Karyotype and meiosis analysis of four species of Cameroonian Pyrgomorphidae (Orthoptera)

Abstract

In this article, the karyotypic features (chromosome number, morphology, size and length and length of X chromosome), and meiosis in Atractomorpha lata, Dictyophorus griseus, Taphronota thaelephora and Zonocerus variegatus (Orthoptera: Pyrgomorphidae: Pyrgomorphinae) were analysed in order to determine similarities and differences amongst them. All four species were cytogenetically similar in relation to chromosome number, morphology and sex mechanism. They revealed karyotypes that comprised of acrocentric chromosomes with complement number 2n = 19 (male) and the XX♀-XO♂ sex mechanism. Chromosomes in the four species occurred in size groups of long, medium and short. The number of chromosomes in the size groups varied with species. Cluster analysis revealed chromosomes 4, 5 and 9 to be comparable in length in all four species and it is suggested that these chromosomes could be marker chromosomes for the subfamily Pyrgomorphinae. The meiotic process in the four species was normal and chiasmate. Similar bivalent shapes were recognized for both Diplotene and first meiotic Metaphase in the four species. Mean chiasma frequency was not significantly different (P>0.05) for A. lata, D. griseus, T. thaelephora but was significantly higher (P< 0.05) for Z. variegatus compared to the other three species.