discontinuity of available habitats for E. robusta or by biogeographical features like distance and topography. [ABSTRACT FROM AUTHOR]

The "Species from Feces" DNA barcoding offers new opportunities to study the challenging taxonomy and systematics of Philippine bats using a minimally-invasive strategy that employs a short 200-bp mitochondrial encoded cytochrome c oxidase I (mt COI) sequence. A pilot application of the technique to five species of fruit bats collected from Davao City, Philippines revealed accurate species identification and the extended ability to assess genetic diversity and evolutionary relationships. The 95-100% sequence identity matched with the field identification of bats, including the endemic Ptenochirus jagori, although only 62% of the samples could be sequenced. A decreasing trend in genetic diversity was noted from widespread bat species such as Rousettus amplexicaudatus, Cynopterus brachyotis, and Macroglossus minimus to species with limited geographic distribution (e.g. P. jagori) or possible recent colonization (e.g. Eonycteris spelaea). Genetic diversity, principal coordinate analysis (PCoA), and phylogenetic analysis also showed distinct genetic lineages of C. brachyotis, R. amplexicaudatus, and M. minimus from their conspecifics outside the Philippines, while E. spelaea and the endemic P. jagori exhibited genetic homogeneity. The findings on genetic diversity and relationships were consistent with previous studies using longer COI segment or other biomarkers. In conclusion, the Species from Feces DNA barcoding presents a minimally invasive and pragmatic approach to explore bat assemblages with the additional utility to examine genetic structures and relationships, which may be used to support studies on diversity, evolution, and biogeography, thereby rapidly facilitate conservation initiatives. [ABSTRACT FROM AUTHOR]

Fur properties play a critical role in the thermoregulation of mammals and are becoming of particular interest as the frequency, intensity, and duration of extreme heat events are increasing under climate change. Australian flying-foxes are known to experience mass die-offs during extreme heat events, yet little is known about how different fur properties affect their thermoregulatory needs. In this study, we examined the differences and patterns in fur properties among and within the four mainland Australian flying-fox species: Pteropus poliocephalus , P. alecto , P. conspicillatus , and P. scapulatus. Using museum specimens, we collected data on fur solar reflectance, fur length and fur depth from the four species across their distribution. We found that P. poliocephalus had significantly longer and deeper fur, and P. alecto had significantly lower fur solar reflectivity, compared with the other species. Across all species, juveniles had deeper fur than adults, and females of P. alecto and P. conspicillatus had deeper fur than males. The biophysical effects of these fur properties are complex and contingent on the degree of exposure to solar radiation, but they may help to explain the relatively higher mortality of P. alecto and of juveniles and females that is commonly observed during extreme heat events. The variation in fur properties of flying-foxes can help us understand why there are differences in survival rates among different species, sexes, and ages during extreme heat events. We found that there were distinct differences in the length, depth, and solar reflectance of fur among different species and demographics, which can cause differences in the experienced heat load. Thus, understanding exactly how interactions between fur properties affect heat transfer can help us explain the higher mortality of some species and demographics. Photo by Himali Ratnayake. [ABSTRACT FROM AUTHOR]

We detected Marburg virus RNA in rectal swab samples from Egyptian rousette bats in South Africa in 2017. This finding signifies that fecal contamination of natural bat habitats is a potential source of infection for humans. Identified genetic sequences are closely related to Ravn virus, implying wider distribution of Marburg virus in Africa. [ABSTRACT FROM AUTHOR]

We detected a high seroprevalence of Marburg virus (MARV) antibodies in fruit bats in South Africa; 19.1% of recaptured bats seroconverted. The MARV RNA isolated closely resembled the 1975 Ozolin strain. These findings indicate endemic MARV circulation in bats in South Africa and should inform policies on MARV disease risk reduction.

Roosts provide bats with place for daytime sheltering, protection from weather and predators, mating, and social interaction. Movements between multiple roosts are often necessary, either due to limited roost life, changes in roost conditions or demands at different times of the year. Information transfer is an important contributor to day‐roosting behaviour and typically exhibits non‐random social assortment dynamics. Some individuals appear to explore and share roost discoveries more often than others, though it remains unclear whether associations are stronger between close relatives than less related individuals. In the present study, network analysis, in combination with genetic and spatial data, was used to explore the roosting behaviour of Egyptian fruit bats (Rousettus aegyptiacus) within an isolated deme. Our results showed that the roosts had distinct core–periphery structure. The core of the winter roost network was represented by only two roosts, while in spring, the season of food scarcity, the core was represented by multiple roosts, suggesting their potential role as centres, where information about roosts and foraging sites is exchanged. We found no relationship between relatedness and roost sharing over two seasons. These results provide strong support that Egyptian fruit bats do not roost preferentially with relatives, in contrast to many animal populations where individuals preferentially associate with kin. [ABSTRACT FROM AUTHOR]

We conducted an in-depth characterization of the Nipah virus (NiV) isolate previously obtained from a Pteropus lylei bat in Cambodia in 2003 (CSUR381). We performed full-genome sequencing and phylogenetic analyses and confirmed CSUR381 is part of the NiV-Malaysia genotype. In vitro studies revealed similar cell permissiveness and replication of CSUR381 (compared with 2 other NiV isolates) in both bat and human cell lines. Sequence alignments indicated conservation of the ephrin-B2 and ephrin-B3 receptor binding sites, the glycosylation site on the G attachment protein, as well as the editing site in phosphoprotein, suggesting production of nonstructural proteins V and W, known to counteract the host innate immunity. In the hamster animal model, CSUR381 induced lethal infections. Altogether, these data suggest that the Cambodia bat-derived NiV isolate has high pathogenic potential and, thus, provide insight for further studies and better risk assessment for future NiV outbreaks in Southeast Asia. [ABSTRACT FROM AUTHOR]

Aim: Farms that are neighboring wildlife sanctuaries are at risk of spillover infection from wildlife, and the objective of this research is to examine the species diversity of Malaysian fruit bats in livestock farm in determining the possible risk of spill over infection to livestock. Materials and Methods: Fifty individual fruit bats were captured using six mists net, from May to July 2017. The nets were set at dusk (1830 h) as bats emerge for foraging and monitored at every 30-min intervals throughout the night until dawn when they returned to the roost. The nets were closed for the day until next night, and captured bats were identified to species levels. Results: All the captured bats were mega chiropterans, and Cynopterus brachyotis was the highest captured species, representing 40% of the total capture. Shannon-Weiner index is 2.80, and Simpson index is 0.2. Our result suggests that there is a degree of species dominance with low diversity in Lenggong Livestock Breeding Center. Conclusion: We concluded that fruit bats are indeed, encroaching livestock areas and the species identified could be a potential source of infection to susceptible livestock. Hence, an active surveillance should be embarked on farms that border wildlife sanctuaries.

Aim: The impact of Pleistocene climatic oscillations on tropical biomes is associated with changes in the extent of forest cover. Fruit bats have played a role in woodland dynamics via pollination and seed dispersal. We hypothesized that phylogeographic patterns of Rousettus on continental Africa and adjacent islands should show a signature of pluvial‐drought cycles, involving demographic expansions and contractions. Location: Afrotropical, Malagasy and Saharo‐Arabian biogeographic realms. Taxon: Genus Rousettus (Pteropodidae). Methods: Phylogeographic and population genetic approaches using mitochondrial and microsatellite data were integrated with species distribution modelling of currently suitable habitats and those of the Last Glacial Maximum using climate simulations. Results: Phylogenetic reconstruction yielded an Asian outgroup followed by pectinate branching of the Indian Ocean taxa and Rousettus aegyptiacus. While nuclear microsatellites were homogeneous across the African mainland, two mitochondrial haplogroups were found. Haplogroup I is widespread in regions with extensive tree cover, including tropical rain forests, and has close relationships to isolated lineages in the Middle East and islands in the Gulf of Guinea. Haplogroup II is sister to the rest of the R. aegyptiacus radiation and is found in eastern and southern Africa and the Sudanian savanna in habitats with semi‐open land cover. Main Conclusion: Palaeodistributional modelling ascertained that the Indian Ocean islands provided more extensive areas of suitable habitat in the past relative to conditions today, suggesting stepping stone connectivity between Asia and Africa during Pleistocene interpluvial sea‐level lowstands. Inverse pluvial‐drought demography was detected in lineages ancestral to recent haplogroups, providing evidence of past forest refugia and complex ecogeographic scenarios of haplogroup origins involving allopatry and parapatry connected with the eastern Afromontane biodiversity hotspot, and subsequent admixture of nuclear gene pools. The Middle Eastern lineage probably originated during pluvial green Sahara periods, possibly in co‐evolution with ancestors of tree crop species domesticated later during the Neolithic revolution. The keystone role of rousettine bats for forest regeneration and their ability to pioneer dry and distant habitats emphasize their role in conservation biology and restoration ecology. [ABSTRACT FROM AUTHOR]

The biology and ecology of Africa’s largest fruit bat remains largely understudied and enigmatic despite at least two highly unusual attributes. The acoustic lek mating behavior of the hammer-headed bat (Hypsignathus monstrosus) in the Congo basin was first described in the 1970s. More recently molecular testing implicated this species and other African bats as potential reservoir hosts for Ebola virus and it was one of only two fruit bat species epidemiologically linked to the 2008 Luebo, Democratic Republic of Congo, Ebola outbreak. Here we share findings from the first pilot study of hammer-headed bat movement using GPS tracking and accelerometry units and a small preceding radio-tracking trial at an apparent lekking site. The radio-tracking revealed adult males had high rates of nightly visitation to the site compared to females (only one visit) and that two of six females day-roosted ~100 m west of Libonga, the nearest village that is ~1.6 km southwest. Four months later, in mid-April 2018, five individual bats, comprised of four males and one female, were tracked from two to 306 days, collecting from 67 to 1022 GPS locations. As measured by mean distance to the site and proportion of nightly GPS locations within 1 km of the site (percent visitation), the males were much more closely associated with the site (mean distance 1.4 km; 51% visitation), than the female (mean 5.5 km; 2.2% visitation). Despite the small sample size, our tracking evidence supports our original characterization of the site as a lek, and the lek itself is much more central to male than female movement. Moreover, our pilot demonstrates the technical feasibility of executing future studies on hammer-headed bats that will help fill problematic knowledge gaps about zoonotic spillover risks and the conservation needs of fruit bats across the continent. [ABSTRACT FROM AUTHOR]

Pathogen circulation among reservoir hosts is a precondition for zoonotic spillover. Unlike the acute, high morbidity infections typical in spillover hosts, infected reservoir hosts often exhibit low morbidity and mortality. Although it has been proposed that reservoir host infections may be persistent with recurrent episodes of shedding, direct evidence is often lacking. We construct a generalized SEIR (susceptible, exposed, infectious, recovered) framework encompassing 46 sub-models representing the full range of possible transitions among those four states of infection and immunity. We then use likelihood-based methods to fit these models to nine years of longitudinal data on henipavirus serology from a captive colony of Eidolon helvum bats in Ghana. We find that reinfection is necessary to explain observed dynamics; that acute infectious periods may be very short (hours to days); that immunity, if present, lasts about 1–2 years; and that recurring latent infection is likely. Although quantitative inference is sensitive to assumptions about serology, qualitative predictions are robust. Our novel approach helps clarify mechanisms of viral persistence and circulation in wild bats, including estimated ranges for key parameters such as the basic reproduction number and the duration of the infectious period. Our results inform how future field-based and experimental work could differentiate the processes of viral recurrence and reinfection in reservoir hosts. This article is part of the theme issue 'Dynamic and integrative approaches to understanding pathogen spillover'. [ABSTRACT FROM AUTHOR]

The Bonin flying fox (Pteropus pselaphon) is one of the most critically endangered species of animals. The number of this species is estimated to be around 150; being classified at the top rank in the list by International Union of Animal Conservation. Our group previously showed that expression of CDK4, CYCLIN D1, and telomerase reverse transcriptase (TERT) efficiently induce immortalization of human, bovine, swine, monkey, and buffalo-derived cells. In this manuscript, we successfully established the primary cells from Bonin flying fox. We introduced CDK4, CYCLIN D1, and TERT into the primary cells. The established cells showed efficient expression of introduced genes at the protein level. Furthermore, the established cells were free from senescence, indicating it reached to immortalization. Moreover, we showed that interspecies somatic cell nuclear transfer of Bonin flying fox derived cell into bovine embryo allowed the development of the embryo to 8 cell stages. Our established cell has the potential to contribute to species conservation. [ABSTRACT FROM AUTHOR]

The Mauritius fruit bat (Pteropus niger) has been the subject of repeated culling campaigns, apparently in response to pressure from the fruit-growing industry concerned over damage to commercially valuable orchard crops such as lychees. More than 31,000 fruit-bearing lychee trees also exist in private backyards, making this an issue pertinent to a wide cross-section of the Mauritian general public and not just those involved in commercial fruit production. The level of damage caused by bats to fruit crops is often debated and the low number of robust damage assessment studies hampers mitigation efforts. During the fruiting season of 2016/2017, we assessed the damage among backyard lychee trees attributable to fruit bats and other causes around Vacoas-Phoenix, Central Mauritius and evaluated the impact of using protective netting as a mitigation strategy. Fruit yield from panicles that were protected from depredation by nylon netting was approximately one third greater than that from unprotected panicles. We suspect that fruit bats were responsible for approximately 42% of the total damage but illustrate the difficulties in attributing damage to a single cause in such assessments. Although we demonstrate the value of protective netting, we recognize that barriers to implementation exist and that a more holistic approach that incorporates crop protection, forest restoration strategies and addresses negative public attitudes towards bats in general is required to ensure the persistence of this endemic species. [ABSTRACT FROM AUTHOR]

The 2018 outbreak of Nipah virus in Kerala, India, highlights the need for global surveillance of henipaviruses in bats, which are the reservoir hosts for this and other viruses. Nipah virus, an emerging paramyxovirus in the genus Henipavirus, causes severe disease and stuttering chains of transmission in humans and is considered a potential pandemic threat. In May 2018, an outbreak of Nipah virus began in Kerala, > 1800 km from the sites of previous outbreaks in eastern India in 2001 and 2007. Twenty-three people were infected and 21 people died (16 deaths and 18 cases were laboratory confirmed). Initial surveillance focused on insectivorous bats (Megaderma spasma), whereas follow-up surveys within Kerala found evidence of Nipah virus in fruit bats (Pteropus medius). P. medius is the confirmed host in Bangladesh and is now a confirmed host in India. However, other bat species may also serve as reservoir hosts of henipaviruses. To inform surveillance of Nipah virus in bats, we reviewed and analyzed the published records of Nipah virus surveillance globally. We applied a trait-based machine learning approach to a subset of species that occur in Asia, Australia, and Oceana. In addition to seven species in Kerala that were previously identified as Nipah virus seropositive, we identified at least four bat species that, on the basis of trait similarity with known Nipah virus-seropositive species, have a relatively high likelihood of exposure to Nipah or Nipah-like viruses in India. These machine-learning approaches provide the first step in the sequence of studies required to assess the risk of Nipah virus spillover in India. Nipah virus surveillance not only within Kerala but also elsewhere in India would benefit from a research pipeline that included surveys of known and predicted reservoirs for serological evidence of past infection with Nipah virus (or cross reacting henipaviruses). Serosurveys should then be followed by longitudinal spatial and temporal studies to detect shedding and isolate virus from species with evidence of infection. Ecological studies will then be required to understand the dynamics governing prevalence and shedding in bats and the contacts that could pose a risk to public health. [ABSTRACT FROM AUTHOR]

Bats are implicated as natural reservoirs for a wide range of zoonotic viruses including SARS and MERS coronaviruses, Ebola, Marburg, Nipah, Hendra, Rabies and other lyssaviruses. Accordingly, many One Health surveillance and viral discovery programs have focused on bats. In this report we present viral metagenomic data from bats collected in the Kingdom of Saudi Arabia [KSA]. Unbiased high throughput sequencing of fecal samples from 72 bat individuals comprising four species; lesser mouse-tailed bat (Rhinopoma hardwickii), Egyptian tomb bat (Taphozous perforatus), straw-colored fruit bat (Eidolon helvum), and Egyptian fruit bat (Rousettus aegyptiacus) revealed molecular evidence of a diverse set of viral families: Picornaviridae (hepatovirus, teschovirus, parechovirus), Reoviridae (rotavirus), Polyomaviridae (polyomavirus), Papillomaviridae (papillomavirus), Astroviridae (astrovirus), Caliciviridae (sapovirus), Coronaviridae (coronavirus), Adenoviridae (adenovirus), Paramyxoviridae (paramyxovirus), and unassigned mononegavirales (chuvirus). Additionally, we discovered a bastro-like virus (Middle East Hepe-Astrovirus), with a genomic organization similar to Hepeviridae. However, since it shared homology with Hepeviridae and Astroviridae at ORF1 and in ORF2, respectively, the newly discovered Hepe-Astrovirus may represent a phylogenetic bridge between Hepeviridae and Astroviridae. [ABSTRACT FROM AUTHOR]

The emergence of Zika virus (ZIKV) in the New World has led to more than 200,000 human infections. Perinatal infection can cause severe neurological complications, including fetal and neonatal microcephaly, and in adults there is an association with Guillain-Barré syndrome (GBS). ZIKV is transmitted to humans by Aedes sp. mosquitoes, yet little is known about its enzootic cycle in which transmission is thought to occur between arboreal Aedes sp. mosquitos and non-human primates. In the 1950s and ‘60s, several bat species were shown to be naturally and experimentally susceptible to ZIKV with acute viremia and seroconversion, and some developed neurological disease with viral antigen detected the brain. Because of ZIKV emergence in the Americas, we sought to determine susceptibility of Jamaican fruit bats (Artibeus jamaicensis), one of the most common bats in the New World. Bats were inoculated with ZIKV PRVABC59 but did not show signs of disease. Bats held to 28 days post-inoculation (PI) had detectable antibody by ELISA and viral RNA was detected by qRT-PCR in the brain, saliva and urine in some of the bats. Immunoreactivity using polyclonal anti-ZIKV antibody was detected in testes, brain, lung and salivary glands plus scrotal skin. Tropism for mononuclear cells, including macrophages/microglia and fibroblasts, was seen in the aforementioned organs in addition to testicular Leydig cells. The virus likely localized to the brain via infection of Iba1+ macrophage/microglial cells. Jamaican fruit bats, therefore, may be a useful animal model for the study of ZIKV infection. This work also raises the possibility that bats may have a role in Zika virus ecology in endemic regions, and that ZIKV may pose a wildlife disease threat to bat populations. [ABSTRACT FROM AUTHOR]

Flying foxes (family Pteropodidae) have distinct life histories given their size, characterized by longevity, low reproductive output, and long gestation. However, they tend to decouple the age at which sexual maturity is reached from the age at which they reach adult dimensions. We examined growth, maturation, and reproduction in the Critically Endangered Christmas Island flying fox (Pteropus natalis) to determine the timing of sex-specific life cycle events and patterns of growth. We estimated that juvenile growth in forearm length and body mass increased at a mean rate of 0.029 ± 0.005 mm/day and 0.33 ± 0.07 g/day for both males and females alike. Using these growth rates, we determined that the birth of pups occurs between December and March, with young becoming volant between June and August. The age at maturation for P. natalis is one of the oldest among all bat species. Juvenile males began to mature 15 months after birth and reached maturity 27 months after birth. Females reached maturity 24 months after birth at a significantly smaller body mass (3.6%) and forearm length (1.4%) than males. Significant sexual dimorphism and bimaturation was observed, with juvenile males being 1.5% and adult males being 1.9% larger on average than females for skeletal dimensions only. Growth and maturation are even slower in P. natalis than in the few other Pteropus species studied to date. The slow growth and delayed maturation of P. natalis imply slower potential population growth rates, further complicating the recovery of this Critically Endangered single-island endemic. [ABSTRACT FROM AUTHOR]

Bats are suspected to play important roles in the ecology of filoviruses, including ebolaviruses and marburgviruses. A cave-dwelling fruit bat, Rousettus aegyptiacus, has been shown to be a reservoir of marburgviruses. Using an enzyme-linked immunosorbent assay with the viral glycoprotein antigen, we detected immunoglobulin G antibodies specific to multiple filoviruses in 158 of 290 serum samples of R aegyptiacus bats captured in Zambia during the years 2014-2017. In particular, 43.8% of the bats were seropositive to marburgvirus, supporting the notion that this bat species continuously maintains marburgviruses as a reservoir. Of note, distinct peaks of seropositive rates were repeatedly observed at the beginning of rainy seasons, suggesting seasonality of the presence of newly infected individuals in this bat population. These data highlight the need for continued monitoring of filovirus infection in this bat species even in countries where filovirus diseases have not been reported. [ABSTRACT FROM AUTHOR]

A new site record for the Dobson‘s Long-tongued Fruit Bat Eonycteris spelaea (Pteropodidae, Chiroptera) is presented from Kerala, India. A revised distribution map of the species is also given. The morphometry of Eonycteris spelaea is discussed. DNA sequences have been deposited in GenBank.

Electrocution is one of the less known anthropogenic impacts likely affecting the bat population. We surveyed 925 km of overhead distribution power lines that supply energy to spreading urbanized areas in Sri Lanka, recording 300 electrocuted Indian flying foxes (Pteropus giganteus). Electrocutions were recorded up to 58 km from the nearest known colony, and all of them were in urbanized areas and very close ( X ¯ = 4.8 m) to the exotic fruiting trees cultivated in gardens. Predictable anthropogenic food subsidies, in the form of cultivated fruits and flowers, seem to attract flying foxes to urban habitats, which in turn become ecological traps given their high electrocution risk. However, electrocution rates greatly varied among the 352 power lines surveyed (0.00−24.6 indiv./km), being highest in power lines with four wires oriented vertically ( X ¯ = 0.92 indiv./km) and almost zero in power lines with wires oriented horizontally. Therefore, the latter design should be applied to projected new power lines and old vertically oriented lines in electrocution hotspots should be substituted. Given that flying foxes are key seed dispersers and pollinators, their foraging habitat selection change toward urban habitats together with high electrocution risk not only may contribute to their population decline but also put their ecosystem services at risk.

Elephants and fruit bats have evolved large brains even though they have lost a gene that is fundamental to the supply of energy to the brain when glucose is not available.

Apart from glucose, fatty acid-derived ketone bodies provide metabolic energy for the brain during fasting and neonatal development. We investigated the evolution of HMGCS2, the key enzyme required for ketone body biosynthesis (ketogenesis). Unexpectedly, we found that three mammalian lineages, comprising cetaceans (dolphins and whales), elephants and mastodons, and Old World fruit bats have lost this gene. Remarkably, many of these species have exceptionally large brains and signs of intelligent behavior. While fruit bats are sensitive to starvation, cetaceans and elephants can still withstand periods of fasting. This suggests that alternative strategies to fuel large brains during fasting evolved repeatedly and reveals flexibility in mammalian energy metabolism. Furthermore, we show that HMGCS2 loss preceded brain size expansion in toothed whales and elephants. Thus, while ketogenesis was likely important for brain size expansion in modern humans, ketogenesis is not a universal precondition for the evolution of large mammalian brains.