Plecotus Auritus Research Articles

Fidelity of Bats to Forest Sites Revealed From Mist-Netting Recaptures

Abstract Although site fidelity to permanent roost structures by bats is generally known, long-term fidelity to areas such as foraging or drinking sites is unknown. Furthermore, mist-net recaptures of bats over multiple years are rarely reported. Extensive mist-net surveys were conducted over the course of 8 y in the Ouachita National Forest of central Arkansas, United States to investigate long-term site fidelity and recapture rates of individually marked forest bats. Among eight species that were captured, five species were recaptured over spans ≥1 y, including eastern red bats Lasiurus borealis, Seminole bats L. seminolus, evening bats Nycticeius humeralis, tri-colored bats Lasiurus borealis, and northern long-eared bats Myotis septentrionalis. Some individuals were recaptured multiple times over multiple years, and the maximum span over which an individual was recaptured was 1 y for Seminole bats, 2 y for tri-colored bats, 3 y for evening bats, 4 y for eastern red bats, and 5 y for northern long-eared bats. These results indicate long-term site fidelity by multiple bat species to particular forest sites, primarily pools along small intermittent streams. Proximity to these sites should be considered when conducting management activities.

Alphacoronaviruses in New World bats: prevalence, persistence, phylogeny, and potential for interaction with humans.

Bats are reservoirs for many different coronaviruses (CoVs) as well as many other important zoonotic viruses. We sampled feces and/or anal swabs of 1,044 insectivorous bats of 2 families and 17 species from 21 different locations within Colorado from 2007 to 2009. We detected alphacoronavirus RNA in bats of 4 species: big brown bats (Eptesicus fuscus), 10% prevalence; long-legged bats (Myotis volans), 8% prevalence; little brown bats (Myotis lucifugus), 3% prevalence; and western long-eared bats (Myotis evotis), 2% prevalence. Overall, juvenile bats were twice as likely to be positive for CoV RNA as adult bats. At two of the rural sampling sites, CoV RNAs were detected in big brown and long-legged bats during the three sequential summers of this study. CoV RNA was detected in big brown bats in all five of the urban maternity roosts sampled throughout each of the periods tested. Individually tagged big brown bats that were positive for CoV RNA and later sampled again all became CoV RNA negative. Nucleotide sequences in the RdRp gene fell into 3 main clusters, all distinct from those of Old World bats. Similar nucleotide sequences were found in amplicons from gene 1b and the spike gene in both a big-brown and a long-legged bat, indicating that a CoV may be capable of infecting bats of different genera. These data suggest that ongoing evolution of CoVs in bats creates the possibility of a continued threat for emergence into hosts of other species. Alphacoronavirus RNA was detected at a high prevalence in big brown bats in roosts in close proximity to human habitations (10%) and known to have direct contact with people (19%), suggesting that significant potential opportunities exist for cross-species transmission of these viruses. Further CoV surveillance studies in bats throughout the Americas are warranted.

Increasing bat abundance in a major winter roost in central Poland over 30 years

Abstract A bat census in the years 1981–2010 (repeated twice during each hibernation period in January and March) showed upward trends in many populations of bats hibernating in the Szachownica Cave (central Poland). Total numbers of the bat assemblage, which consisted of 11 species, increased within the study period from 178 to 1477 individuals in the first decade to 835–2902 in the past decade of the study, with the highest rates of increase noted in Barbastella barbastellus, Plecotus auritus and Myotis nattereri. Myotis myotis and Myotis daubentonii showed only slight upward trends. In the years 2009–2010, Myotis bechsteinii occurred in markedly higher numbers (up to 24 individuals) as compared to previous years.

A Potential Role for Bat Tail Membranes in Flight Control

Wind tunnel tests conducted on a model based on the long-eared bat Plecotus auritus indicated that the positioning of the tail membrane (uropatagium) can significantly influence flight control. Adjusting tail position by increasing the angle of the legs ventrally relative to the body has a two-fold effect; increasing leg-induced wing camber (i.e., locally increased camber of the inner wing surface) and increasing the angle of attack of the tail membrane. We also used our model to examine the effects of flying with and without a tail membrane. For the bat model with a tail membrane increasing leg angle increased the lift, drag and pitching moment (nose-down) produced. However, removing the tail membrane significantly reduced the change in pitching moment with increasing leg angle, but it had no significant effect on the level of lift produced. The drag on the model also significantly increased with the removal of the tail membrane. The tail membrane, therefore, is potentially important for controlling the level of pitching moment produced by bats and an aid to flight control, specifically improving agility and manoeuvrability. Although the tail of bats is different from that of birds, in that it is only divided from the wings by the legs, it nonetheless, may, in addition to its prey capturing function, fulfil a similar role in aiding flight control.

Torpor and activity in a free-ranging tropical bat: implications for the distribution and conservation of mammals?

Bats are most diverse in the tropics, but there are no quantitative data on torpor use for energy conservation by any tropical bat in the wild. We examined the thermal biology, activity patterns and torpor use of two tree-roosting long-eared bats (Nyctophilus geoffroyi, 7.8 g) in tropical northern Australia in winter using temperature telemetry. Bats commenced activity about 20 min after sunset, ended activity about 2.5 h before sunrise and entered torpor everyday in the early morning even when minimum ambient temperatures (T (a)) were as high as 23°C. On average, bats remained torpid for almost 5 h, mean minimum skin temperature (T (skin)) measured was 22.8 ± 0.1°C and daily T (skin) minima were correlated with T(a). Our study shows that even in the tropics, torpor is frequently employed by bats, suggesting that worldwide most bat species are heterothermic and use torpor for energy conservation. We propose that the ability of employing torpor and the resulting highly plastic energy requirements may partially explain why these small insectivorous bats can inhabit almost the entire Australian continent despite vastly different climatic and likely trophic conditions. Reduced energy requirements also may permit survival in degraded or modified habitats, reduce the need for foraging and reduce exposure to predators. Thus, the ability to employ torpor may be one important reason for why most Australian bats and other heterothermic mammals have not gone extinct whereas many obligatory homeothermic mammals that cannot employ torpor and have high energy and foraging requirements have suffered high rates of extinctions.

Trophic niche partitioning of cryptic species of long-eared bats in Switzerland: implications for conservation

Dietary niche partitioning is postulated to play a major role for the stable coexistence of species within a community, particularly among cryptic species. Molecular markers have recently revealed the existence of a new cryptic species of long-eared bat, Plecotus macrobullaris, in the European Alps. We studied trophic niches as well as seasonal and regional variations of diet in eight colonies of the three Plecotus species occurring in Switzerland. Faeces were collected monthly from individuals returning to roost after foraging. Twenty-one arthropod categories were recognized from the faeces. All three species fed predominantly on Lepidoptera, which made up 41%, 87% and 88% (means across colonies) of the diet composition of P. auritus, P. macrobullaris and P. austriacus, respectively. The occurrence of numerous fragments of both diurnal and flightless insects in the diet of P. auritus (but rarely in the diet of the other two species) indicates that this species mostly gleans prey from substrates. P. austriacus and P. macrobullaris are more typical aerial feeders. The latter two species have narrow trophic niches, whilst P. auritus has a much broader diet. Comparison of intraspecific and interspecific niche overlaps in P. auritus and P. macrobullaris in sympatry suggests dietary niche partitioning between these two species. In contrast, the high similarity of the trophic niches of P. austriacus and P. macrobullaris, associated with a typical parapatric distribution, indicates competitive exclusion. The best conservation measures are preservation and restoration of habitats offering a high abundance of moths, the major prey of the three Plecotus species.

Fauna and structure of bat (Chiroptera) assemblage of the National Park ‘Smolensk Lakeland’, western Russia

The data presented in this paper is a result of inventory of bat fauna and structure of assemblage in the National Park ‘Smolensk Lakeland’, Smolensk region, Russia. A total of 318 bats of eight species (Myotis brandtii, M. mystacinus, M. daubentonii, Nyctalus noctula, N. leisleri, Pipistrellus nathusii, Vespertilio murinus and Plecotus auritus) were captured in mist nets in June and July 2010. Six species were new for the territory of the National Park. N. noctula was a dominant, P. nathusii and V. murinus were subdominant species, other five species were rare. Among adult individuals, females were predominant. Sex ratio among subadults of dominant and subdominant bat species was equal. Six species were breeding within the territory. A comparison of our results with the data from regions adjacent to Smolensk (Bryansk, Tver, Moscow, Vitebsk) is discussed.

Emergence and flight routes of the lesser horseshoe bats Rhinolophus hipposideros (Bechstein, 1800) from a church at Ljubljansko barje, central Slovenia

The flight routes from roosts to feeding habitats are important for efficient conservation of bats, but in Slovenia they are poorly known. Emergence and flight routes of the lesser horseshoe bats Rhinolophus hipposideros from the Church of Sveti Duh at Vnanje Gorice, Ljubljansko barje, were monitored on ten different days in August and September 2009. In the beginning of August, 72 lesser horseshoe bats were counted in the attic; the number decreased to 29 in the beginning of September. Individuals of three other bat species were also found in the attic and belfry: the greater mouse eared bats Myotis myotis, serotine bats Eptesicus serotinus and a group of alpine long-eared bats Plecotus macrobullaris. The lesser horseshoe bats emerged only from a single opening in the attic. The first bat flew out on average 16 minutes after the sunset, while the first bat amongst those that did not return to the roost left on average 20 minutes after sunset. The lesser horseshoe bats flew few metres above the ground into the nearby forest Gulč on the northwestern side of the church. We observed flying bats at nine locations in this forest and at three locations on the forest edge, where they probably foraged. Bats flew along a lit road next to houses, close to a major road they had to cross, and next to a railway southwest from the church. The spatial and temporal distribution of observations indicated the flight towards the mixed forest Plešivica, where a lesser horseshoe bat was observed app. 1.7 km bee-line distance SW from the church at Vnanje Gorice. Considering that bats generally follow linear elements in the landscape, and on the basis of our observations at 21 locations and flight behaviour we envisaged the most likely course of their flight route. These data are important for efficient conservation of the lesser horseshoe bats roosting at Vnanje Gorice and maintenance of important landscape elements in the surrounding landscape.

Bats hibernating in underground shelters of Małe Pieniny mountains (the Carpathian Mountains, Southern Poland)

Bats hibernating in underground shelters of Małe Pieniny mountains (the Carpathian Mountains, Southern Poland) Six bat species were observed during winter censuses in years 2005-2009: Lesser horseshoe bat, Mouse-eared bat, Daubenton's bat, Whiskered/Brandt's bat, Northern bat and Brown long-eared bat. Rhinolophus hipposideros was most numerous (67% of all bats recorded). Largest hibernaculum on Polish side of range was mine Bania w Jarmucie, with maximum 29 bats during a single control, through the years of research number of species and individuals was increasing. Rarely seen in Outer Carpathians Eptesicus nilssonii winter roost was found in Homole Ravine Reserve.

Foraging Behavior of a Desert Dwelling Arthropod-Gleaning Bat (Otonycteris hemprichii) During Pregnancy and Nursing

We studied the role of behavioral activities used by desert-dwelling, arthropod gleaning Hemprich's long-eared bat (Otonycteris hemprichii), hypothesizing that there is a trade off between their own and their offspring's food needs. Specifically, we tested the following predictions: 1) females will bring forward their emergence time from their roosts and increase foraging bout length progressively from the first through the second trimesters of pregnancy, and during nursing as their pups grow; but, that 2) during the last trimester of pregnancy, namely, in the final stages of foetus development, females will emerge later and there will be a reduction in foraging effort (time); and that 3) females will spend more time foraging during nursing than during pregnancy. We found that the bats emerged from their roosts to forage earlier during the first trimester, but not during the last two trimesters of pregnancy, and that they did not change their emergence time as nursing progressed. Bats that emerged later at night during pregnancy spent more time foraging, and, except for the third trimester, the length of the first daily foraging bout increased as both pregnancy and nursing progressed. Total daily foraging time increased as pregnancy and nursing progressed. Generally, these results support our hypothesis; through adjustment of their foraging behavior as embryos and pups develop, breeding female Hemprich's long-eared bats contend with the potentially conflicting food requirements of their offspring and their own needs.

Hemprich's long-eared bat (Otonycteris hemprichii) as a predator of scorpions: whispering echolocation, passive gleaning and prey selection.

Over 70% of the droppings of the gleaning bat Otonycteris hemprichii can contain scorpion fragments. Yet, some scorpions found in its desert habitat possess venom of the highest known toxicity, rendering them a very dangerous prey. In this study, we describe how O. hemprichii catches and handles scorpions, quantify its flight and echolocation behaviour in the field, investigate what sensory modality it uses to detect scorpions, and test whether it selects scorpions according to their size or toxicity. We confirmed that O. hemprichi is a whispering bat (approx. 80 dB peSPL) with short, multi-harmonic calls. In a flight room we also confirmed that O. hemprichii detects scorpions by their walking noises. Amplitudes of such noises were measured and they reach the flying bat at or below the level of echoes of the loess substrate. Bats dropped straight onto moving scorpions and were stung frequently even straight in their face. Stings did not change the bats' behaviour and caused no signs of poisoning. Scorpions were eaten including poison gland and stinger. Bats showed no preference neither for any of the scorpion species nor their size suggesting they are generalist predators with regard to scorpions.

Ectoparasite associations of bats from Urals (Russia)

New data on bat ectoparasites from the Middle and Northern Urals are re- ported. Twenty species, belonging to 8 families of insects and mites were found on six bat species: Myotis dasycneme, M. daubentonii, M. brandtii, Eptesicus nilsonii, Vespertilio murinus, Plecotus auritus. All ectoparasite species are usual for Northern Eurasia.

Roost site selection by southern forest bat Vespadelus regulus and Gould's long-eared bat Nyctophilus gouldi in logged jarrah forests; south-western Australia

Information on roosting requirements and responses to forest management is integral to effectively conserve and manage bat populations. Tree hollows are especially important for roosting bats given the long time taken for hollows to form. We used radiotelemetry to compare roost site selection in two species, Vespadelus regulus and Nyctophilus gouldi, in logged jarrah forests of south-western Australia. We compared characteristics of roost trees and forest structure around roost trees (n=48) with randomly located plots at a local roost tree level (n=90) in February and March 2009. For landscape features, we compared roost trees with randomly selected trees in the broader landscape that had cavities or exfoliating bark (n=204). V. regulus roosted solely in hollows that were located predominantly in contemporarily unlogged buffers and mature forest while N. gouldi used a broader range of roost types, located in contemporarily unlogged buffers and mature forest and in retained habitat trees in gap release and shelterwood creation silvicultural treatments. In contrast with N. gouldi, which selected hollows or crevices under bark near the ground and close to vegetation, V. regulus used hollows that were high above ground and had little surrounding vegetation. Both species preferred large trees, in intermediate or advanced stages of decay and crown senescence. Bats changed roosts frequently, with short distances between subsequent roosts, suggesting a degree of spatial fidelity. Contemporarily unlogged buffers and mature forest contained higher densities of trees with hollows than gap release and shelterwood creation areas, potentially providing more alternate bat roosts. Our results demonstrate the importance of mature forest and unlogged buffers as bat roost sites in logged jarrah forests of south-western Australia, but the area of old forest required by these and co-occurring bat species remains to be determined.

Numerical analysis of biosonar beamforming mechanisms and strategies in bats

Beamforming is critical to the function of most sonar systems. The conspicuous noseleaf and pinna shapes in bats suggest that beamforming mechanisms based on diffraction of the outgoing and incoming ultrasonic waves play a major role in bat biosonar. Numerical methods can be used to investigate the relationships between baffle geometry, acoustic mechanisms, and resulting beampatterns. Key advantages of numerical approaches are: efficient, high-resolution estimation of beampatterns, spatially dense predictions of near-field amplitudes, and the malleability of the underlying shape representations. A numerical approach that combines near-field predictions based on a finite-element formulation for harmonic solutions to the Helmholtz equation with a free-field projection based on the Kirchhoff integral to obtain estimates of the far-field beampattern is reviewed. This method has been used to predict physical beamforming mechanisms such as frequency-dependent beamforming with half-open resonance cavities in the noseleaf of horseshoe bats and beam narrowing through extension of the pinna aperture with skin folds in false vampire bats. The fine structure of biosonar beampatterns is discussed for the case of the Chinese noctule and methods for assessing the spatial information conveyed by beampatterns are demonstrated for the brown long-eared bat.

Similar is not the same: Social calls of conspecifics are more effective in attracting wild bats to day roosts than those of other bat species

Many bat species regularly need to find new day roosts as they require numerous shelters each breeding season. It has been shown that bats exchange information about roosts among colony members, and use echolocation and social calls of conspecifics in order to find roosts. However, it is unclear if wild bats discriminate between social calls of conspecifics and other bat species while searching for roosts. Furthermore, the extent that bats are attracted to potential roosts by each of these two call types is unknown. We present a field experiment showing that social calls of conspecifics and other bat species both attract bats to roosts. During two summers, we played back social calls of Bechstein’s bats (Myotis bechsteinii) and Natterer’s bats (Myotis nattereri) from different bat boxes that can serve as roosts for these species. All experimental bat boxes were monitored with infrared video to identify the approaching bat species. Three species (M. bechsteinii, M. nattereri, and Plecotus auritus) approached the boxes significantly more often during nights when bat calls were played compared to nights without playbacks. Bechstein’s bats and Natterer’s bats were both more attracted to social calls of conspecifics than of the other species, whereas P. auritus did not discriminate between calls of either Myotis species. Only Bechstein’s bats entered experimental boxes and only at times when calls from conspecifics were played. Our findings show that wild bats discriminate between social calls of conspecifics and other bat species although they respond to both call types when searching for new roosts.

Multiple morphological characters needed for field identification of cryptic long‐eared bat species around the Swiss Alps

The identification of cryptic species may significantly change our view about their distribution, abundance, ecology and therefore conservation status. In the European Alps, molecular studies have revealed the existence of three sibling species of plecotine bats Plecotus auritus, Plecotus austriacus and, very recently, Plecotus macrobullaris. Knowledge of the ecological niche partitioning of cryptic species is a requisite to develop sound conservation policies. Yet, this requests the development of unambiguous identification methods easily applicable in the field. This study investigates the reliability of several morphological methods used for species recognition and proposes a new identification key for field workers. We captured 214 Plecotus bats from 29 sites in four bioregions within Switzerland, collected biopsy punches for genetic analysis, described and measured external morphological characters. All three species occurred as mono-specific colonies, except at one site where P. auritus and P. macrobullaris shared the same church attic. Qualitative traits alone did not allow a reliable separation of the three species. A series of multivariate analyses conducted on external linear measurements resulted in a discriminant function enabling correct species classification with a 97.5% probability. Compared with genetic analysis, our multivariate morphological method represents a valuable, rapid and cost-effective alternative.

Histomorphology of the Penis Bone (Baculum) in the Gray Long‐Eared Bat Plecotus austriacus (Chiroptera, Vespertilionidae)

For the first time, the histomorphology of the penis bone of a bat (Plecotus austriacus) was examined in detail. From Plecotus austriacus, 14 whole penes and 11 isolated bacula were studied and compared to bacula of Plecotus auritus and Plecotus macrobullaris. The baculum was located on specimen microradiographs and in micro-CT images in the tip of the penis. Using serial semithin sections and surface-stained, undecalcified ground sections, the types of bone and other tissues constituting the baculum were examined by light microscopy. 3D reconstructions were generated from the serial semithin sections and from micro-CT images. The shaft and the proximal branches of the Y-shaped baculum form a tubular bone around a medullary cavity. Since the small diameter of this channel and the main lamellar bone around it resemble a Haversian canal, the baculum is equivalent to a single-osteon bone. Several oblique nutrient canals enter this medullary cavity in the shaft and branches. All ends of the baculum consist predominantly of woven bone. The collagen fiber bundles of the tunica albuginea of both corpora cavernosa insert via fibrocartilage into the woven bone of the branches. Thus, the microscopic structures support the hypothesis that the baculum functions as a stiffening element in the erect penis. In this study, several microscopic imaging techniques were evaluated for displaying the microscopic structures of the baculum. Specimen microradiography, but especially micro-CT proved to be suitable nondestructive methods for accurate and reproducible demonstration and comparison of the three-dimensional structures of the baculum in different bat species.

Bat casualties on a road crossing a mosaic landscape

A year-round study was conducted on a 16.6-km road section crossing Kampinos National Park near Warsaw (central Poland). We found 61 road-killed bats belonging to seven species. The most abundant were: Nyctalus noctula, Plecotus auritus, and Barbastella barbastellus. Bats were found between the middle of April and the end of October with peaks in July/August and October. The density of bat casualties differed slightly in various habitats surrounding the road—lower values than expected were found only for windbreaks and bushes. The prediction that low-flying species are killed more frequently was not confirmed—the most abundant N. noctula usually flies at heights over 10 m above the ground. N. noctula, Myotis nattereri, and Pipistrellus nathusii were killed more frequently while Eptesicus serotinus less frequently than could be expected from the frequency with which they were captured in mist-nets on forest lanes.

Use of Temperature-Sensitive Transmitters to Monitor the Temperature Profiles of Hibernating Bats Affected with White-Nose Syndrome

In temperate ecosystems, hibernation allows bats to survive long periods of limited prey and water availability during colder months. Despite the extended amount of time some bats spend in hibernation, researchers have only recently been able to study the hibernation ecology of bats under natural conditions. With the emergence of white-nose syndrome (WNS), a mysterious disease presently killing large numbers of bats during the hibernation period in the northeastern United States, expanding our knowledge of hibernation ecology and natural history has become more crucial. To collect such data, we used temperature-sensitive radio transmitters and data loggers to monitor the skin temperatures (Tsk) of 6 bats (5 Myotis lucifugus [Little Brown Bat], and 1 Myotis septentrionalis [Northern Long-eared Bat]) hibernating in Mount Aeolus Cave, VT in late winter 2008. We recorded Tsk every 14 minutes for the life of the transmitters. We were able to monitor Tsk from near ambient temperatures to above 30 °C Arousals occurred immediately before the signals were lost and at a time of increased numbers of bats observed on the landscape, thereby suggesting the emergence (and subsequent death) of bats. Our observations provide first data on the hibernating ecology of WNS-affected bats under natural conditions.

LATEGLACIAL BATS FROM THE “M” LAYERS OF THE ARENE CANDIDE CAVE (LIGURIA, ITALY)

The Arene Candide Cave (Finale Ligure, Northern Italy) is considered one of the most important prehistoric site in Italy. The archaeological excavations conducted by the “Istituto Italiano di Paleontologia Umana” of Rome revealed 3 different horizons: an upper horizon with Holocene human presence dated from the Neolithic to the Byzantine period, and two underlying Pleistocene horizons with Gravettian and Epigravettian lithic artefacts. The stratigraphical sequence of the upper Palaeolithic is divided in two groups of strata separated by a depositional gap: the “P” complex, divided in 13 layers, dated from 25,620 to 18,560 years BP, and the 5 “M” layers dated between 11,750 and 9,980 years BP (14C non-calibrated dating). In this paper the fossil bone remains of bats from “M” layers are described. Fifteen taxa, divided into 3 families and 6 genera have been identified: Rhinolophus ferrumequinum , R. mehelyi , R. euryale , R. hipposideros , Myotis myotis , M. blythii , M. capaccinii , M. emarginatus , M. mystacinus s.l. , Myotis sp. (small sized), Plecotus auritus s.l ., Nyctalus lasiopterus , N. noctula , Barbastella barbastellus and Miniopterus schreibersii . Comments for each of these taxa on current ecological and geographical distributions are presented, together with some osteometric measures and recent data referred to Late Pleistocene fossils bats in Italy. Finally, the value of this bat tanathocoenoses as a microclimatic, environmental, and human activity indicators is discussed. SHORT NOTE