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The distinctive structure of social calls by Hanak's dwarf bat Pipistrellus hanaki

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Georgiakakis P. , Russo D.

Acta Chiropterologica

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2012

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tom 14

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nr 1

XX

The analysis of social calls emitted by bats in the Pipistrellus genus has played an important role in assessing cryptic diversity and in investigating reproductive strategies and foraging ecology of these vespertilionids. Our study deals with social call structure of a recently discovered species, Pipistrellus hanaki. Because it shares a common ancestor with P. pygmaeus, we hypothesized that as in the other species from this group social call structure in P. hanaki retains the basic design observed in other bats from the same genus. We also hypothesized that as in other pipistrelles such calls fulfill context-dependent functions, being used by both foraging and mating bats for different purposes. However, we found that these calls have a structure rather different from that seen in most pipistrelles. Two different types of multi-harmonic, broad-band and long-duration social calls were identified, with distinctive temporal structures. Single component, frequency modulated-quasi constant frequency (FM-QCF) calls were emitted during summer at foraging sites where feeding buzzes were regularly produced. In autumn, when feeding buzz rates decreased and males caught at recording sites had prominent testes, a second type of single or multi-component calls with a fluctuating frequency over time was more frequent. Unlike the typical multi-component social calls recorded in several Pipistrellus species, our results suggest that social calls used by foraging or mating P. hanaki have markedly different structures. Because social calls of bats are speciesspecific and may function in reproductive isolation, we hypothesize that differentiation of social calls in P. hanaki has been associated with the divergence of this species from P. pygmaeus.

2

Coastal cliffs on islands as foraging habitat for bats

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Ancillotto L. , Rydell J. , Nardone V. , Russo D.

Acta Chiropterologica

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2014

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tom 16

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nr 1

EN

Small islands usually show simplified ecosystems with limited availability of suitable foraging habitats for bats, thus habitat selection on islands may differ compared to the mainland. Habitats that are marginal on the mainland may be important on islands. The island of Capri consists, to a large extent, of steep limestone cliffs and Mediterranean shrubland, with virtually no forests or other habitats preferred by bats on the mainland. In this study we tested the hypothesis that in resource-limited systems, such as islands, habitats generally deemed of minor value for bat foraging, such as cliffs, may become important. We conducted an acoustic survey of bats in Capri (SW Italy), comparing their use of Mediterranean shrubland and limestone cliffs. We found that cliffs provided the preferred foraging habitat in four of the five species tested. Noticeably, even the barbastelle bat Barbastella barbastellus, normally considered a forest specialist, selected coastal cliffs as foraging habitat. Our observations indicate that the paucity of foraging habitats on islands may strongly alter the habitat use by bats. This has important implications for conservation of bats in insular environments.

3

Habitat selection by Geoffroy's bats (Myotis emarginatus) in a rural Mediterranean landscape: implications for conservation

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Flaquer C. , Puig-Montserrat X. , Burgas A. , Russo D.

Acta Chiropterologica

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2008

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tom 10

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nr 1

EN

Most of the little information available on the foraging ecology of the threatened Geoffroy's bat Myotis emarginatus refers to areas outside the Mediterranean Basin. In this study, we analysed habitat selection by this species in a typical Mediterranean landscape. We radio-tracked a breeding colony (adults and juveniles) in the Iberian Peninsula and analysed habitat selection patterns. Although we confirmed the species' preference for forest, olive groves also appeared an important foraging habitat for both adults and juveniles. Juveniles proved to be less mobile than adults, moving on average 1.6 km less than adults in displacements to foraging sites and preferred more accessible habitats. We highlight here the importance of traditionally managed olive groves as foraging sites for this threatened bat. The ripping-up of ancient olive groves and their replacement by intensively managed cropland, urban areas or shrubland represents a significant threat for this vulnerable species in Mediterranean landscapes.

4

Habitat selection in Nathusius' pipistrelle (Pipistrellus nathusii): the importance of wetlands

61%

Flaquer C. , Puig-Montserrat X. , Goiti U. , Vidal F. , Curco A. , Russo D.

Acta Chiropterologica

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2009

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tom 11

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nr 1

EN

Wetlands are internationally recognized as a crucial habitat type for the conservation of many migratory birds. Despite the fact that many bats are also long-distant migrants, the importance of foraging habitats for sustaining migrant bats has to date received little attention. We analyzed habitat selection patterns in the migrant bat, Nathusius’ pipistrelle Pipistrellus nathusii, in the southernmost part of its range (Iberian Peninsula), an area in which both mating and hibernation occur. We found that natural wetlands and riparian habitats (Phragmites reed beds) were positively selected, whereas human-transformed aquatic habitats (rice paddies) were avoided. Although semi-natural human-managed wetlands are perceived as being valuable for many species, our data emphasizes the importance of preserving natural wetlands (including riparian forests) as appropriate habitats for sustaining crucial phases of the life cycle of this bat. Agricultural transformation of the land is likely to be detrimental to this species since it reduces the availability of its preferred foraging habitat.