Karyological studies of Metrioptera arnoldi Rme (decticidae) and Ancistrura nigrovittata (Br.) (Phaneropteridae: Tettigonioidea-Orthoptera)

Abstract

The karyotype of Metrioptera amoldi Rme and Ancistrura nigrovittata (Br.) is described. Both species possess the primitive character of karyotype (2n = 31♂, all chromosomes are acrocentric, XO and XX sex determining mechanism). A small number of chiasmata were found, Metrioptera amoldi having two or three in L and one in M and S, while Ancistrura nigrovittata has only one chiasma in all bivalents. Both species have non-homologous association between X and small autosomes and association between different large middle M and S chromosomes. The karyotype of Metrioptera arnoldi is much more flexible than that of Ancistrura nigrovittata. In Metrioptera amoldi the chromosomes of pairs L1, L2, and M5show diferences in staining in the length and thickness of terminal elements of bivalents. Metrioptera amoldi is compared in its karyological aspects with 3 other species belonging to the genus Metrioptera. © 1987 by the Japan Society for Bioscience, Biotechnology, and Agrochemistry.