Carnivorous Bats Research Articles

A chromosome-level genome assembly of an avivorous bat species (Nyctalus aviator)

Currently, three carnivorous bat species, namely Ia io, Nyctalus lasiopterus, and Nyctalus aviator, are known to actively prey on seasonal migratory birds (hereinafter referred to as “avivorous bats”). However, the absence of reference genomes impedes a thorough comprehension of the molecular adaptations of avivorous bat species. Herein, we present the high-quality chromosome-scale reference genome of N. aviator based on PacBio subreads, DNBSEQ short-reads and Hi-C sequencing data. The genome assembly size of N. aviator is 1.77 Gb, with a scaffold N50 of 102 Mb, of which 99.8% assembly was anchored into 21 pseudo-chromosomes. After masking 635.1 Mb repetitive sequences, a total of 19,412 protein-coding genes were identified, of which 99.3% were functionally annotated. The genome assembly and gene prediction reached 96.1% and 96.1% completeness of Benchmarking Universal Single-Copy Orthologs (BUSCO), respectively. This chromosome-level reference genome of N. aviator fills a gap in the existing information on the genomes of carnivorous bats, especially avivorous ones, and will be valuable for mechanism of adaptations to dietary niche expansion in bat species.

Comparative genomics reveals convergent adaptations in lipid metabolism and low genetic diversity in carnivorous bats

AbstractDietary specialization stands as a major factor in the study of adaptive evolution and the field of conservation biology among animals. Although bats show unparalleled dietary diversification among mammals, specialized carnivory remains relatively rare within this group. Consequently, our comprehension of the genetic and conservation aspects associated with this specific dietary niche in bats has largely remained uncharted. To investigate molecular adaptations and conservation genetics in carnivorous bats, we produced a new draft genome assembly for the carnivorous bat Vampyrum spectrum. Furthermore, we utilized this genome alongside another distantly related carnivorous bat Megaderma lyra, to conduct genome‐wide comparative analyses with other bat species. Our findings unveil that genes linked to lipid metabolism exhibit signatures of positive selection and convergent molecular adaptation in the two divergent lineages of carnivorous bats. Intriguingly, we have uncovered that the evolution of dietary specialization in carnivorous bats is accompanied by molecular adaptations acting on genes in the peroxisome proliferator‐activated receptors pathways, which are crucial in regulating plasma lipid metabolism and sustaining lipid homeostasis. Additionally, our genomic analyses also reveal low genetic diversity in both carnivorous bat species. This pattern is attributed to their continuously declining population sizes and low levels of heterozygosity, signaling their vulnerability and emphasizing the pressing need for conservation efforts. These genomic discoveries advance our understanding of genetic underpinnings of carnivory in bats and underscore substantial conservation concerns associated with carnivorous bat species.

Variable shifts in bird and bat assemblages as a result of reduced‐impact logging revealed after 10 years

Abstract Selective logging is the most widespread driver of land‐use change in biodiverse and carbon‐rich tropical forests. However, the effects of selective logging on biodiversity are less than those associated with other drivers of forest degradation. A suite of recent research has shown that reduced‐impact logging (RIL) results in few or no changes to biological assemblages. But because this logging technique is relatively new, most studies have only considered short‐term impacts. We address this research gap by quantifying changes in biodiversity assemblage as a result of RIL over the longer term. We comprehensively sampled bird and bat assemblages pre‐logged, 1 year after, and 10 years after RIL in Guyana, using a before‐after control‐impact (BACI) sampling design. We compared bird and bat assemblages in each timeframe, and additionally appraised the impact of time since logging, and the number of trees harvested across the suite of species which we further divided between different feeding guilds, disturbance sensitivity and vertical stratification of forest use. We found that 1 year after logging only minor changes could be detected, but 10 years later richness had slightly declined in some groups, while others had shown complete recovery. Nectivorous and insectivorous birds, and carnivorous bats declined in richness, while carnivorous birds, showed a clear recovery to a state akin to pre‐logging. This indicates that for some niches a subtle, but long‐term relaxation effect may be occurring, whereby extinction debts are realized long after the initial disturbance, while other groups have either recovered or not changed after logging. Assemblage changes were also predicted by vertical stratification of forest use, with avian species using the understorey and mid–upper levels of the forest being most affected. Synthesis and applications: Our study demonstrates how best practice forestry and logging can maintain healthy vertebrate populations over the long term. Forestry concessions that adopt techniques of low‐harvest RIL and are managed for their long‐term timber provision through extension of regeneration times beyond 10 years after harvest, are likely to benefit from the ecosystem services provided by biodiversity, while also making a valuable contribution to the global conservation estate.

The complete mitochondrial genome of the Australian ghost bat Macroderma gigas

The Ghost bat Macroderma gigas is a monotypic bat species that is endemic to northern Australia and named on the basis of the large size of its partially conjoined ears. It is the only carnivorous bat found in Australia and its conservation status is currently listed as Vulnerable. Here, we describe the complete mitochondrial genome of M. gigas and compare it to other vertebrates. The M. gigas circularized mitogenome was 16,661 bp and contained 13 protein-coding genes, two rRNA genes, 22 tRNAs and a control region (D-loop) of 1228 bp. Phylogenetic analysis of available entire mitogenomes reveals that Macroderma gigas is most closely related to the Indian false vampire bat Megaderma lyra in the family Megadermatidae (false vampire bats).

Dietary and body-mass reconstruction of the Miocene neotropical batNotonycteris magdalenensis(Phyllostomidae) from La Venta, Colombia

AbstractWith 14 species recorded, the Miocene La Venta bat fauna is the most diverse bat paleocommunity in South America. It includes the oldest plant-visiting bat in the New World and some of the earliest representatives of the extant families Phyllostomidae, Thyropteridae, and Noctilionidae. La Venta'sNotonycteris magdalenensisis an extinct member of the subfamily Phyllostominae, a group of modern Neotropical animalivorous bats, and is commonly included in studies of the evolution of Neotropical bats, but aspects of its biology remain unclear. In this study, we used multivariate dental topography analysis (DTA) to reconstruct the diet ofN. magdalenensisby quantitatively comparing measures of molar complexity with those of 25 modern noctilionoid species representing all major dietary habits in bats. We found clear differences in molar complexity between dietary guilds, indicating that DTA is potentially an informative tool to study bat ecomorphology. Our results suggestN. magdalenensiswas probably an omnivore or insectivore, rather than a carnivore like its modern relativesChrotopterus auritusandVampyrum spectrum. Also, we reconstructed the body mass ofN. magdalenensisto be ~95 g, larger than most insectivorous bats, but smaller than the largest carnivorous bat (V. spectrum). Our results confirm thatN. magdalenensiswas not a specialized carnivore. It remains to be demonstrated that the specialized carnivory ecological niche was occupied by the same lineage of phyllostomines from at least the middle Miocene. Combining our diet and body-mass reconstructions, we suggest thatN. magdalenensisexhibits morphological pre-adaptations crucial for the evolution of specialized carnivory.

We eat meat: a review of carnivory in bats

Abstract Some bat species in the families Phyllostomidae, Megadermatidae, and Nycteridae have long been known to consume terrestrial vertebrates and, more recently, reports of aerial‐hawking vespertilionid carnivores have surfaced. We review the diets, hunting behaviour and roosting ecology of 17 bat species that are known to consume terrestrial vertebrates: Vampyrum spectrum, Chrotopterus auritus, Trachops cirrhosus, Macroderma gigas, Megaderma (Lyroderma) lyra, Nycteris grandis, Nyctalus lasiopterus, Nyctalus aviator, Ia io, Antrozous pallidus, Cardioderma cor, Phyllostomus hastatus, Mimon (Gardnerycteris) crenulatum, Mimon cozumelae, Tonatia saurophila, Tonatia bidens, and Lophostoma silvicolum. Data on their diet and roosts were obtained from 241 original works, with considerable differences in the amount of research and information available among species. Carnivorous bats were found to belong to an ecologically diverse group and share little but their diet. Therefore, we define a carnivorous bat as a bat that, either year‐round or seasonally, uses terrestrial vertebrates as the main component of its diet, at least in part of its geographic range. We conclude from available data that Mimon crenulatum, Lophostoma silvicolum, Mimon cozumelae, Phyllostomus hastatus, Tonatia bidens, Tonatia saurophila, Cardioderma cor, and Antrozous pallidus use vertebrates as a minor part of their diet and should not be considered carnivorous. The nine other species we reviewed do fit into the definition of carnivorous bats, and can be further subdivided based on their ecology and the seasonality of their habits into three categories: year‐round predominantly gleaning carnivores (Chrotopterus auritus, Trachops cirrhosus, and Vampyrum spectrum), seasonal predominantly gleaning carnivores (Megaderma lyra, Macroderma gigas, and Nycteris grandis) and seasonal aerial‐hawking bird‐eating carnivores (Ia io, Nyctalus aviator, and Nyctalus lasiopterus).

A REVIEW ON USE OF BIOACOUSTICS FOR DETECTION, MONITORING AND MANAGEMENT OF INSECT PESTS

Forest and agro-ecosystems are the main natural bioresources which provides support to human livelihoods. ‘Indian False Vampire bats’ are the important components of these ecosystems as primary consumers of large sized nocturnal insects and small vertebrates, there by fulfill key ecosystem services as bio-control agents. Flight has enabled them to exploit a variety of foraging niches inaccessible to other mammals. Ecomorphological and the dietary selection study on false vampire bats suggest they are the carnivorous bats and perform crucial role as pest managers in the ecosystem. The nocturnal foraging behaviour, echolocation capability, dentition and flight manoeuvrability of these bat species are the adaptations that enhance their ability to capture nocturnal prey items. Undoubtedly, they are the most gregarious and successful group of beneficial animals to the ecosystem. Their population should be preserved for the benefit to conserve sustainable development of the ecosystem. The Indian false vampire bat conservation will not only replenish the ecosystem but also aid the forest floral health management and reduce the usage of pesticides in the agro ecosystem. Key words: Ecosystems, Bio-control agents, Foraging niches, False vampire, Health management

Trophic guild and forest type explain phyllostomid bat abundance variation from human habitat disturbance

The loss of tropical forest cover caused by land-use change is causing changes in populations of animal trophic guilds, including those belonging to Phyllostomidae bat species. They fulfill important ecosystem functions such as pollination, seed dispersion, and regulations of vertebrate and invertebrate populations in Neotropical forests and human disturbed habitats. However, the effect of habitat disturbance on the abundance of phyllostomid bats is still controversial, and it is unknown if this effect presents a phylogenetic signal, or if this abundance is influenced by the type of forest where the disturbance occurs or by the distance between disturbed habitat and conserved forest. In order to answer these new questions, an exhaustive literature review was performed followed by a series of meta-analyzes. We found 26 studies from which 829 cases (i.e. species observations; k) were extracted. Each case reported the number of individuals captured in the disturbed habitat and in the conserved forest. As effect size, the bat proportion in disturbed habitats was used. We did not use phylogenetic correction in the meta-analysis because we did not find a phylogenetic signal in the bat proportion in disturbed habitats. We found that omnivorous, carnivorous, insectivorous and hematophagous bats were sensitive to habitat disturbance, while phytophagous were tolerant. In addition, the type of habitat disturbance and the type of forest where it occurs explain the differences of bat abundance within each trophic guild. Finally, there was no effect of the type of crop, the age of the secondary forest, and the distance to a conserved forest on trophic guild bat abundance in disturbed habitats. These results could focus the conservation efforts of phyllostomid bats and the ecosystem services they provide in both anthropogenic and conserved habitats.

Mercury bioaccumulation in tropical bats from a region of active artisanal and small-scale gold mining.

Mercury negatively affects human and animal health. Artisanal and small-scale gold mining can be a major local source of mercury contamination, especially into aquatic systems in tropical areas. Animals associated with mercury-contaminated aquatic systems are at high risk of experiencing effects of this heavy metal, but it is not clear how far the effects may extend into nearby terrestrial systems. We report mercury contamination levels in bats in agricultural areas at increasing distances from gold mining (~3-89 km of distance). We hypothesized that bat mercury concentrations would differ between feeding guilds, land use types, and be higher at sites closer to gold mining areas. We collected 112 fur samples from 30 bat species and eight guilds, and provide the first reports of concentrations in 12 species. All mercury concentrations were below the level at which health is likely to be affected (10 ppm). We found guild-influenced differences among mercury concentration levels, with the highest concentrations in aerial insectivores and carnivores, and the lowest in canopy frugivores. Our results suggest insectivorous and carnivorous bats may still be at some risk even at sites distant from aquatic mercury contamination. We did not find an effect of agricultural land-use type on mercury concentrations within species or guilds, suggesting mercury contamination did not extend to agricultural sites from areas of gold mining activities, and that these agricultural activities themselves were not an important source of mercury. We conclude bats did not demonstrate a signature of mercury risk either as a result of proximity of gold mining, or as a result of agricultural activities.

State-dependent learning influences foraging behaviour in an acoustic predator

Humans and other animals have been shown to exhibit preferences for options previously associated with greater past need. Such studies indicate that animals are sensitive to both the physical properties of choices and their own state-dependent gains at the time of learning. Because this behaviour appears to occur across divergent taxonomic groups, it most likely reflects a common way that animals learn about food. Here we study this phenomenon in the frog-eating bat, Trachops cirrhosus. This carnivorous bat hunts by eavesdropping on frog and insect mating calls and its diet is both broad and seasonally variable. As a result, these bats must learn about new sources of food and possibly the state-dependent gains associated with those sources. In this experiment we trained bats to associate two different acoustic cues (ringtones) to two identical food rewards. Each ringtone was encountered in one of two nutritional states: hungry or pre-fed. We then tested preferences between these cues under both nutritional states. We found that bats overwhelmingly preferred the ringtone associated with previous greater deprivation regardless of their condition during testing. We argue that it is most likely adaptive for frog-eating bats to place a higher value on food rewards that are obtained when internal reserves are low.

Correlation of skull morphology and bite force in a bird-eating bat (Ia io; Vespertilionidae)

BackgroundGenetic and ecological factors influence morphology, and morphology is compatible with function. The morphology and bite performance of skulls of bats show a number of characteristic feeding adaptations. The great evening bat, Ia io (Thomas, 1902), eats both insects and birds (Thabah et al. J Mammal 88: 728-735, 2007), and as such, it is considered to represent a case of dietary niche expansion from insects to birds. How the skull morphology or bite force in I. io are related to the expanded diet (that is, birds) remains unknown. We used three-dimensional (3D) geometry of the skulls and measurements of bite force and diets from I. io and 13 other species of sympatric or closely related bat species to investigate the characteristics and the correlation of skull morphology and bite force to diets.ResultsSignificant differences in skull morphology and bite force among species and diets were observed in this study. Similar to the carnivorous bats, bird-eaters (I. io) differed significantly from insectivorous bats; I. io had a larger skull size, taller crania, wider zygomatic arches, shorter but robust mandibles, and larger bite force than the insectivores. The skull morphology of bats was significantly associated with bite force whether controlling for phylogeny or not, but no significant correlations were found between diets and the skulls, or between diets and residual bite force, after controlling for phylogeny.ConclusionsThese results indicated that skull morphology was independent of diet, and phylogeny had a greater impact on skull morphology than diet in these species. The changes in skull size and morphology have led to variation in bite force, and finally different bat species feeding on different foods. In conclusion, I. io has a larger skull size, robust mandibles, shortened dentitions, longer coronoid processes, expanded angular processes, low condyles, and taller cranial sagittal crests, and wider zygomatic arches that provide this species with mechanical advantages; their greater bite force may help them use larger and hard-bodied birds as a dietary component.

Movement ecology of the carnivorous woolly false vampire bat (Chrotopterus auritus) in southern Mexico.

Deforestation is a critical threat to bats. The woolly false vampire bat Chrotopterus auritus is a carnivorous bat that is both an indicator species for well-conserved forests and a threatened species in Mexico and other countries due to deforestation. We currently lack the information needed to assess the effects of forest fragmentation and destruction on their populations and to develop plans for their conservation. We used GPS loggers to study the movement patterns of C. auritus in southern Mexico. We observed 72 foraging nights by GPS-tagging 10 individuals from two colonies on 32 occasions in a highly disturbed heterogeneous landscape with extensive deforestation (Hormiguero), and in a more homogeneous, well-preserved forested landscape (Monterrey). Tracked false vampire bats averaged a home range of 108.24 ha, a core foraging area of 3.78 ha and average maximum flight distances of 2.06 km. The bats ranged farther and flew significantly longer distances in Hormiguero than in Monterrey, with males flying longer and more variable distances. They used the well-preserved semi-deciduous forest more often than secondary forest and agricultural fields for traveling and foraging, but the bats occasionally moved and hunted along the borders of secondary forest and agricultural fields adjacent to semi-deciduous conserved forest areas. Although this carnivorous bat might cope with some fragmentation, we suggest that large well-preserved forested areas are highly important for its conservation.

No lunar phobia in insectivorous bats in Kenya

We monitored foraging insectivorous bats along walked transects in forest and farmland at Arabuko-Sokoke Forest in coastal Kenya, using a heterodyne bat detector. The main purpose was to test whether aerial-hawking insectivorous bats that feed in open places (in this case mostly Scotophilus and Scotoecus spp.) show lunar phobia, i.e. restricting their activity on moonlit nights. Such behavior would be an expected response to the threat posed by visually oriented aerial predators such as bat hawks, owls and carnivorous bats. The occurrence of lunar phobia in bats is a controversial issue and may have implications for how bats will be affected by increasing light pollution. Our results show that foraging activity of the bats that we studied was related to time of day, season, and habitat, albeit with no additional effect of moonlight discernable. We therefore conclude that foraging activity occurs independently of moonlight. This result is partly at odds with previous findings including predictions from a meta-analysis of lunar phobia in bats, which indicates that lunar phobia is common in these animals, though most likely to be present in tropical species that feed in open situations near vegetation and over water. Equally, our results conform to findings from studies of aerial insectivorous bats in tropical as well as temperate areas, most of which have failed to reveal any clear evidence of lunar phobia. We believe that moonlight generally does not facilitate aerial predation on flying bats in open situations, or, alternatively, the bats accept increased predation pressure while they fulfil the energetic requirements through hunting.

Hologenomic adaptations underlying the evolution of sanguivory in the common vampire bat

Adaptation to specialized diets often requires modifications at both genomic and microbiome levels. We applied a hologenomic approach to the common vampire bat (Desmodus rotundus), one of the only three obligate blood-feeding (sanguivorous) mammals, to study the evolution of its complex dietary adaptation. Specifically, we assembled its high-quality reference genome (scaffold N50 = 26.9 Mb, contig N50 = 36.6 kb) and gut metagenome, and compared them against those of insectivorous, frugivorous and carnivorous bats. Our analyses showed a particular common vampire bat genomic landscape regarding integrated viral elements, a dietary and phylogenetic influence on gut microbiome taxonomic and functional profiles, and that both genetic elements harbour key traits related to the nutritional (for example, vitamin and lipid shortage) and non-nutritional (for example, nitrogen waste and osmotic homeostasis) challenges of sanguivory. These findings highlight the value of a holistic study of both the host and its microbiota when attempting to decipher adaptations underlying radical dietary lifestyles.

Go big or go fish: morphological specializations in carnivorous bats.

Specialized carnivory is relatively uncommon across mammals, and bats constitute one of the few groups in which this diet has evolved multiple times. While size and morphological adaptations for carnivory have been identified in other taxa, it is unclear what phenotypic traits characterize the relatively recent evolution of carnivory in bats. To address this gap, we apply geometric morphometric and phylogenetic comparative analyses to elucidate which characters are associated with ecological divergence of carnivorous bats from insectivorous ancestors, and if there is morphological convergence among independent origins of carnivory within bats, and with other carnivorous mammals. We find that carnivorous bats are larger and converged to occupy a subset of the insectivorous morphospace, characterized by skull shapes that enhance bite force at relatively wide gapes. Piscivorous bats are morphologically distinct, with cranial shapes that enable high bite force at narrow gapes, which is necessary for processing fish prey. All animal-eating species exhibit positive allometry in rostrum elongation with respect to skull size, which could allow larger bats to take relatively larger prey. The skull shapes of carnivorous bats share similarities with generalized carnivorans, but tend to be more suited for increased bite force production at the expense of gape, when compared with specialized carnivorans.

A General History of Quadrupeds: The Figures Engraved on Wood by Thomas Bewick (review)

Reviewed by: A General History of Quadrupeds: The Figures Engraved on Wood by Thomas Bewick Swann Paradis Translated by Jamie McLennan Thomas Bewick, A General History of Quadrupeds: The Figures Engraved on Wood. Foreword by Yann Martel (Chicago: The University of Chicago Press, 2009). Pp. 544, 200 illus. $59.00 (cloth), $19.00 (paper), $7.00–$18.00 (e-book). Thomas Bewick (1753–1828), the master illustrator and wood engraver from Newcastle upon Tyne, is known primarily for his History of British Birds (1797–1804), which inspired John James Audubon in 1829 to name a species of wren after the artist (Bewick’s Wren [Thryomanes bewickii]); the following year, William Yarrell bestowed a similar honor in naming Bewick’s Swan (Cygnus bewickii). Astute readers may also recall the passage in the first chapter of Charlotte Brontë’s Jayne Eyre in which the young eponymous heroine delights in Bewick’s description of the “haunts of sea-fowl” on the Norwegian coast. Less well known is Bewick’s A General History of Quadrupeds. Published in 1790, the work appeared two years after the death of the celebrated French naturalist Georges-Louis Leclerc, Count of Buffon (1707–1788). Buffon’s Histoire naturelle, published by the Imprimerie royale, had been a veritable best-seller since 1749, with its thirty-six in-quarto volumes translated into several languages, including English and Dutch. When Bewick undertook to provide his own illustrated guide for English readers, which he hoped would be the most complete and “scientifically” accurate work at the time, he could not have ignored the volume of naturalist knowledge that Buffon had produced over the previous four decades. The manner in which Bewick refers to the author of Histoire naturelle is therefore somewhat puzzling. His explicit references are primarily limited to the titles of Buffon’s articles on animal descriptions, and these include several spelling errors that betray a less than perfect mastery of the French language: “Le Dain [sic]” (143); “Le Glutton [sic]” (285); “Le Poulatouche [sic]” (394). A General History of Quadrupeds [End Page 79] also contains a few obvious mistranslations, such as when Bewick offers “The Wallachian Sheep” (73) as the English equivalent of an enigmatic “Chevre de Crete [sic]”—a perplexing oversight, since the naturalist from Montbard had clearly specified in the third volume of the Supplément à l’Histoire naturelle (1776) that a drawing depicting this ovine species (“Valachian Eve [sic]”), sent by one Mr. Colinson of the Royal Society of London, had served as a model for Jacques De Sève’s plate VIII entitled “Brebis valachienne” (SHN, 3: 74). In this instance, Bewick not only displays poor translation skills, he commits an inexcusable interspecific error by transforming a sheep into a goat. He repeats the offence when he offers “Ternate bat” (518) as the English term not only for Linnaeus’s “Vespertilio Vampyrus”—a carnivorous bat that feeds on blood—but also for Buffon’s innocuous, fruit-eating “Roussette.” Many of the texts in Bewick’s work are implicit, rather dry translations of Buffon’s own preambles: see, for example, “The Horse” (1); “The Camel” (150); “The Elephant” (186); “The Tiger” (206); and “The Mole” (413). A General History of Quadrupeds contains approximately two hundred engravings, and here it can be said that Bewick raised the art of wood engraving to new heights. He worked with hardwood, engraving “with the grain” and employing fine tools similar to those used in metal engraving. Nevertheless, the images fall short artistically and scientifically, especially when compared with the plates of Buffon’s Histoire naturelle and notwithstanding the claims of the editor, who praises, on the back cover of this reprint, the English engraver as “one whose influence on natural history and book printing still endures today.” A few examples bear mentioning: the hindquarters of the “Lancashire Ox” (35) are depicted at far too steep an angle; the proportions of the giraffe’s neck are less than precise (“The Cameleopard” [118]); the head on “The Sloth” (496) resembles a copy of a Renaissance drawing; and “The Orang-Outang” displays a distinctly humanized posture, reflecting the fact that “The Wild Man of the Woods” (452) was still being used as a synonymous expression...

Do predators influence the behaviour of bats?

Many aspects of animal behaviour are affected by real-time changes in the risk of predation. This conclusion holds for virtually all taxa and ecological systems studied, but does it hold for bats? Bats are poorly represented in the literature on anti-predator behaviour, which may reflect a lack of nocturnal predators specialized on bats. If bats actually experience a world with minimal anti-predator concerns, then they will provide a unique contrast within the realm of vertebrate ecology. Alternatively, such predator-driven behaviour in bats may not yet be fully understood, given the difficulties in working with these highly mobile and nocturnal animals. We provide a wide-ranging exploration of these issues in bat behaviour. We first cover the basic predator-prey information available on bats, both on potential predators and the ways in which bats might perceive predators and respond to attacks. We then cover work relevant to key aspects of bat behaviour, such as choice of daytime roosts, the nature of sleep and torpor, evening roost departures, moonlight avoidance, landscape-related movement patterns, and habitat selection. Overall, the evidence in favour of a strong influence of predators on bat behaviour is equivocal, with the picture clouded by contradictory results and a lack of information on potential predators and the perception of risk by bats. It seems clear that day-active bats run a considerable risk of being killed by diurnal raptors, which are able to capture bats with relative ease. Thus, bats taking advantage of a pulse of insects just prior to sunset are likely taking risks to gain much-needed energy. Further, the choice of daytime roosts by bats is probably strongly influenced by roost safety. Few studies, however, have directly addressed either of these topics. As a group, insectivorous temperate-zone bats show no clear tendency to avoid apparently risky situations, such as activity on moonlit nights. However, some observations are consistent with the idea that predation risk affects choice of movement paths and feeding areas by temperate-zone bats, as well as the timing of roost departures. The behaviour of tropical bats, on the other hand, seems more generally influenced by predators; this is especially true for tropical nectarivores and frugivores, but also for insectivorous bats. Presumably there are more serious predators on bats in the tropics (e.g. specialized raptors or carnivorous bats), but the identity of these predators is unclear. More information is needed to assess fully the influence of predators on bat behaviour. There is much need for work on the ways in which bats perceive predators via auditory, visual, and olfactory cues, and whether bats have some knowledge of the risks posed by different predators. Also needed is information on how predators attack bats and how bats react to attacking predators. Difficult to obtain, but of critical value, will be information on the nature of the predation risk experienced by bats while away from roosts and during the full darkness of night.

All You Can Eat: High Performance Capacity and Plasticity in the Common Big-Eared Bat, Micronycteris microtis (Chiroptera: Phyllostomidae)

Ecological specialization and resource partitioning are expected to be particularly high in the species-rich communities of tropical vertebrates, yet many species have broader ecological niches than expected. In Neotropical ecosystems, Neotropical leaf-nosed bats (Phyllostomidae) are one of the most ecologically and functionally diverse vertebrate clades. Resource partitioning in phyllostomids might be achieved through differences in the ability to find and process food. We selected Micronycteris microtis, a very small (5–7 g) animalivorous phyllostomid, to explore whether broad resource use is associated with specific morphological, behavioral and performance traits within the phyllostomid radiation. We documented processing of natural prey and measured bite force in free-ranging M. microtis and other sympatric phyllostomids. We found that M. microtis had a remarkably broad diet for prey size and hardness. For the first time, we also report the consumption of vertebrates (lizards), which makes M. microtis the smallest carnivorous bat reported to date. Compared to other phyllostomids, M. microtis had the highest bite force for its size and cranial shape and high performance plasticity. Bite force and cranial shape appear to have evolved rapidly in the M. microtis lineage. High performance capacity and high efficiency in finding motionless prey might be key traits that allow M. microtis, and perhaps other species, to successfully co-exist with other gleaning bats.

New polymorphic microsatellite markers in the greater false vampire bat Megaderma lyra (Chiroptera: Megadermatidae)

In this study, we present 10 new microsatellite markers for a carnivorous bat, Megaderma lyra (family Megadermatidae). Out of 10 loci, only one locus showed a statistically significant value (P < 0.05) for FIS coefficient, and one was found to be X-linked. These loci were tested on 189 individuals representing four populations from southern India, and all loci were highly polymorphic. The mean number of observed alleles per locus was 10.1 (range from 6 to 16). Expected heterozygosity values ranged from 0.54 to 0.91. These polymorphic markers will be used to examine population structure, mating and dispersal behaviour of M. lyra in the field.

Highly structured fission–fusion societies in an aerial-hawking, carnivorous bat

In some group-living animals, societies are far from being static but are instead dynamic entities encompassing multiple scales of organization. We found that maternity colonies of giant noctule bats, Nyctalus lasiopterus, form fissionefusion societies, where group composition in single tree roosts changes on a daily basis but social cohesion in the larger group is preserved. The population inside a small city park was comprised of three distinct but cryptic social groups coexisting in close proximity. Each social group used a distinct roosting area, but some overlap existed in the boundaries between them. Social groups were stable at least in the mid term because adult females were loyal to roosting areas and young females returned to their natal social groups in successive years. Our results suggest that distinct social groups with separate roosting areas may have existed for at least 14 years. The findings described support the hypothesis that roost-switching behaviour in forest bats permits the maintenance of social bonds between colony members and enhances knowledge about a colony’s roosting resources. Fissionefusion societies in forest bats might have evolved as a mechanism to cope with changing conditions in the environment by restructuring subgroups or adjusting subgroup size, to maximize the amount of information that can be transferred between colony members, or as a consequence of territory inheritance by philopatric female offspring. Other factors such as resource competition or kin selection could limit the size and composition of fissionefusion societies and promote strong social structuring within populations.