Rapporto sessi in Mesobuthus gibbosus (Scorpiones Buthidae).

The sex ratio of M. gibbosus was studied, based on 320 specimens collected at 25 sites in Greece: 21 from the Peloponnesus and 4 from the island of Crete. To discriminate among sexes, pectinal tooth number was utilized. To verify the usefulness of this character, the presence or absence of genital papillae, a character unique to males, was checked. Scanning electron microscopy (SEM) photographs of genital papillae and genital opercula of the species are presented. These structures are very similar, to all appearance, to that of Buthus occitanus observed by light stereomicroscopy. Among the protonymphs and deutonymphs, the sex ratio was not significantly different from 1:1. The sex ratio of the sample of larger individuals (considered to be adults) from the Peloponnesus was 1:3.36 in favour of females; the difference from the expected ratio 1:1 was highly significant in the CHI 2 test (P=0.01). The sex ratio of M. gibbosus from the Peloponnesus is critically compared with the sex ratio of a sample from Pindos, northern Greece, which was analysed previously. Temporal and spatial variation in the sex ratio is supposed.