Acoustic characterization of bats from Malta: setting a baseline for monitoring and conservation of bat populations

Mitochondrial Genetic Diversity of Bat Species from the Maltese Islands and Applications for their Conservation

“…Such distinct mitochondrial lineages, revealed for the latter two species, represent a relatively isolated allopatric lineage and may indicate reduced female gene flow between Malta and neighbouring islands and mainland. Despite that evidence from previous studies suggest incomplete isolation of the Maltese P. pipistrellus lineage (Hulva et al, 2010), the use of higher echolocation peak frequencies by both species (Mifsud & Vella, 2018) may be the result of enhanced local adaptation through limited gene flow (Puechmaille et al, 2011). The genetically distinct populations of these species, together with their observed sensory divergence allow for these populations to be delimited as separate conservation units as they represent unique genetic diversity and hence deserve higher conservation priority.…”

“…One of the latest published research on bats from Malta has confirmed through acoustic and morphological analyses the presence of six resident bat species (Mifsud & Vella, 2018) representing species within genera which showed signs of cryptic diversity when studied across the Western Palaearctic using molecular techniques (Ibáñez et al, 2006;Spitzenberger et al, 2006;Mayer et al, 2007;García-Mudarra et al, 2009;Bogdanowicz et al, 2015). Previous acoustic surveys of bats from Malta revealed sensory divergence for the species Pipistrellus pipistrellus and Rhinolophus hipposideros when compared to their mainland conspecifics (Mifsud & Vella 2018), and therefore the addition of molecular data to the morphological and acoustic data available would further uncover the evolutionary significance of bat populations present in the Maltese Islands.…”

Plecotus austriacus Species Complex (P. austriacus, P. kolombatovici, P. gaisleri, P. teneriffae)

“…In Tunisia, start frequency ranges between 31.5 and 58.9 kHz (Dalhoumi et al 2016). On Malta, based on data from 14 P. gaisleri bats, average frequency of maximum energy is slightly lower (30.5 ±1.9 kHz; range 25 -33 kHz), though both start (44.8 ±2.9 kHz) and end frequencies (23.7 ±1.7 kHz) are higher, and average call duration is longer (2.1 ±1.1 ms) (Mifsud and Vella 2018).…”

“…Average call values in Morocco are all lower than in P. austriacus, and are instead closer to values reported for P. christii from North-East Africa (Benda et al 2010). However, although P. gaisleri has slightly lower frequency of maximum energy and end frequency and shorter call duration than P. austriacus, echolocation calls are similar, and therefore the two species cannot be distinguished without additional morphological measurements (Mifsud and Vella 2018).…”

“…gaisleri weighs between 6 and 9.5 g (average 7.49 ±0.9 g [n=14]) on Malta (Mifsud and Vella 2018). Forearm length range between 35.8 and 41.8 mm across the species range, with an average of 38.89 ±1.2 mm (n=41) in Libya,39.46 ±1.3 mm (n=14) in Algeria,40.21 ±1 mm (n=11) in Morocco (Benda et al 2014), 39.33 ±0.6 mm (n=3) in Tunisia (Dalhoumi et al 2015), and 38.84 ±3.4 mm (n=14) on Malta (Mifsud and Vella 2018). Hind foot length is on average 8.6 mm (range 8 -9 mm; n=14) (Benda and Aulagnier 2013).…”