Karyological studies of an Indian cricketMadasumma ventralisWalker (Orthoptera: Gryllidae)

Abstract

SUMMARY -Both mitotic and meiotic chromosomes of Madasumma ventralis were reported for the first time under the sub-family Podoscirtinae. Chromosomes prepared from the hepatic caeca cells and spermatogonial plates revealed within the same species 3 classes of karyotypes: Class-A with 2nc = 15, Class-B with 2nc = 14 and Class-C with 2n c = 13. These numerical differences were due to presence or absence of either one or both partners of chromosome pair 5. Different chromosomal combinations with 2nc = 15,14 or 13 were also observed in metaphase-I plates. TCL has been calculated to be 40.51 ~m. Unlike all other species of gryllids, X-chromosome was the 3rd largest in number and of sm-type.

Karyotype Plasticity in Crickets: Numerical, Morphological, and Nucleolar Organizer Region Distribution Pattern ofAnurogryllussp.

“…A less condensed chromatin region, usually heteromorphic and similar to that detected in pair 5 of Anurogryllus sp., was also encountered in one autosomal pair of other species of crickets ( Warchalowska-Sliwa 1980 ; Lamborot and Alvarez-Sarret 1985 ; Das and Das 1991 ; Zefa 1999 ; Mesa and Zefa 2004 ; Yoshimura 2005 ; Portugal and Mesa 2007 ). In Anurogryllus sp., the uncondensed chromatin region was representative of the NOR, considering that in all the studied specimens the short arm of both chromosomes of pair 5 was silver impregnated.…”

“…In general, these variations are result of chromosome rearrangements, such as translocations and centric fissions or fusions, which have mainly involved the autosomes and occasionally the sex chromosomes. Moreover, supernumerary chromosomes and extra chromosomal segments have also been registered in orthopteran species ( Hewitt 1979 ; Henriques-Gil et al 1984 ; López-Fernández et al 1984 ; Bhunya and Das 1985 ; Lamborot and Alvarez-Sarret 1985 ; Davenport 1986 ; Colombo 1987 ; Das 1989 ; Fossey et al 1989 ; Das and Das 1991 ; Mirol and Bidau 1991 ; Warchalowska-Sliwa et al 1992 ; Eugênio and Cella 1996 ; Zefa 1999 ; Colombo et al 2004 ). The mechanisms responsible for the chromosomal changes observed in orthopteran could have particular effects on karyotype evolution, taking into account that these could influence the frequency of recombination, fertility, and mating success ( Hewitt 1979 ; López-Fernández et al 1984 ; Colombo 1987 , 1993a , 1993b ; Fossey et al 1989 ; Colombo et al 2001 , 2004 ).…”

“…In Anurogryllus sp., a high level of chromosome polymorphism was observed, allowing the determination of five distinct karyotypes. Considering that karyotype 2n = 22 + X0 seems to be the basic type for the family Gryllotalpidae ( Hewitt 1979 ), which was recently determined to be a sister group to Gryllidae according to molecular data ( Jost and Shaw 2006 ), and considering that autosomes with acro/telocentric morphology are the most frequently detected in species of Gryllidae as well as in the majority of the representatives of the suborder Ensifera ( Ashwath and Aswathanarayana 1979 ; Hewitt 1979 ; Warchalowska-Sliwa 1980 ; Baccetti and White 1983 ; Bhunya and Das 1985 ; Lambort and Alvarez-Sarret 1985 ; Davenport 1986 ; Das 1989 ; Das and Das 1991 , 1992 ; Warchalowska-Sliwa et al 1997 ; Zefa 1999 ; Mesa and Zefa 2004 ; Ferreira and Cella 2006 ), it seems reasonable to accept that karyotype I (2n(♂) = 22+X0 with all autosomes acrocentric) is the pattern type for Anurogryllus sp. The karyotypes with lower diploid number and some metacentric autosomes probably originated by centric fusions and should be derived from the higher diploid number.…”

“…This order is divided into two suborders: Caelifera, with approximately 11,000 species, including the grasshoppers and the locusts, and Ensifera, which has around 9,000 species, including the crickets and the katydids ( Gwynne et al 1996 ). Though these two suborders have an almost equal number of described species, caeliferans have been more extensively studied from the cytogenetic viewpoint ( Hewitt 1979 ; Bhunya and Das 1985 ; Das and Das 1991 , 1992 ). This difference may be due, in part, to the lack of taxonomic identification of the ensiferan species.…”

“…The X0 sex chromosome system is the predominant type in this group; nevertheless, other simple or multiple systems, such as XY and X 1 X 2 Y, were also reported. As with the majority of orthopterans, the Gryllidae autosomes commonly exhibit the acrocentric morphology; unlike other orthopteran families, the X sex chromosome is metacentric ( Ashwath and Aswathanarayana 1979 ; Hewitt 1979 ; Warchalowska-Sliwa 1980 ; Baccetti and White 1983 ; Bhunya and Das 1985 ; Lamborot and Alvarez-Sarret 1985 ; Davenport 1986 ; Das 1989 ; Das and Das 1991 , 1992 ; Warchalowska-Sliwa et al 1997 ; Zefa 1999 ; Mesa and Zefa 2004 ; Ferreira and Cella 2006 ).…”