Activity patterns of the lesser horseshoe bat Rhinolophus hipposideros at summer roosts

Dusk to dawn observations, using a bat detector and occasionally an image intensifier, were made outside two nursery roosts of lesser horseshoe bats Rhinolophus hipposideros from late May to September. Emergence was correlated with sunset but delayed by extended twilight. Light intensity was important in triggering departure and cloud cover advanced it. Light-testing behaviour was invariably undertaken, in the form of brief flights out and back into the roosts. The exit from one roost was shaded by trees and exploratory flights were generally more extended there. Heavy rain inhibited emergence. There was almost always intermittent activity throughout the night, with many individuals returning and departing, and no indication of seasonal or overnight peaks. A bat detector inside a third roost confirmed overnight observations at the other two. Some bats often returned to the roost for the night before dawn. Dawn return was linked to sunrise, prolonged twilight in midsummer hastening it. Colony size varied appreciably over periods of a few days and even overnight. There is some limited evidence that increased colony size, perhaps through social interaction, may have influenced timing of departure at dusk and return at dawn.     

Analysis of the diet of the lesser horseshoe bat Rhinolophus hipposideros in the West of Ireland

The diet of the lesser horseshoe bat Rhinolophus hipposideros was investigated over one season by analysing faeces and discarded insect fragments collected on polythene sheets at eight roosts. Remains of 23 insect families from seven orders (Lepidoptera, Neuroptera, Trichoptera, Hymenoptera, Coleoptera, Diptera and Hemiptera) and of spiders (Araneae: Arachnida) were identified. Nematoceran Diptera were the chief prey but Lepidoptera, Trichoptera and Neuroptera were also important. Both locational and seasonal variation were demonstrated for some food categories. The predicted seasonal availability of the different insect taxa is broadly reflected in the results: the question of possible prey selection is discussed. The bat fed successfully on three families of Lepidoptera known to possess hearing organs sensitive to bat ultrasounds. The possible mechanisms by which R. hipposideros might catch such prey are reviewed.     

Characterization of 14 polymorphic microsatellite loci for the lesser horseshoe bat,Rhinolophus hipposideros (Rhinolophidae,Chiroptera)

Fourteen polymorphic microsatellites isolated in the lesser horseshoe bat, Rhinolophus hipposideros, are described. A subset of eight loci successfully coamplified in a multiplex polymerase chain reaction (PCR), and allowed to confirm that expected heterozygosity was relatively high for the eight loci (0.56–0.83). This set of eight microsatellites indeed permits to build genetic tags that distinguish all individuals in colonies consisting of up to more than 1000 individuals.     

Impact of predation by a cave-dwelling bat, Rhinolophus ferrumequinum, on the diapausing population of a troglophilic moth, Goniocraspidum preyeri

The predation pressure of the greater horseshoe bat, Rhinolophus ferrumequinum, on the diapausing population of the noctuid moth, Goniocraspidum preyeri, was examined at an abandoned mine in central Japan. These bats did not prey on the moths in summer. The number of moths preyed on was largest in March. More than 60% of the diapausing moths were eaten by only three or four bats, which accounted for over 90% of all the moth deaths. This moth was an important source of food at the end of the hibernating period when the bat had already used most of its stored subcutaneous fat. The predation on G. preyeri may have raised the overwintering success rate of R. ferrumequinum.     

Calibrated earphones for the echolocating bat,Rhinolophus ferrumequinum

Summary A method to construct and calibrate earphones (physiologically) suitable for small bats and probably other small mammals is described. Particular emphasis was placed on getting a flat frequency response curve between 75kHz and 110kHz, the most important range forRhinolophus ferrumequinum. Below 60kHz the slope declined by about 30dB down to the audible frequency range. The maximal output without harmonic distortion (30dB down) was 80–90dB SPL, but up to 115dB SPL could be attained when accepting harmonics.Supported by the grants: Stiftung Volkswagenwerk, 111858; Deutsche Forschungsgemeinschaft, Schl 117/4; Schn 138/6     

人为干扰强度对村级景观破碎度的影响

村落具有人类活动所造成的许多景观特征,是研究人为干扰对景观破碎度影响的良好场所;本文运用地表植被的改变状况和主要辅助能的投入为指标,按重度干扰强度、中度干扰强度和轻度干扰强度3个等级把村落分为中心区、过渡区和基质区,分别不同研究区的景观破碎度与人为干扰强度的相互关系,3个研究区域的斑块密度指数分别为0．3416、0．3109和0．0028;景观破碎度分别为0．0820、0．0746和0．0007,重度干扰和中度干扰比轻度干扰下景观具有明显高的斑块密度指数和破碎化指数,随着人为干扰强度的增加,景观破碎化程度相应增加,中度人为干扰使景观破碎度值较高。     

Phylogeography and postglacial recolonization of Europe by Rhinolophus hipposideros: evidence from multiple genetic markers

The demographic history of Rhinolophus hipposideros (lesser horseshoe bat) was reconstructed across its European, North African and Middle‐Eastern distribution prior to, during and following the most recent glaciations by generating and analysing a multimarker data set. This data set consisted of an X‐linked nuclear intron (Bgn; 543 bp), mitochondrial DNA (cytb‐tRNA‐control region; 1630 bp) and eight variable microsatellite loci for up to 373 individuals from 86 localities. Using this data set of diverse markers, it was possible to determine the species’ demography at three temporal stages. Nuclear intron data revealed early colonization into Europe from the east, which pre‐dates the Quaternary glaciations. The mtDNA data supported multiple glacial refugia across the Mediterranean, the largest of which were found in the Ibero‐Maghreb region and an eastern location (Anatolia/Middle East)–that were used by R. hipposideros during the most recent glacial cycles. Finally, microsatellites provided the most recent information on these species’ movements since the Last Glacial Maximum and suggested that lineages that had diverged into glacial refugia, such as in the Ibero‐Maghreb region, have remained isolated. These findings should be used to inform future conservation management strategies for R. hipposideros and show the power of using a multimarker data set for phylogeographic studies.     

Directional sensitivity of echolocation in the horseshoe bat,Rhinolophus ferrumequinum

Summary The directionality of sound emission by a horseshoe bat (Rhinolophus ferrumequinum) has been determined for the constant frequency component of its orientation sounds. The bat was fixed in the center of an acoustic perimeter and the SPL of the orientation sounds measured with a scanning microphone at different angles compared with the SPL measured by another microphone located in the direction perpendicular to the plane of the horseshoe-like structure of the nose-leaf. The maximum SPL was always found in this direction which also corresponds to the flight direction of a bat in horizontal flight. Above and lateral to this direction the SPL decreases steadily with -6 dB-points at 24 above and 23 lateral. Below the flight direction we found a prominent side lobe with a -6 dB-point at 64 .When the present data are combined with measurements of the behavioral directionality of hearing at the same frequency (Grinnell and Schnitzler, 1977), the directionality diagram of the entire echolocation system is very narrow and points in the flight direction. The prominent downward side lobe of emission does not conspicuously increase echolocation effectiveness in the direction of the ground, since hearing sensitivity is falling off so steeply in that direction. However, without this downward beam of emission, signals from below the bat would be that much less effective.Interference with the structure of the nose-leaf by covering the upper part with vaseline or plugging the left nostril destroyed the smoothness of the normal sound field and demonstrated that this complex organ is a highly functional structure optimized in the course of evolution.With differences in mood or attention, the emitted pulses varied by as much as 20 dB (80–100 dB). The emission directionality pattern also varied. In most cases, as orientation sounds increased in SPL, the acoustic beam became smaller.Supported by Deutsche Forschungsgemeinschaft, grant No. Schn 138/1-6, Stiftung Volkswagenwerk, grant No. 111 858, and the Alexander von Humboldt StiftungWe thank W. Hollerbach and C. Nitsche for technical assistance.     

Life in a mosaic landscape: anthropogenic habitat fragmentation affects genetic population structure in a frugivorous bat species

Bats are often considered highly mobile and hence less susceptible to habitat fragmentation than other animals. We tested this basic assumption by studying populations of Dermanura watsoni, a frugivorous phyllostomid bat, inhabiting forest fragments in an agriculturally dominated landscape in northeastern Costa Rica. We used the mitochondrial D-loop DNA-sequence data to examine genetic diversity and population structure. A significant population differentiation (F _ST  = 0.05, p < 0.001) over a geographical scale of approximately 20 km was detected. Genetic diversity within fragments correlated with patch size and the amount of suitable habitat in the surrounding matrix. The composition of the matrix in close proximity to the fragments explained variation in genetic diversity best. However, only habitat parameters measured from 1986 land cover conditions can explain current genetic diversity, and not those from 2001. Our study demonstrates that bats, despite their high mobility, are not secure from genetic erosion in anthropogenically modified landscapes. Population differentiation can occur on a surprisingly small geographic scale and after short time periods. Our findings illustrate the importance of considering several points in time when testing for an influence of habitat parameters as it might be decades until they are reflected by genetic diversity.     

Studies on the vaginal plug of the Japanese greater horseshoe bat, Rhinolophus ferrumequinum nippon

The vaginal plug of the Japanese greater horseshoe bat is composed of an outer, thick, hard and homogeneous layer originating from the stratum disjunctum of the vaginal mucosa and a thin, soft and opaque central core containing accidentally trapped dead spermatozoa. The vaginal plug appeared to be expelled just before or after ovulation in spring. Immediately after copulation in autumn, uterine spermatozoa were dead but few leucocytes were present. As time passes after copulation, however, the infiltration of leucocytes into the uterus increased gradually, and extensive leucocytic phagocytosis of dead spermatozoa occurred during hibernation.     

Control of doppler shift compensation in the greater horseshoe bat,Rhinolophus ferrumequinum

Summary FlyingRhinolophus ferrumequinum lower the frequency of the constant frequency part (f _A ) of the emitted sounds in order to compensate for Doppler shifts caused by the flight speed. The echo frequency (f _E ) is kept constant within a frequency band of about 200 Hz, the center frequency of which is about 150 Hz above the average or resting frequency (f _R ) emitted by roosting bats shortly before take off. For the compensation they use a feedback control system in which the emission frequency is changed to hold the echo frequency at a criterion value. This feedback system was demonstrated by experiments with bats flying in an experimental wind tunnel and in a He-O₂-micture. In the wind tunnelRhinolophus lowers the emission frequency in order to compensate for Doppler shifts which are caused by the ground speed flown by the bat. In the He-O₂-mixtureRhinolophus compensates for Doppler shifts which correspond to the different sound speeds in the gas mixture.I would like to thank D. R. Griffin for his generous support and stimulating criticism. I express my appreciation to the New York Zoological Society for the use of its facilities and to R. Brown for technical assistance. The work was supported by grant number GB 7155 from the National Science Foundation to the New York Zoological Society. I also thank J. D. Pye for his suggestions.