Sexual and age size variation in the western Palaearctic populations ofMiniopterusbats (Chiroptera: Miniopteridae)

Abstract

Among populations of the Miniopterus bats of western Palaearctic, intraspecific variation has not been well documented. Herein we investigate sexual and age variation of these populations using two approaches — linear and geometric morphometrics. We analysed Moroccan (M. maghrebesnis), western and eastern European (M. schreibersii), Levantine (M. schreibersii), and east-Afghanistani (M. cf. fuliginosus) specimens; variation was compared between sexes of the particular specimen sets of three above mentioned Miniopterus spp. and between four age cohorts of M. schreibersii samples. The results showed in all examined population sets males to be generally larger in size than females, the exception being the east-European animals. Significatly the most divergent sexes were those from eastern Afghanistan, the Levant and eastern Europe. The differences found between sexes in as well as between examined population sets can be attributed to different life histories and/or to food competition. Weak correlations between patterns of sexual dimorphism and the newly proposed western Palaearctic classification of the Miniopterus bats suggest only a limited contribution of sexual variation to morphological variation in general. Certain aspects of age variaton were found in all examined morphological characters except the non-metric traits, which in turn indicates the importance of these traits for identification of the particular taxon across age categories.