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Open Access Research

What mechanism of niche segregation allows the coexistence of sympatric sibling rhinolophid bats?

Egoitz Salsamendi1, Inazio Garin1, Inmaculada Arostegui2, Urtzi Goiti1 and Joxerra Aihartza1*

Author Affiliations

1 Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Sarriena z/g, Leioa E-48940, The Basque Country

2 Department of Applied Mathematics, Statistics and Operational Research, Faculty of Science and Technology, University of the Basque Country UPV/EHU, Sarriena z/g, Leioa E-48940, The Basque Country

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Frontiers in Zoology 2012, 9:30  doi:10.1186/1742-9994-9-30

Published: 13 November 2012

Abstract

Introduction

Our purpose was to assess how pairs of sibling horseshoe bats coexists when their morphology and echolocation are almost identical. We collected data on echolocation, wing morphology, diet, and habitat use of sympatric Rhinolophus mehelyi and R. euryale. We compared our results with literature data collected in allopatry with similar protocols and at the same time of the year (breeding season).

Results

Echolocation frequencies recorded in sympatry for R. mehelyi (mean = 106.8 kHz) and R. euryale (105.1 kHz) were similar to those reported in allopatry (R. mehelyi 105–111 kHz; R. euryale 101–109 kHz). Wing parameters were larger in R. mehelyi than R. euryale for both sympatric and allopatric conditions. Moths constitute the bulk of the diet of both species in sympatry and allopatry, with minor variation in the amounts of other prey. There were no inter-specific differences in the use of foraging habitats in allopatry in terms of structural complexity, however we found inter-specific differences between sympatric populations: R. mehelyi foraged in less complex habitats. The subtle inter-specific differences in echolocation frequency seems to be unlikely to facilitate dietary niche partitioning; overall divergences observed in diet may be explained as a consequence of differential prey availability among foraging habitats. Inter-specific differences in the use of foraging habitats in sympatry seems to be the main dimension for niche partitioning between R. mehelyi and R. euryale, probably due to letter differences in wing morphology.

Conclusions

Coexistence between sympatric sibling horseshoe bats is likely allowed by a displacement in spatial niche dimension, presumably due to the wing morphology of each species, and shifts the niche domains that minimise competition. Effective measures for conservation of sibling/similar horseshoe bats should guarantee structural diversity of foraging habitats.

Keywords:
Chiroptera; Coexistence; Diet; Foraging habitat; Morphology; Sibling species; Rhinolophus