Chromosome counts in some high altitude Otiorhynchus Germ. species from Yugoslavia

SUMMARYChromosome numbers were recorded in eleven high altitude Otiorhynchus species from Yugoslavia. In nine specie (O. atripes, O. dryadis, O. speiseri, O. aurosignatus vlasuljensis, O. praecellens bosnarum, O. koritnicensis, O. alpicola atterimus, O. alpicola ssp., O. retifer, O. strumosus) chromosome numbers were found to be diploid: ♀, 2n = 20 +XX and ♂, 2n = 20 + XY, respectively. However, in two species, i.e., O. mendax and O. croaticus polyploid chromosome counts were observed. O. mendax populations consisted exclusively of tetraploid females (2n = 44), while O. croaticus comprised both male and female diploid and triploid female individuals (♀, 2n = 33). Since the coexistence of diploid and polyploid members within the same population is a rather rare event in the genus Otiorhynchus, the mechanism of origin of polyploid individuals was discussed.