Wing Membrane Research Articles

The Occurrence of Skin Mites from the Demodecidae and Psorergatidae (Acariformes: Prostigmata) Families in Bats, with a Description of a New Species and New Records.

Simple SummaryThis paper describes a new species, Demodex pusillus, inhabiting the hairy skin of Nyctalus noctula, which is one of the smallest arthropods. New data on the coexistence of skin mites from the sister families Demodecidae and Psorergatidae in bats are also included, as well as an updated global checklist and data on their occurrence, including location (topography) within the hosts.The bat skin mites from the closely-related Demodecidae and Psorergatidae families occur synhospitally, populating the same host species and perhaps neighboring microhabitats. However, data on their occurrence and parasitism are fragmentary and dispersed. Thus far, 27 Demodecidae and 18 Psorergatidae species have been described, but the coexistence of mites from both families was only demonstrated in six species of bats. This article presents a description of Demodex pusillus sp. nov. from Nyctalus noctula, including a new host record (first observation of demodecid mites in Nyctalus) and a new record concerning the occurrence of Psorergatoides kerivoluae in Plecotus auritus. It also includes an updated global checklist of the occurrence of Demodecidae and Psorergatidae in Chiroptera, including data on their records/distribution and location in their hosts. In both studied families, the mites exhibit preferences, and even topographic specificity, colonizing different microhabitats in the host, including the eye region (e.g., Meibomian glands of the eyes, corneal surface and eyelid vault), wing membranes and hairy skin on the body. Such colonization of separate microhabitats enables different species to co-occur within the same host, while the total number of parasites determines the level of parasite load, with higher levels being associated with the incidence of disease symptoms. It is worth mentioning that Demodex pusillus sp. nov. is the smallest known representative of the Demodecidae family and one of the smallest animals (70–80 micrometers in length).

Evaluation of Virus-Free and Wild-Type Isolates of Pseudogymnoascus destructans Using a Porcine Ear Model.

ABSTRACTWhite-nose syndrome (WNS), responsible for the mass mortality of North American bats, lacks economically viable and practical in vitro models for Pseudogymnoascus destructans infection, the causative agent of WNS. Not only are many susceptible North American insectivorous bats nearing extinction and, thus, scarce for experimental studies, but they are difficult to care for and maintain in captivity because of their specialized habitats and diets. In this study, we explored porcine ears as a potential substrate for studying infection development and the dynamics of P. destructans growth in the laboratory. Porcine ear skin shares many tissue-level similarities with bat skin and is a readily available resource. We found the porcine ear model provided a substrate faithfully mimicking external P. destructans colony morphology and internal histology similar to what is seen with P. destructans infections in bat wing membranes. This model provided a major advance by distinguishing virulence attributes between a wild-type Pseudogymnoascus destructans strain harboring a partitivirus common to all North American strains of the fungus and an isogenic virus-cured P. destructans strain. ImageJ analysis showed that the cured P. destructans strain was reduced significantly in ability to produce hyphal cover and showed less spore production on porcine skin. Taken together, these results strengthen our previous finding that the partitivirus infection has a role in WNS and provides a valuable model host tool in understanding P. destructans virulence factors for therapeutic application.IMPORTANCE This work describes an important insight into the role of Pseudogymnoascus destructans partitivirus in fungal biology and provides a model system for studying white-nose syndrome in bats, which has decimated North American populations.

Morphological features of Pipistrellus nathusii from the eastern part of its range (Middle Volga region)

A study was carried out on the morphometric parameters of regional samples of Pipistrellus nathusii populations from the Middle Volga region, which is the eastern part of the species’ range. In general, metric characters are typical of those of the species; clear differences were found by the colouration of wing membranes. The right-bank sample corresponds to the typical (northern, forest) form of P. nathusii. The left-bank (eastern) sample corresponds to the more southern and steppe form, which is characterized by a light tone of coat and a well-defined narrow white stripe on the edge of the wing, which is designated as colour type pargaré. Obviously, this feature of colouration is a marker of the most southeastern P. nathusii. Moreover, this feature characterizes the whole group of pipistrelles and is well known for the desert form of P. pipistrellus bactrianus, and is most pronounced in the eastern P. kuhlii lepidus. Original data on cases of detection pangaré-type depigmentation in other species of bats in the Volga region are noted (Vespertilio murinus and Myotis daubentonii). Thus, the pangaré-type colour of wing membranes in different bat species is a regional trait. In general, this is in line with Gloger’s ecogeographic rule of ligher colouration in arid conditions.A study was carried out on the morphometric parameters of regional samples of Pipistrellus nathusii populations from the Middle Volga region, which is the eastern part of the species’ range. In general, metric characters are typical of those of the species; clear differences were found by the colouration of wing membranes. The right-bank sample corresponds to the typical (northern, forest) form of P. nathusii. The left-bank (eastern) sample corresponds to the more southern and steppe form, which is characterized by a light tone of coat and a well-defined narrow white stripe on the edge of the wing, which is designated as colour type pargaré. Obviously, this feature of colouration is a marker of the most southeastern P. nathusii. Moreover, this feature characterizes the whole group of pipistrelles and is well known for the desert form of P. pipistrellus bactrianus, and is most pronounced in the eastern P. kuhlii lepidus. Original data on cases of detection pangaré-type depigmentation in other species of bats in the Volga region are noted (Vespertilio murinus and Myotis daubentonii). Thus, the pangaré-type colour of wing membranes in different bat species is a regional trait. In general, this is in line with Gloger’s ecogeographic rule of ligher colouration in arid conditions.

Efficiency and Aerodynamic Performance of Bristled Insect Wings Depending on Reynolds Number in Flapping Flight

Insect wings are generally constructed from veins and solid membranes. However, in the case of the smallest flying insects, the wing membrane is often replaced by hair-like bristles. In contrast to large insects, it is possible for both bristled and membranous wings to be simultaneously present in small insect species. There is therefore a continuing debate about the advantages and disadvantages of bristled wings for flight. In this study, we experimentally tested bristled robotic wing models on their ability to generate vertical forces and scored aerodynamic efficiency at Reynolds numbers that are typical for flight in miniature insects. The tested wings ranged from a solid membrane to a few bristles. A generic lift-based wing kinematic pattern moved the wings around their root. The results show that the lift coefficients, power coefficients and Froude efficiency decreased with increasing bristle spacing. Skin friction significantly attenuates lift production, which may even result in negative coefficients at elevated bristle spacing and low Reynolds numbers. The experimental data confirm previous findings from numerical simulations. These had suggested that for small insects, flying with bristled instead of membranous wings involved less change in energetic costs than for large insects. In sum, our findings highlight the aerodynamic changes associated with bristled wing designs and are thus significant for assessing the biological fitness and dispersal of flying insects.

Novel flight style and light wings boost flight performance of tiny beetles

Flight speed is positively correlated with body size in animals1. However, miniature featherwing beetles can fly at speeds and accelerations of insects three times their size2. Here we show that this performance results from a reduced wing mass and a previously unknown type of wing-motion cycle. Our experiment combines three-dimensional reconstructions of morphology and kinematics in one of the smallest insects, the beetle Paratuposa placentis (body length 395 μm). The flapping bristled wings follow a pronounced figure-of-eight loop that consists of subperpendicular up and down strokes followed by claps at stroke reversals above and below the body. The elytra act as inertial brakes that prevent excessive body oscillation. Computational analyses suggest functional decomposition of the wingbeat cycle into two power half strokes, which produce a large upward force, and two down-dragging recovery half strokes. In contrast to heavier membranous wings, the motion of bristled wings of the same size requires little inertial power. Muscle mechanical power requirements thus remain positive throughout the wingbeat cycle, making elastic energy storage obsolete. These adaptations help to explain how extremely small insects have preserved good aerial performance during miniaturization, one of the factors of their evolutionary success.

Functional morphology of Quetzalcoatlus Lawson 1975 (Pterodactyloidea: Azhdarchoidea)

ABSTRACT We reconstruct the proportions and possible motions of the skeleton of the giant azhdarchid pterosaur Quetzalcoatlus. The neck had substantial dorsoventral mobility, and the head and the neck could swing left and right through an arc of ca. 180°. In flight, it is most plausible that the hind limbs were drawn up bird-like, with the knee anterior to the acetabulum. In this position, an attachment of the wing membrane to the hind limb would have been useless. A straight-legged posterior extension of the hind limb, such as rotation of the hind limb into a fully ‘bat-like’ pose, was likely prevented by soft tissues of the hip joint. Given these difficulties, the traditional ‘broad-winged’ bat-like restoration is unrealistic. On the ground, Quetzalcoatlus, like other ornithodirans, had an erect stance and a parasagittal gait. Terrestrial locomotion was powered almost entirely by the hind limbs. The pace length would have been limited to the length of the glenoacetabular distance, except that Quetzalcoatlus (like other pterodactyloids) had a unique gait in which the forelimb was elevated out of the way of the hind limb from step to step. If the humerus were retracted 80° and adducted nearly to the body wall, the elbow and wrist may have been able to extend to effect a quadrupedal launch with assistance from the hind limbs, assuming sufficient long bone strength and sufficient extensor musculature at these forelimb joints. A bipedal launch using the hind limbs alone also appears plausible: despite the animal’s great size, the hind limb to torso length ratio is the greatest for all known pterosaurs.

On the genus Polypedilum, subgenus Collartomyia, with description of P. (Col.) baishanzuensis sp. nov. from Baishanzu Nature Reserve, China (Diptera, Chironomidae).

A new species of the genus Polypedilum Kieffer, 1912 is described from Baishanzu Nature Reserve, China, based on molecular and morphological data. Molecular phylogenetic analysis based on standard barcode sequences confirmed a new clade of Polypedilum (Collartomyia) species. The new species is easily distinguished from its congeners by a combination of the following morphological characters: membrane of wing with a large spot occupying 70% of the proximal area; tergite without dark brown band pigmentation; tarsi I–V dark brown; superior volsella with three outer lateral setae and six long setae along inner base; inferior volsella with setose tubercules. An updated key to adult males of the subgenus Collartomyia is also provided.

First record of Neurosystasis Satchell in Mexico, with the description of one new species (Diptera, Psychodidae), and the validation of Chuspilepia Omad, Mangudo & Gleiser as subgenus

Neurosystasis Satchell is newly recorded in Mexico by means of the description of a new species. Specimens captured in a tropical deciduous forest in southern Puebla, central Mexico, were examined and determined as a species new to science. The male and female are described based on morphological characteristics. Neurosystasis longistylis sp. nov. is similar in appearance to Neurosystasis saltenia (Omad, Mangudo & Gleiser, 2015), but is readily distinguished based on characters of the head, wing, and male genitalia. In both species, R2+3 is attached to vein R4, the wing membrane is infuscate with dark spots on vein apices, and lacks sensory organs near the apex of Sc, characters not present in other species of Neurosystasis, and for that reasons we proposed the recovery of Chuspilepia from its synonym and validate it as a subgenus of Neurosystasis to include both continental species.

Flight efficiency is a key to diverse wing morphologies in small insects.

Insect wings are hybrid structures that are typically composed of veins and solid membranes. In some of the smallest flying insects, however, the wing membrane is replaced by hair-like bristles attached to a solid root. Bristles and membranous wing surfaces coexist in small but not in large insect species. There is no satisfying explanation for this finding as aerodynamic force production is always smaller in bristled than solid wings. This computational study suggests that the diversity of wing structure in small insects results from aerodynamic efficiency rather than from the requirements to produce elevated forces for flight. The tested wings vary from fully membranous to sparsely bristled and were flapped around a wing root with lift- and drag-based wing kinematic patterns and at different Reynolds numbers (Re). The results show that the decrease in aerodynamic efficiency with decreasing surface solidity is significantly smaller at Re = 4 than Re = 57. A replacement of wing membrane by bristles thus causes less change in energetic costs for flight in small compared to large insects. As a consequence, small insects may fly with bristled and solid wing surfaces at similar efficacy, while larger insects must use membranous wings for an efficient production of flight forces. The above findings are significant for the biological fitness and dispersal of insects that fly at elevated energy expenditures.

Generative design of bioinspired wings based on deployable hindwings of Anomala Corpulenta Motschulsky

In view of the application prospect of the hindwing of Anomala Corpulenta Motschulsky in the field of foldable Micro Aerial Vehicles (MAVs), this paper investigated the morphology, macro/microstructure of the hindwing, and the nanomechanical properties of the wing veins and the wing membrane. It revealed the variation of nanohardness and elastic modulus between different veins and different positions of the same wing veins. This paper established a 3D coupling model of the hindwing based on the principle of coupling bionics. This paper presents a simulation analysis of the structural statics (uniform load distribution) and aerodynamics (under different attack angles, flight velocities, and flapping frequencies). Two 3D coupling models (HW-I and HW-II) of the hindwing were discussed the deformation and flight aerodynamic performance of Workbenches and Fluent. On that basis, the bionic wing was generatively designed, and a 3D bionic wing (BioW) model was established using the generative design method. Simulation analyses were performed through structural statics and aerodynamics. The results showed that the stress distribution was relatively uniform and that the overall displacement deformation was minimal for the BioW model. Moreover, the BioW model had better flight efficiency and aerodynamic performance.

Lipid composition of the stratum corneum in different regions of the body of Kuhl's pipistrelle from the Negev Desert, Israel

The most superficial epidermal layer in endotherms is the stratum corneum (SC), which is composed of dead corneocytes embedded in a lipid matrix with free fatty acids, cholesterol, ceramides, and cerebrosides; the lipid composition of the SC determines its permeability to water vapor. Lipids that are more polar, have longer hydrocarbon chains, and are less bulky are often packed in more ordered phase states to slow cutaneous evaporative water loss (CEWL); these lipids also resist transitions to more disordered phases at high ambient temperatures (Ta). In bats, wing and tail membranes (wing patagia and tail uropatagium, respectively) allow powered flight, but increase surface area, and hence CEWL, with implications for survival in arid environments. We captured Pipistrellus kuhlii from an arid habitat and measured the lipid composition of the SC of the plagiopatagium in the wing, the uropatagium, and the non-membranous region (NMR) of the body using thin layer chromatography and reversed phase high performance liquid chromatography coupled with atmospheric pressure photoionization mass spectrometry. The patagia contained more cholesterol and shorter-chained ceramides, and fewer cerebrosides than the NMR, indicating that the lipid phase transition temperature in the patagia is lower than in the NMR. Thus, at moderate Ta the lipids in the SC in all body regions will remain in an ordered phase state, allowing water conservation; but as Ta increases, the lipids in the SC of the patagia will more easily transition into a disordered phase, resulting in increased CEWL from the patagia facilitating efficient heat dissipation in hot environments.

Regulation of metamorphosis in neopteran insects is conserved in the paleopteran Cloeon dipterum (Ephemeroptera)

In the Paleozoic era, more than 400 Ma, a number of insect groups continued molting after forming functional wings. Today, however, flying insects stop molting after metamorphosis when they become fully winged. The only exception is the mayflies (Paleoptera, Ephemeroptera), which molt in the subimago, a flying stage between the nymph and the adult. However, the identity and homology of the subimago still is underexplored. Debate remains regarding whether this stage represents a modified nymph, an adult, or a pupa like that of butterflies. Another relevant question is why mayflies have the subimago stage despite the risk of molting fragile membranous wings. These questions have intrigued numerous authors, but nonetheless, clear answers have not yet been found. By combining morphological studies, hormonal treatments, and molecular analysis in the mayfly Cloeon dipterum, we found answers to these old questions. We observed that treatment with a juvenile hormone analog in the last nymphal instar stimulated the expression of the Kr-h1 gene and reduced that of E93, which suppress and trigger metamorphosis, respectively. The regulation of metamorphosis thus follows the MEKRE93 pathway, as in neopteran insects. Moreover, the treatment prevented the formation of the subimago. These findings suggest that the subimago must be considered an instar of the adult mayfly. We also observed that the forelegs dramatically grow between the last nymphal instar, the subimago, and the adult. This necessary growth spread over the last two stages could explain, at least in part, the adaptive sense of the subimago.

Bionic Adaptive Thin‐Membranes Sensory System Based on Microspring Effect for High‐Sensitive Airflow Perception and Noncontact Manipulation

AbstractRecently airflow sensors based on mechanical deformation mechanisms have drawn extensive attention due to their favorable flexibility and sensitivity. However, the fabrication of highly sensitive and self‐adaptive airflow sensors in a simple, controllable, and scalable method still remains a challenge. Herein, inspired by the wing membrane of a bat, a highly sensitive and adaptive graphene/single‐walled nanotubes‐Ecoflex membrane (GSEM) based airflow sensor mediated by the reversible microspring effect is developed. The fabricated GSEM is endowed with an ultralow airflow velocity detection limit (0.0176 m s−1), a fast response time (≈1.04 s), and recovery time (≈1.28 s). The GSEM‐based airflow sensor can be employed to realize noncontact manipulation. It is applied to a smart window system to realize the intelligent, open, and close behaviors via a threshold control. In addition, an array of airflow sensors is effectively designed to differentiate the magnitude and spatial distribution of the applied airflow stimulus. The GSEM‐based airflow sensor is further integrated into a wireless vehicle model system, which can sensitively capture the flow velocity information to realize a real‐time direction of motion manipulation. The microspring effect‐based airflow sensing system shows significant potentials in the fields of wearable electronics and noncontact intelligent manipulation.

A Rapid, in-Situ Minimally-Invasive Technique to Assess Infections with Pseudogymnoascus destructans in Bats

Emerging infectious diseases may become serious threats to wildlife, a prominent example being the white-nose disease (WND). In case of WND, the cold-loving fungus Pseudogymnoascus destructans colonizes bats during hibernation, invades the skin and has already lead to the death of millions of bats in North America. P. destructans most likely originated from Europe, where it also causes lesions but without associated mortalities. However, it is still unclear how European bats cope with the fungus. Hence, it is important to have tools that precisely characterise disease progression. Because hibernation is a physiological state during which bats are vulnerable to disturbance, in-situ assessments of the clinical status should be carried out minimal-invasively to avoid detrimental impacts on bats. However, currently available disease assessment methods require handling/touching bats and are therefore invasive: i) UV-light trans-illumination of wing membranes to detect lesions and ii) a qPCR-based quantification of fungal material from wing membrane swabs. Since P. destructans (‘Pd') becomes visible on all furless skin with distinct distribution patterns, we investigated the use of visible symptoms to assess levels of infections without handling/touching bats. We introduce a technique which we termed ‘Visual Pd-score’ (a visual classification scheme), which can be applied without disturbing the animals. To assess its reliability, we used P. destructans infected greater mouse-eared bats (Myotis myotis) to compare the novel method with the two existing golden-standard techniques. Our results show that infection levels obtained from all three techniques are correlated. Importantly, the information carried by the Visual Pd-score is most similar to a composite index combining the information from the qPCR-based and UV-light quantification methods. We conclude that the Visual Pd-score represents a promising index to better characterise disease severity as it is simultaneously representative for fungal colonization and wing damage. We discuss advantages and disadvantages of the applied techniques and conclude that the Visual Pd-score is particularly useful for routine hibernacula counts or large-scale P. destructans-surveillance. In combination with the lesion detection technique the new method is also applicable to immunological studies where both fungal colonization and associated damage have to be investigated, while qPCRs from swabs of all body parts are especially useful if it is necessary to detect cryptic infections, e.g. during the early hibernation period.

Male Chemical Signalling to Recruit Females in the Greater Short-Nosed Fruit Bat Cynopterus sphinx

Mate attraction via chemosignalling is common in group-living mammals. In the greater short-nosed fruit bats, Cynopterus sphinx, it remains unclear whether males use chemosignals to attract females. Here, we use field observations to describe patterns of male chemosignalling in this species, then use preference test in captivity to infer the function of chemosignals. We observed that males engage in chemosignalling through wing fanning after marking their leaf ‘tent' roosts with saliva. The male fanned each wing alternatively and vigorously and performed frequent tongue flicks to the wing membrane. Such behaviour is exhibited towards females that returned to the tent. Afterwards, the male embraced the female with both wings. Wing fanning and tent marking occurred more often during the mating season than the non-mating season. To infer the role of chemosignals in recruiting females, we performed two different choice tests. In the first test, we tested whether females preferred the tent containing cotton balls that were rubbed gently and repeatedly on the ventral side of the plagiopatagium of the male, versus a control tent without any conspecific odour. In the second test, we tested whether females preferred a tent that was marked by a male's saliva versus a control tent without such markings. The result of both tests indicated that females recognized the saliva and ‘scent’ from the wings of males, since females always preferred tents with male chemosignals over the controls. Our findings suggest that the recruitment of females and subsequent formation of a harem in the greater short-nosed fruit bats is influenced by male chemosignals.

<p><strong>A novel species of <em>Ischaemum </em>(Poaceae, Andropogoneae) from the northern Western Ghats, India, based on morphological and molecular data</strong></p>

Ischaemum amboliense (Poaceae, Andropogoneae), a new species of Muraina grass, is described and illustrated here. The new species is closely allied to I. travancorense but differs from it in having annual habit and erect posture, culm with sparsely hairy nodes, well-exerted racemes, lower glumes of sessile spikelets with 3–4 side nodules without ridges, upper glume of sessile spikelets with bicuspidate apex and margins with a membranous wing on one side of apical region and lower lemma of sessile spikelets winged on both sides towards the apex. A strict consensus tree obtained from the Maximum Likelihood and Bayesian analyses of trnLC–trnLD and ETS datasets supported the novelty of the species. Here, we provide a detailed morphological description, molecular phylogenetic analysis, distribution map, and photo-plates of the novel and allied species.

Developmental, cellular and biochemical basis of transparency in clearwing butterflies.

ABSTRACTThe wings of butterflies and moths (Lepidoptera) are typically covered with thousands of flat, overlapping scales that endow the wings with colorful patterns. Yet, numerous species of Lepidoptera have evolved highly transparent wings, which often possess scales of altered morphology and reduced size, and the presence of membrane surface nanostructures that dramatically reduce reflection. Optical properties and anti-reflective nanostructures have been characterized for several ‘clearwing’ Lepidoptera, but the developmental processes underlying wing transparency are unknown. Here, we applied confocal and electron microscopy to create a developmental time series in the glasswing butterfly, Greta oto, comparing transparent and non-transparent wing regions. We found that during early wing development, scale precursor cell density was reduced in transparent regions, and cytoskeletal organization during scale growth differed between thin, bristle-like scale morphologies within transparent regions and flat, round scale morphologies within opaque regions. We also show that nanostructures on the wing membrane surface are composed of two layers: a lower layer of regularly arranged nipple-like nanostructures, and an upper layer of irregularly arranged wax-based nanopillars composed predominantly of long-chain n-alkanes. By chemically removing wax-based nanopillars, along with optical spectroscopy and analytical simulations, we demonstrate their role in generating anti-reflective properties. These findings provide insight into morphogenesis and composition of naturally organized microstructures and nanostructures, and may provide bioinspiration for new anti-reflective materials.

Check-Valve Design in Enhancing Aerodynamic Performance of Flapping Wings

A flapping wing micro air vehicle (FWMAV) demands high lift and thrust generation for a desired payload. In view of this, the present work focuses on a novel way of enhancing the lift characteristics through integrating check-valves in the flapping wing membrane. Modal analysis and static analysis are performed to determine the natural frequency and deformation of the check-valve. Based on the inference, the check-valve opens and closes during the upstroke flapping and downstroke flapping, respectively. Wind tunnel experiments were conducted by considering the two cases of wing design, i.e., with and without a check-valve for various driving voltages, wind speeds and different inclined angles. A 20 cm-wingspan polyethylene terephthalate (PET) membrane wing with two check-valves, composed of central disc-cap with radius of 7.43 mm, supported by three S-beams, actuated by Evans mechanism to have 90° stroke angle, is considered for the 10 gf (gram force) FWMAV study. The aerodynamic performances, such as lift and net thrust for these two cases, are evaluated. The experimental result demonstrates that an average lift of 17 gf is generated for the case where check-valves are attached on the wing membrane to operate at 3.7 V input voltage, 30° inclined angle and 1.5 m/s wind speed. It is inferred that sufficient aerodynamic benefit with 68% of higher lift is attained for the wing membrane incorporated with check-valve.

Unexpected genomic, biosynthetic and species diversity of Streptomyces bacteria from bats in Arizona and New Mexico, USA

BackgroundAntibiotic-producing Streptomyces bacteria are ubiquitous in nature, yet most studies of its diversity have focused on free-living strains inhabiting diverse soil environments and those in symbiotic relationship with invertebrates.ResultsWe studied the draft genomes of 73 Streptomyces isolates sampled from the skin (wing and tail membranes) and fur surfaces of bats collected in Arizona and New Mexico. We uncovered large genomic variation and biosynthetic potential, even among closely related strains. The isolates, which were initially identified as three distinct species based on sequence variation in the 16S rRNA locus, could be distinguished as 41 different species based on genome-wide average nucleotide identity. Of the 32 biosynthetic gene cluster (BGC) classes detected, non-ribosomal peptide synthetases, siderophores, and terpenes were present in all genomes. On average, Streptomyces genomes carried 14 distinct classes of BGCs (range = 9–20). Results also revealed large inter- and intra-species variation in gene content (single nucleotide polymorphisms, accessory genes and singletons) and BGCs, further contributing to the overall genetic diversity present in bat-associated Streptomyces. Finally, we show that genome-wide recombination has partly contributed to the large genomic variation among strains of the same species.ConclusionsOur study provides an initial genomic assessment of bat-associated Streptomyces that will be critical to prioritizing those strains with the greatest ability to produce novel antibiotics. It also highlights the need to recognize within-species variation as an important factor in genetic manipulation studies, diversity estimates and drug discovery efforts in Streptomyces.

Muscle fibre distribution in forelimb, hindlimb and trunk muscles in three bat species: The little Japanese horseshoe, greater horseshoe and Egyptian fruit.

This study characterised muscle fibres in trunk, forelimb and hindlimb muscles of three bat species: little Japanese horseshoe (Rhinolophus cornutus), greater horseshoe (Rhinolophus ferrumequinum) and Egyptian fruit (Rousettus aegyptiacus). Twenty-seven muscles from trunk, forelimb and hindlimb were dissected, weighed and analysed by immunohistochemistry and sodium didecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and determined their cross-sectional areas (CSA). Results showed that Type IIa and Type IIa/x made the highest proportion of total muscle mass. Moderate proportion was formed by Type IIb. Type I and IIx appeared at very low levels in all bats. Type IIb was the only fibre type detected in patagial muscles in wing membrane of greater horseshoe while other fibre types were not observed. Type I muscle fibres were very few and appeared infrequently in fifteen muscles of Egyptian fruit and in only one muscle in each, greater horseshoe and little Japanese horseshoe. Type IIx was also detected in three muscles in greater horseshoe and only one muscle in Egyptian fruit but none in little Japanese horseshoe. The highest average CSA μm2 was detected in Type IIb and values were 734.2μm2 for LHB; 1537.9μm2 for GHB and 1,720.9μm2 for EFB. Lowest and undetermined values were observed for Type I and IIx. These data demonstrate that Type IIa, IIa/x and IIb form significant proportion of adult bat muscle mass and Type IIb is the largest fibre type. The distribution pattern is suggestive of specialised functions of the fibres in relation to orientation and speed of bats during flight.