The study of karyotype, meiotic cell and sex chromosome behavior in male religious mantis (Mantis religiosa siedleckii (Linnaeus, 1758))

Abstract

Mitotic and meiotic studies of the male religious mantis, Mantis religiosa siedleckii (Linnaeus, 1758), from Chiang Mai Province in Thailand were investigated. The mitotic and meiotic chromosomes were prepared directly from male testis tissue by colchicine-hypotonic-fixation technique. Conventional Giemsa and silver-NOR staining techniques were applied to stain the chromosomes. The results showed that the diploid chromosome number of the male religious mantis, M. religiosa siedleckii, was 2n = 27 including 24 autosomes and 3 sex chromosomes. The types of sex chromosome observed were X₁ chromosome, X₂ chromosome and Y chromosome. We found that during prophase I the homologous chromosomes showed synapsis, which can be defined as the 12 bivalents and 1 trivalent. The trivalent was synapsis by end by end between X₁, X₂ and Y chromosomes. The metaphase II comprises 2 types that included 13 haploid chromosomes, one of which to be Y chromosome, and 14 haploid chromosomes with X₁ and X₂ chromosomes. We also observed distinctive nucleolar organizer regions (NORs) at the region adjacent to the long arms near the telomere of X₁ chromosome and short arms near the telomere of Y chromosome.
The karyotype formula of the male religious mantis was deduced as: 2n (27) = 24 autosomes + sex chromosomes X₁X₂Y