Genetic isolation of insular populations of the Maghrebian bat, Myotis punicus, in the Mediterranean Basin

Abstract

Aim We investigate the population genetic structure of the Maghrebian bat, Myotis punicus, between the mainland and islands to assess the island colonization pattern and current gene flow between nearby islands and within the mainland. Location North Africa and the Mediterranean islands of Corsica and Sardinia. Methods We sequenced part of the control region (HVII) of 79 bats across 11 colonies. The phylogeographical pattern was assessed by analysing molecular diversity indices, examining differentiation among populations and estimating divergence time. In addition, we genotyped 182 bats across 10 colonies at seven microsatellite loci. We used analysis of molecular variance and a Bayesian approach to infer nuclear population structure. Finally, we estimated sex‐specific dispersal between Corsica and Sardinia. Results Mitochondrial analyses indicated that colonies between Corsica, Sardinia and North Africa are highly differentiated. Within islands there was no difference between colonies, while at the continental level Moroccan and Tunisian populations were highly differentiated. Analyses with seven microsatellite loci showed a similar pattern. The sole difference was the lack of nuclear differentiation between populations in North Africa, suggesting a male‐biased dispersal over the continental area. The divergence time of Sardinian and Corsican populations was estimated to date back to the early and mid‐Pleistocene. Main conclusions Island colonization by the Maghrebian bats seems to have occurred in a stepping‐stone manner and certainly pre‐dated human colonization. Currently, open water seems to prevent exchange of bats between the two islands, despite their ability to fly and the narrowness of the strait of Bonifacio. Corsican and Sardinian populations are thus currently isolated from any continental gene pool and must therefore be considered as different evolutionarily significant units (ESU).

Piecing the punicus Puzzle

“…Through PCR of the Second Hypervariable Domain (HVII) of the mitochondrial D-loop followed by sequencing, it was determined that only a single haplotype is present on the Maltese Islands (Baron, unpublished). It was recently possible to compare this data with haplotypes isolated from all over the Mediterranean Basin (Biollaz et al, 2010). Interestingly the closest haplotype was found in Tunisia showing that Malta could have been used as a route to the other Mediterranean islands.…”

“…The mitochondrial and microsatellite haplotypes from the Maltese Islands would not have any meaning had it not been for the detailed work carried out across the Mediterranean region by Biollaz et al (2010). In this study the authors set out to determine the population genetic structure of Myotis punicus and current patterns of gene flow between the islands of Corsica and Sardinia and their relationships with North African populations.…”

“…Over the past ten years the above knowledge about the genetics of Myotis punicus has been used to further expand on these analyses and confirm its segregation from Myotis myotis and Myotis blythii as well as confirm the range of its distribution, which covers the greater part of the Maghreb region from Morocco, through Algeria and Tunisia, up to Tripolitania in northwest Libya and northwards to the European islands of Malta, Corsica and Sardinia Mucedda & Nuvoli, 2000;Topál & Ruedi, 2001;Beuneux, 2004;Baron and Vella, 2010;Biollaz et al, 2010).…”

“…However, until recently, only limited microsatellite data for Myotis punicus was available . With the availability of microsatellite data from the other Mediterranean Islands to compare with (Biollaz et al, 2010), the microsatellite data collected in Malta could be put to more rigorous evaluation. A permit application has recently been approved to expand this study to sample individuals from as many roosts as possible and obtain a clearer and more complete picture of the variability throughout the Maltese archipelago in an attempt to answer questions related to allele frequency distribution and possible inferences of roost movements.…”

Actualización del inventario de quirópteros y refugios en Ceuta: primera cita de Pipistrellus pygmaeus en el norte de África

“…blythii o Eptesicus isabelinus/E. serotinus, separando genéticamente poblaciones del norte de África con las peninsulares (Arlettaz et al 1997, Castella et al 2000, Beuneux 2004, Garcia-Mudarra et al 2009, Juste et al 2009, Biollaz et al 2010. Algunos estudios genéticos han tratado de interpretar el papel de el Estrecho de Gibraltar como paso en la ruta migratoria y su papel durante la expansión de algunas especies después de la era glacial como Miniopterus schreibersii (Pereira et al 2009).…”