CHROMOSOME STUDY OF SOME GRASSHOPPER SPECIES FROM DIFFERENT LOCALITIES IN CENTRAL ETHIOPIA

Abstract

Around 200 grasshopper species have been identified in Ethiopia, hitherto. The diversity and economic importance of Ethiopian grasshoppers notwithstanding, there is only few studies done on their taxonomy, distribution and ecology. Additionally, no report on the karyology of Ethiopian grasshoppers is available prior to this study. Hence, this research is aimed at studying the chromosomes of some Ethiopian grasshopper species. The grasshopper specimens used in this study were collected from eight localities in central Ethiopia. The specimens were identified as belonging to two families (Acrididae and Tetrigidae). Chromosome preparations were made from tissues of the whole gut and the testis following colchicine pretreatment of live insects. All the insects belonging to family Acrididae showed karyotypic similarity, with all having 2n = 23 (22 autosomes + x) in males and 2n = 24 (22 autosomes + xx) in females. Morphologically all the chromosomes were telocentrics except an acrocentric x chromosome observed in some of the taxa. Despite the overall karyotypic similarity, minor variations were also observed. In the genus Paratettix (Tetrigidae), the analyzed female specimen had 2n = 20 telocentric chromosomes. In the male specimen of genus Acanthacris, some chromosome numerical instability, involving hypodiploid and hyperdiploid conditions, were observed both in the meiotic and mitotic cells of the testis. Furthermore, an extra chromosome was observed in some of these cells and this was assumed to be a b chromosome. The need for further large-scale chromosome study of Ethiopian grasshoppers is recommended.