Karyotypes and Meiosis of the Morabine Grasshoppers IV.* The Genus Geckomima

Abstract

Of the 12 species of Geckomima, cytological material of only six has been available for study. All these are XO in the male sex. Most of them show the primitive morabine karyotype of 2n*female = 17 (metacentric X, metacentric AB and CD autosomes, six pairs of small acrocentric autosomes). However, G. pilbara has the AB chromosome dissociated into two acrocentric elements 'A' and 'B' (dissociation D11); and the most northerly individual of G. arnhemana has two different fusions (F21 and F22) between small chromosomes, thereby reducing the chromosome number to 2n*female = 13. Assuming that a northern race with this karyotype exists, it should be separated from the southern race by a rather strong chromosomal isolating mechanism.