Published online by Cambridge University Press: 28 February 2007
The nature, number, structure and behaviour of chromosomes during the meiotic and mitotic sequences in the armoured ground cricket, Acanthoplus speiseri Brancsik, were investigated from testicular and ovariole material. The karyotype of A. speiseri is 2n ♂=25 (24 autosomes + XO) and 2n ♀=26 (24 autosomes + XX). The species exhibits the primitive XO ♂ /XX ♀ type of sex determination mechanism. All chromosomes in the cell complement (including the X sex chromosome), in both sexes, are acrocentric in shape. The X sex chromosome is the largest element in the karyotype while the autosomes comprise three large, four medium and five small pairs. The behaviour of the chromosomes during the meiotic and mitotic processes is normal and typically orthopteran. The study discusses the important role that karyology and cytogenetics can play for species diagnostics in the subfamily Hetrodinae.