© 2012 The Japan Mendel Society Cytologia 77(3): 343–346

Karyotype Analysis of alacris alacris Serville (Insecta: : )

Yogesh Jangonda Koli1, Dilip Laxman Bharmal2, Aruna A. Kanase1 and Ganesh Parsharam Bhawane1*

1 Department of Zoology, Shivaji University, Kolhapur 416 004. MS, India 2 Shri. Panchamkhemraj Mahavidyalaya Savantvadi 416 510. MS, India

Received May 14, 2012; accepted May 28, 2012

Summary Chromosome and detailed karyotype information (number, shape, relative length, arm ratio, centromeric index) are described for E. alacris alacris of Chandoli National Park, India, be- longing to the subfamily . The diploid number of the chromosome was found to be 2n=23 with all metacentric pairs. The X chromosome is metacentric.

Key words Orthoptera, Karyotype, Eyprepocnemis, Chandoli National Park.

Orthoptera has been considered a classical material for karyological investigation. The size and number of their chromosomes are such that both qualitative and quantitative studies on chro- mosomal anomalies can be detected (Turkoglu and Koca 2002). The karyotype is found to have a cytotaxonomic value. The acridoid group is known for its karyotype uniformity and conservatism (Aswathanarayana and Ashwath 2006). The genus Eyprepocnemis belongs to the subfamily Eyprepocnemidinae of the family Acrididae, and comprises around 6 genera distributed in India (Shishodia et al. 2010). Studies on the chromosomes of attracted the attention of many researchers in the twentienth cen- tury. The majority of these researchers simply mentioned the diploid chromosome number without giving further details of their karyotype. Moreover, karyotypic analysis have been reported for only 117 in India between 1928 and 2000 (Singh 2002). In the present paper, the identification was carried out using the Kirby (1914) method, as cor- rected according to the revision of Mondal et al. (2007). Considering the lack of cytogenetic studies in grasshoppers from Indian fauna using techniques of standard and differential staining, the aim of this work was to determine the karyotype characteristics and the chromosome number.

Materials and methods

Adults and nymphs were collected in an area of vegetation located in Chandoli National Park, Maharashtra, India. The males were injected with 0.1–0.2 ml of 0.5% colchicines. After 1.5–3 h the testes were fixed in an aceto–methanol mixture (1 : 3). Tissue was then minced gently in 50% acetic acid to pre- pare a cell suspension. Drops of the cell suspension were placed on heated clean glass slides. The cells left on the slide were dried and then stained for 20 min in 2% aceto-orcein. This method fol- lows that slightly modified by Kacker et al. (1986). The preparations were examined under a light microscope with 100× magnification and the

* Corresponding author, e-mail: [email protected] DOI: 10.1508/cytologia.77.343 344 Y. J. Koli et al. Cytologia 77(3)

Fig. 1. 1. Adult male of Eyprepocnemis alacris alacris, 2. Gonial metaphase with normal complement, 3. Diakinesis, 4. Metaphase 1, 5. Male Karyotype, 6. Idiogram of haploid chromosomes of E alar- cris alacris. methaphasic miotic plates (10 plates) for each male individual with clear and well distributed chro- mosomes were photographed. Chromosomes were classified according to Levan et al. (1964).

Results and discussion

The karyotype of Eyprepocnemis alacris alacris is 2n=22+XO and 2n=22+XX in representa- tive somatic metaphase. The chromosomes and ideograms are shown in Fig. 1, and also provided as supplementary material. Based on the centromeric position (Table 1), the somatic chromosome complement can be broadly classified into 3 distinct groups: i) 3 long (1–3), ii) 6 medium (4–9) and ii) 2 short (10–11). All pairs are in the metacentric position. The X chromosome was always easily identified by virtue of its large size and metacentric morphology. The total length of the 11+X chro- mosomes is 68.56 µm. The longest chromosome is the X chromosome and its length is 11.32 µm and the smallest chromosome is 1.98 µm in length. Cytogenetic studies on Orthoptera have revealed a high diversity of examples of intra and in- 2012 Karyotype analysis of Eyprepocnemis (Insecta: Orthoptera: Acrididae) 345

Table 1. Morphometric characteristics of the chromosomes of Eyprepocnemis alacris alacris.

Chromosome Long arm (l) Short arm (s) Total length ‘d’ Value ‘r’ Value ‘i’ Value Centromeric No. μm μm C=l+s l-s l/s s/c×100 position

1 5.71±0.88 4.92±0.67 10.63±1.55 0.97 1.16 46.3 m 2 4.55±0.88 3.71±0.47 3.27±1.28 0.84 1.23 44.9 m 3 3.76±0.52 3.47±0.26 7.24±0.78 0.29 1.08 48.0 m 4 3.81±0.44 3.16±0.23 6.97±0.67 0.65 1.20 45.34 m 5 3.59±0.47 2.82±0.37 6.42±0.83 0.77 1.27 43.92 m 6 3.02±0.30 2.60±0.41 5.61±0.71 0.42 1.16 46.3 m 7 2.71±0.15 2.34±0.23 5.05±0.39 0.37 1.16 46.3 m 8 2.29±0.24 2.00±0.21 4.29±0.45 0.29 1.14 46.6 m 9 1.72±0.12 1.42±0.07 3.14±0.19 0.30 1.21 45.2 m 10 1.40±0.14 1.24±0.13 2.64±0.27 0.16 1.13 46.9 m 11 1.03±0.06 0.95±0.09 1.98±0.15 0.08 1.08 47.9 m X 5.93±0.36 5.39±0.71 11.32±1.07 0.54 1.10 47.6 m

terspecific karyotype variation in genera. This variation is the result of chromosomal rearrangement such as translocation and centric fusion which here mainly involves the autosomes and occasionally the sex chromosomes. In the present study, the original chromosome analysis and preparation of idiograms of E. alacrs alacris were undertaken. The chromosome structure may be a useful aid for the study of spe- cies relationships and the types of chromosome changes which have occurred during the evolution- ary development of the genus, while statistical analyses were undertaken on the length of chromo- somes and portions of arms. In the genus Eyprepocnemis, the chromosome number is known for Eyprepocnemis roseus, Eyprepocnemis lieber and . Cabrero et. al (1997) reported the geographical distribution of the B-chromosome in the Eyprepocnemis plorans along a river basin. They observed that Albacete Province (Southern Spain) harboured an Eyprepocnemis plorans population that lacks the B-chromosome, because of geo- graphical barriers that have impeded the invasion by Eyprepocnemis plorans individuals carrying the B-chromosome of the coastal population. Chatterjee (1958) reported similar results in relation to chromosome numbers and sex determination in Eyprepocnemis sp. Chatterjee (1970) also re- vealed similar results in Eyprepocnemis roseus, indicating that the short horned grasshoppers of different regions display cytogenetic uniformity regarding chromosome number and sex-determin- ing mechanism. During the present investigation, the chromosomes were found to be metacentric in nature.

Acknowledgements

The authors are thankful to the Head, Department of Zoology, Shivaji University, Kolhapur, for providing laboratory facilities. We are thankful to Dr. S. R. Yadav, Kumar Vinod. C. Gosavi and Manoj Lekhak, Department of Botany, Shivaji University, Kolhapur for providing laboratory facilities and for constant encouragement during this work. This work was supported by grants from the Department of Science and Technology (DST) New Delhi.

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