Non Banded and C-banded Karyotypes of Ten Species of Short Horned Grasshoppers (Acrididae) from South India

Abstract

SummaryThe non-banded and C-banded karyotypes of 10 species of South Indian short horned grasshoppers of the family Acrididae with diploid number 23 in males and 24 in females were studied. All the species except Dociostaurus species A. and Leva indica have shown telocentric chromosomes. Interspecific non-banded and banded karyotypic comparison and its evolutionary implications are discussed. Key words Acrididae, Grasshoppers, Chromosomes, Karyotype, C-banding.Karyotype forms the cytological basis of species identity. Acrididae is known for its karyotypic uniformity or conservatism. But the instances of karyotypic variation with respect to number and morphology of chromosomes are observed in natural populations, which will add to the evolutionary pattern of a species.One of the mechanisms of species differentiation is the C-banding of chromosomes. C-banding technique has proven very effective for chromosomal identification and characterization and the pattern of C-banding has been found to be characteristic for a species or at least to a group of species (Kalkman 1984). King and John (1980) have found a remarkable degree of C-band variation between many species of grasshoppers. In addition, Acrididae showed a C-band variation even within the same species (Shaw et al. 1976, John and King 1977.In the present paper the karyotype and the distribution of C-heterochromatin in 10 species of Acrididae are presented and the possible evolutionary significance has been discussed. Materials and methodsThe males and females of 10 species belonging to 3 sub families of Acrididae were collected in and around Mangalore University Campus, South India and chromosome preparations were made using hepatic caecae following the standard Colchicine-hypotonic-cell suspension-flame dry technique. The flame dried slides were treated for C-banding following the method of Sumner (1972) with little modifications. The chromosomes were classified after Levan et al. (1964) and appropriate karyotypes were constructed. Results and discussionThe somatic chromosome preparations of the species of Tryxalinae, Oedipodinae, Catantopinae in the Acrididae under study exhibited XX : XO pattern of sex determining mechanism.

C-banding characterization of centric fusion and heterochromatin polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)

“…Different patterns of constitutive heterochromatin are a frequent characteristic within the order Orthoptera (King and John 1980, Santos et al 1983, John et al 1985, Rufas et al 1985, Cabrero and Camacho 1986, Hota and Patnaik 1989, Rodríguez Iñigo et al 1993, Yadav and Yadav 1993, Mayra et al 2004, Warchałowska-Śliwa et al 2009, 2013). All these previous reports together with results presented here support the hypothesis that C-heterochromatin content and distribution is independent of other evolutionary chromosomal changes in Orthoptera.…”