Mouse-eared Bat Myotis Research Articles

Cannibalism in maternity colonies of the greater mouse-eared bat Myotis myotis

No abstract available

Cave-dwelling bats do not avoid TMT and 2-PT – components of predator odour that induce fear in other small mammals

Recognition and avoidance of predators is fundamental for the survival of prey animals. Here we conducted the first study assessing chemosensory predator recognition in cave-dwelling bats. We used a Y-maze approach to test the reaction of greater mouse-eared bats (Myotis myotis) to two synthetically derived components of predator odour (2,4,5-trimethyl-3-thiazoline, TMT, a component of fox faeces scent; and 2-propylthietane, 2-PT, a component of mustelid scent) and to the natural scent of the least weasel (Mustela nivalis). It is well documented that rodents and several other small mammals show strong and at least partly innate fear reactions when confronted with these odorants. By contrast, the bats did not show any avoidance or fear reaction, despite the fact that relatively high odorant concentrations were presented. Furthermore, they did not react differently towards predator scent and towards acrid but otherwise neutral odours (basil or goat). The number of entries into in the Y-maze arm with the odour source and the time spent in this arm as well as the bats' overall exploratory activity and several other behavioural variables were not affected by the odour treatments. Generally, the sense of smell is well developed in bats and plays an important role in bat behavioural ecology. It is thus somewhat surprising that the bats did not show any avoidance reaction to predator scent, even though direct contact with a mustelid or fox would result in death. We discuss ecological explanations that might have prevented bats from evolving olfactory predatory recognition and avoidance.

Mitochondrial DNA Confirms Low Genetic Variation of the Greater Mouse-Eared Bats,Myotis myotis, in Central Europe

Recent data shows that range expansion of the greater mouse-eared bat Myotis myotis (Borkhausen, 1797) to Central Europe occurred mainly from the Iberian glacial refugium and in a lesser extent from South-eastern Europe. Here we present sequences of the mitochondrial control region obtained from 16 localities in the Czech Republic, Slovakia, and NW Romania. From the 97 sequences, 87 were identical with the haplotype H1, the most frequent one of haplogroup A occurring throughout Western Europe, and nine sequences (eight haplotypes) differed from H1 only by one substitution. This confirms decrease of genetic variability from south to north and colonisation of Central Europe from the Iberian Peninsula. However, we found a new haplotype, which is closely related to sequences from haplogroup D so far described in the nominative form of this species only from Greece and Bulgaria, which suggests two possible scenarios. First, colonization route from the Balkan refugium existed in this species as well, which is supported also by recently published analyses of historical DNA. Second, the Balkan haplotype entered Central Europe via interspecific hybridisation with M. blythii, a species, in which the haplogroup D is the most frequent in Europe and which is known to have colonised Europe from south-east.

Phenotypic plasticity in the greater mouse-eared bat in extremely different roost conditions

Bats use various roost types with a wide spectrum of ecological features. The greater mouse-eared bat Myotis myotis (Borkhausen, 1797), creates nurseries in attics and caves in Central Europe. The stable low temperature and high humidity cave microclimate contrasts that of attics, which may alter species adaptations and life strategies. We analysed population characteristics (composition, body condition, parasite load, and immune response) and genetic relatedness of two proximal M. myotis populations. Age, sexual and parasite species composition were similar between the cave and attic sites. However, a significantly higher parasite load and body condition was detected in the post-partum females and juveniles of the cave colony (n = 263 bats from the cave, 231 from the attic), with the cave colony females having a significantly stronger immune response (n = 2 caves and 2 attics, 20 females per site). There was no evidence for genetic divergence between cave and attic populations (n = 3 caves and 3 attics, 24 females per site), indicating that different population characteristics are not genetically based and that M. myotis is an example of a species with rather unique phenotypic plasticity.

A nocturnal mammal, the greater mouse-eared bat, calibrates a magnetic compass by the sun

Recent evidence suggests that bats can detect the geomagnetic field, but the way in which this is used by them for navigation to a home roost remains unresolved. The geomagnetic field may be used by animals both to indicate direction and to locate position. In birds, directional information appears to be derived from an interaction of the magnetic field with either the sun or the stars, with some evidence suggesting that sunset/sunrise provides the primary directional reference by which a magnetic compass is calibrated daily. We demonstrate that homing greater mouse-eared bats (Myotis myotis) calibrate a magnetic compass with sunset cues by testing their homing response after exposure to an altered magnetic field at and after sunset. Magnetic manipulation at sunset resulted in a counterclockwise shift in orientation compared with controls, consistent with sunset calibration of the magnetic field, whereas magnetic manipulation after sunset resulted in no change in orientation. Unlike in birds, however, the pattern of polarization was not necessary for the calibration. For animals that occupy ecological niches where the sunset is rarely observed, this is a surprising finding. Yet it may indicate the primacy of the sun as an absolute geographical reference not only for birds but also within other vertebrate taxa.

YersiniaSpecies Isolated from Bats, Germany

<i>Yersinia</i>Species Isolated from Bats, Germany

Habitat Selection and Activity Patterns in the Greater Mouse-Eared Bat Myotis myotis

The habitat preferences and activity of greater mouse-eared bats were investigated by means of radio-telemetry in two regions in Upper Franconia (Bavaria, Germany) that are characterized by a mosaic of deciduous forests, coniferous forests and woodless areas. In one case bats roosted in a maternity colony from which they visited foraging habitats up to 10.8 km away; in the second, the bats started in a cave which served as a night roost. These bats foraged around the cave up to 2.5 km away. Mean size of foraging areas was 13.1 ± 4.6 ha. Most of the bats used several foraging areas per night (mean 5.1, range 1–10). Hunting time per foraging site ranged from 5 to 224 (median 25) minutes. Foraging habitats in some individuals remained constant over two consecutive years. The bats hunted almost exclusively in woodland (98% of the hunting time) with a significant preference for deciduous forests as opposed to coniferous forests. The preference for deciduous forests as foraging habitats is likely to be caused b...

The Voice of Bats: How Greater Mouse-eared Bats Recognize Individuals Based on Their Echolocation Calls

Echolocating bats use the echoes from their echolocation calls to perceive their surroundings. The ability to use these continuously emitted calls, whose main function is not communication, for recognition of individual conspecifics might facilitate many of the social behaviours observed in bats. Several studies of individual-specific information in echolocation calls found some evidence for its existence but did not quantify or explain it. We used a direct paradigm to show that greater mouse-eared bats (Myotis myotis) can easily discriminate between individuals based on their echolocation calls and that they can generalize their knowledge to discriminate new individuals that they were not trained to recognize. We conclude that, despite their high variability, broadband bat-echolocation calls contain individual-specific information that is sufficient for recognition. An analysis of the call spectra showed that formant-related features are suitable cues for individual recognition. As a model for the bat's decision strategy, we trained nonlinear statistical classifiers to reproduce the behaviour of the bats, namely to repeat correct and incorrect decisions of the bats. The comparison of the bats with the model strongly implies that the bats are using a prototype classification approach: they learn the average call characteristics of individuals and use them as a reference for classification.

Foraging bats avoid noise

Ambient noise influences the availability and use of acoustic information in animals in many ways. While much research has focused on the effects of noise on acoustic communication, here, we present the first study concerned with anthropogenic noise and foraging behaviour. We chose the greater mouse-eared bat (Myotis myotis) as a model species because it represents the especially vulnerable group of gleaning bats that rely on listening for prey rustling sounds to find food (i.e. 'passive listening'). In a choice experiment with two foraging compartments, we investigated the influence of background noise on foraging effort and foraging success. We tested the hypotheses that: (1) bats will avoid foraging areas with particularly loud background noise; and (2) the frequency-time structure of the noise will determine, in part, the degree to which it deters bats. We found a clear effect of the type of noise on the allocation of foraging effort to the compartments and on the distribution of prey capture events. When playing back silence, the bats made equal use of and were equally successful in both compartments. In the other three treatments (where a non-silent sound was played back), the bats avoided the playback compartment. The degree to which the background noise deterred bats from the compartment increased from traffic noise to vegetation movement noise to broadband computer-generated noise. Vegetation noise, set 12 dB below the traffic noise amplitude, had a larger repellent effect; presumably because of its acoustic similarity with prey sounds. Our experimental data suggest that foraging areas very close to highways and presumably also to other sources of intense, broadband noise are degraded in their suitability as foraging areas for such 'passive listening' bats.

Variation in Ectoparasite Load Reflects Life History Traits in the Lesser Mouse-eared Bat Myotis blythii (Chiroptera: Vespertilionidae) in Western Iran

We studied seasonal variation of ectoparasite load (number of parasites per individual bat) in free-ranging populations of the lesser mouse-eared bat Myotis blythii in western Iran. Data for 1 species each of batfly (Nycteribidae), tick (Ixodidae), and mite (Spinturnicidae) are reported for a 1 yr period. Patterns of parasite load during this time differed considerably among species. However, the parasite load increased markedly in pregnant females in spring and early summer. During the same time frame, parasite load decreased in solitary males when they roosted apart from maternity clusters. However, in late summer, when bats began swarming, males showed a significant (P < 0.05) increase in parasite load. Using the ratio of body mass to length of forearm as an index of body condition, no significant correlation was found.

Italy as a major Ice Age refuge area for the bat Myotis myotis (Chiroptera: Vespertilionidae) in Europe

The distribution of biota from the temperate regions changed considerably during the climatic fluctuations of the Quaternary. This is especially true for many bat species that depend on warm roosts to install their nursery colonies. Surveys of genetic variation among European bats have shown that the southern peninsulas (Iberia and the Balkans) harbour endemic diversity, but to date, no such surveys have been conducted in the third potential glacial refuge area, the Apennine peninsula. We report here the phylogeographical analysis of 115 greater mouse-eared bats (Myotis myotis) sampled throughout Italy, and show that 15 of the 18 different haplotypes found in the mitochondrial control region of these bats were unique to the Apennine peninsula. Colonies within this region also showed substantial genetic structure at both mitochondrial (Phi(ST) = 0.47, P < 0.001) and nuclear markers (F(ST) = 0.039, P < 0.001). Based on a comprehensive survey of 575 bats from Europe, these genetic markers further indicate that central Italian populations of M. myotis are more closely related to Greek samples from across the Adriatic Sea, than to other Italian bats. Mouse-eared bat populations from the Apennine peninsula thus represent a complex mixture of several endemic lineages, which evolved in situ, with others that colonized this region more recently along an Adriatic route. Our broad survey also confirms that the Alps represent a relatively impermeable barrier to gene flow for Apennine lineages, even for vagile animals such as bats. These results underline the conservation value of bats from this region and the need to include the Apennine peninsula in phylogeographical surveys in order to provide a more accurate view of the evolution of bats in Europe.

First record of four species of bats from the nationale park of El Feidja (NW Tunisia) with a note on the non-flying mammals of the Khroumiria region

During a field study carried out in the Tunisian National Park of El Feidja (Khroumiria region, NW Tunisia) in May 2000, we captured four species of bats never previously recorded in this area: the Mediterranean horseshoe bat Rhinolophus euryale, the greater horseshoe bat R. ferrumequinum, the Mehely's horseshoe bat R. mehelyi and the Geoffroy's bat Myotis emarginatus. Considering the already well-known diffusion of the Schreibers' bat Miniopterus schreibersi, the common pipistrelle, Pipistrellus pipistrellus, the lesser mouse-eared bat Myotis blythi and the greater mouse-eared bat Myotis myotis, these new records raise to 8 the species of bats known for the region. The mammalians' checklist of the Khroumiria region includes 27 species.

A preliminary survey of cave-dwelling bats in a regional natural park of central Italy

The present work was carried out in the Gola della Rossa and Frasassi Natural Park (central Italy) between May 2004 and December 2006. Eleven species of bats were found and five colonies were identified and monitored in four different caves. Two neighbouring reproductive colonies of Schreiber's bat (Miniopterus schreibersii) and of greater and lesser mouse-eared bats (Myotis myotis/blythii) were found in the same cave (Grotta della Beata Vergine di Frasassi); a nursery colony of the Mediterranean horseshoe bat (Rhinolophus euryale) was found in another cave (Grotta del Fiume). The Schreiber's bat colony, hosting up to 11,280 adult individuals, appears to be amongst the largest ones so far recorded in central Italy.

Aggressive behaviour of greater mouse-eared bat (Myotis myotis) towards lesser horseshoe bats (Rhinolophus hipposideros) in a hibernaculum

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Terminal nerve in the mouse‐eared bat (Myotis myotis): Ontogenetic aspects

As in other mammals, ontogenesis of the terminal nerve (TN) in the mouse-eared bat (Myotis myotis) starts shortly after the formation of the olfactory placode, a derivative of the ectoderm. During development of the olfactory pit, proliferating neuroblasts thicken the placodal epithelium and one cell population migrates toward the rostroventral tip of the telencephalon. Here they accumulate in a primordial terminal ganglion, which successively divides into smaller units. Initial fibers of the TN can be distinguished from olfactory fibers in the mid-embryonic period. The main TN fiber bundle (mfb) originates from the anteriormost ganglion in the nasal roof, whereas one or more inconstant smaller fiber bundles (sfb) originate from one or more smaller ganglia in the basal part of the rostral nasal septum. The fibers of the mfb and sfbs join in the posterior quarter of the nasal roof before reaching the central ganglion (M) located in the meninges medial to the olfactory bulb. From the mid-fetal period onward, a thin TN fiber bundle with some intermingled perikarya connects M to the brain by penetrating its wall rostral to the olfactory tubercle. Additional smaller ganglia may occur in this region. The TN and its ganglia persist in postnatal and adult bats but the number of perikarya is reduced here. Moreover, the different potential functions of the TN are discussed briefly.

Environmental conditions, rather than season, determine torpor use and temperature selection in large mouse-eared bats (Myotis myotis)

We tested whether food availability, thermal environment and time of year affect torpor use and temperature selection in the large mouse-eared bat (Myotis myotis) in summer and winter. Food-deprived bats were torpid longer than bats offered food ad libitum. Bats placed in a gradient of low (0 degrees C-25 degrees C) ambient temperatures (T(a)) spent more time in torpor than bats in a gradient of high (7 degrees C-43 degrees C) T(a)'s. However, we did not observe seasonal variations in the use of torpor. Moreover, even when food deprived in winter, bats never entered prolonged torpor at T(a)'s characteristic of their natural hibernation. Instead, bats preferred shallow torpor at relatively high T(a), but they always maintained a difference between body and ambient temperatures of less than 2 degrees C. Calculations based on respirometric measurements of metabolic rate showed that food deprived bats spent less energy per unit of time in torpor than fed individuals, even when they entered torpor at higher T(a)'s. We conclude that T(a) likely serves as a signal of food availability and daily torpor is apparently an adaptation to unpredictable changes in food availability, such as its decrease in summer or its increase in winter. Thus, we interpret hibernation to be a second step in the evolution of heterothermy in bats, which allows survival in seasonal environments.

Comments on Welwitsch's mouse-eared bat ( Myotis welwitschii) with the first record from Cameroon

Comments on Welwitsch's mouse-eared bat ( Myotis welwitschii) with the first record from Cameroon

Postnatal growth in Myotis blythii (Chiroptera, Vespertilionidae)

The length of the forearm, the body mass and the length of the total gap of the fourth metacarpal-phalangeal joint were measured in order to develop empirical growth curves for a free-ranging population of the lesser mouseeared bat Myotis blythii in a maternity colony in western Iran. Length of forearm and body mass followed a linear pattern of growth until day 14 (at mean rates of 1.44 mm/day and 0.43 g/day respectively), and subsequently decreased to reach a stable level. The length of the total gap of the metacarpalphalangeal joint increased up to 10 days and decreased when it closed at over 70 days. Initiation of flight occurred 3-4 weeks after birth. A method of estimation of age was derived from values of length of forearm and the total gap of the fourth metacarpal-phalangeal joint during the preflight and post flight periods.

New lyssavirus genotype from the Lesser Mouse-eared Bat (Myotis blythi), Kyrghyzstan.

The Aravan virus was isolated from a Lesser Mouse-eared Bat (Myotis blythi) in the Osh region of Kyrghyzstan, central Asia, in 1991. We determined the complete sequence of the nucleoprotein (N) gene and compared it with those of 26 representative lyssaviruses obtained from databases. The Aravan virus was distinguished from seven distinct genotypes on the basis of nucleotide and amino acid identity. Phylogenetic analysis based on both nucleotide and amino acid sequences showed that the Aravan virus was more closely related to genotypes 4, 5, and—to a lesser extent—6, which circulates among insectivorus bats in Europe and Africa. The Aravan virus does not belong to any of the seven known genotypes of lyssaviruses, namely, rabies, Lagos bat, Mokola, and Duvenhage viruses and European bat lyssavirus 1, European bat lyssavirus 2, and Australian bat lyssavirus. Based on these data, we propose a new genotype for the Lyssavirus genus.

Energy balance of hibernating mouse-eared bat Myotis myotis: a study with a TOBEC instrument

Energy balance of hibernating mouse-eared bat Myotis myotis: a study with a TOBEC instrument