Search

Flycatching is relatively uncommon in insectivorous bats, yet members of the family Rhinolophidae constitute over one-half of the documented flycatching species. The Formosan woolly horseshoe bat, Rhinolophus formosae, is among the largest in size and relies primarily on flycatching for foraging. We assessed perch use of flycatching R. formosae in relation to vegetation structure in tropical monsoon forests in southern Taiwan. We located bats using acoustic detectors in forest interior and edge-open forest sites, and measured perch features, dispersion of the nearest trees, and vegetation structure within a 5-m radius of each perch. The same measurements were applied to randomly selected perches in both habitats where bats were not detected. We found no seasonal effects or differences between used and random perches in perch features, dispersion of neighboring trees, or vegetation structure surrounding the perches. Perches used at edge-open forest sites were farther from the perch tree trunk and neighboring trees, and surrounded by larger trees than in forest interiors. In contrast, perches in forest interiors were surrounded by higher shrub and reef layers and greater canopy, shrub, and reef layer cover, than those at edge-open forests. Overall, perches in forest interiors were in more cluttered settings, containing higher vegetation obstacles than edge-open habitats. In both habitats, vegetation obstacles generally increased in a curvilinear manner when moving horizontally and downward from the perch. However, in forest interiors perches used by bats had significantly lower vegetation obstacles horizontally and downwardly and were less cluttered than randomly selected perches. Overall, our results indicate that R. formosae in forest interiors selectively used perches associated with more open space that allows for more maneuverable sally flights and a longer detection range suitable for its exceptionally low constant frequency calls to explore less cluttered environments.

A new species of horseshoe bat (Chiroptera: Rhinolophidae) is described from southwestern China. The presence of a wedge-shaped sella and pointed connecting process of the nose leaf aligns the new species to the landeri group in the Afro-Palearctic lineage of Rhinolophus. However, the new species is distinctly separable from these allopatrically distributed species by its noticeably larger body size. Other sympatric large-sized species of Rhinolophus have rounded connecting processes. Molecular systematic analyses based on mitochondrial cytochrome-b sequences confirmed the affinity of the new species to the Afro-Palearctic lineage, but in a clade most closely related to the ferrumequinum, fumigatus, and maclaudi groups. Of these species, only R. ferrumequinum ranges into Asia and overlaps in distribution with the new species. R. ferrumequinum is similar in general body size and external appearance; however, the new species is distinct in the characteristics of the nose leaf, skull, and baculum. The presence of a new species from southwestern China in the Afro-Palearctic lineage indicates a more complex historical biogeographic scenario within Rhinolophus than previously known. The difficulties found in allocating the new species to one of the phenetically described traditional species groups stress the convenience of using a phylogenetically based systematic organization of the genus Rhinolophus.

We studied the effect of habitat type and prey availability on the foraging decisions of the Mediterranean horseshoe bat (Rhinolophus euryale), a species specialized for cluttered environments. We modeled seasonal habitat selection using radiotelemetry in relation to prey availability in a heterogeneous landscape, determined seasonal diet and prey selection, and used geographic information system data to characterize the landscape surrounding 10 breeding colonies in order to assess the radiotracking results at the population level. Although R. euryale typically has been associated with woodland, our results suggest that the existence of edge habitat, created by semicluttered structures such as hedgerows and woodland edges, was a significant factor in the choice of foraging areas by these bats. Edge habitat was associated with meadows and pastures, creating a landscape highly suited to moths, the preferred prey of R. euryale. In the study area, however, moths were evenly distributed among habitat types; therefore, distribution of moths cannot explain the preference of these bats for semicluttered habitats. The results of our study are consistent with the presumed origin of R. euryale in an edge-rich ecosystem (i.e., the savannahs of northern Africa) and establish a new paradigm for how this species uses habitat. This new paradigm, which might also apply to other members of the genus in Europe, should prompt reconsideration of the presumed habitat requirements for this species, and should be incorporated into the conservation policies for the Mediterranean horseshoe bat.

Wing morphology is crucial for flight performance and foraging ecology in bats. We describe variations in 5 wing parameters within the 5 species of European horseshoe bats (genus Rhinolophus) based on data taken from 3,081 adult individuals. All 5 species belong to a single ecological guild. Measurements were taken from live bats in the field in southeastern Europe (Bulgaria, Greece, and Turkey), where all 5 species occur in sympatry. Examination of our data shows that the species and accordingly their wings differ substantially in size. Albeit grossly similar in form, we additionally found several size-independent differences in wing shape. For example, the smallest species, Rhinolophus hipposideros, and to a lesser extent also R. blasii, have extremely short hand wings, enabling highly maneuverable search flight close to vegetation. The largest species, R. ferrumequinum, and the 2nd largest one, R. mehelyi, have rather long hand wings, allowing fast and economic commuting flight over longer distances. We argue that both size and shape are likely to play a role for niche separation between species. We found both sexual and geographic variation within species. There was sexual dimorphism for most parameters, with females being larger than males. Populations of R. mehelyi in southeastern Europe had significant variation in wing measurements. This was not so for R. ferrumequinum and R. euryale. We give a discriminant function based on only 2 parameters that correctly assigned 98% of the 3,081 individuals to species. This function may prove useful for identification of museum specimens.

The vocal communication of Japanese greater horseshoe bats was analyzed by experimental separation of mothers and young. When separated from their mothers, infants first emitted broad-band “attractive calls” and the mother responded by emitting “lead signals.” During this process of mutual signalling, the acoustic character of the infants’ sounds and the mutual patterning of signal emission gradually and repeatedly changed. Finally, the high-pitched signals of mother and infant precisely overlapped until the pair was reunited. The vocal signals involved in mother-young communication were divided into two categories: 1) highly communicative signals such as “attractive calls,” “recognition calls,” and “contact calls”; and 2) basically echolocative but functionally communicative signals such as “lead signals” and “high-pitched signals.” It was not the physical structure of the signals, but their mutual patterning that seemed to be important in mother-infant communication. Analysis of these mutual signalling processes showed that either the mother or the infant or both coordinated their signals both temporally and phasically. In the final high-pitched stage, the mother emitted signals at a constant pitch while the infant changed pitch until attaining precise synchronization with the calls of the mother. The high-pitched synchronization with frequency coincidence of signals seemed to be essential for mother-infant communication.

A Japanese bat that uses constant frequency echolocation signals, Rhinolophus ferrumequinum nippon , has a close mother-infant relationship: the mother retrieves the young if it strays and returns to it after foraging. The breeding colonies are in dark caves, and infant vocalization may serve as a basis for mother-infant communication and recognition. Infant vocalization and its development were analyzed by separating mother-infant pairs of various ages and recording their vocalizations and behavior. Infants can emit oral and nasal calls. Vocal development consists of a shift from oral to nasal calls, low to higher frequencies, and noisy to pure tones. The shift occurs even within a syllable. Morphological perfection of the laryngo-nasal junction underlies vocal development.