INTRODUCTION

Mecopoda elongata (L.) is one of the morewidely distributed katydids. The area of thisspecies includes the greater part of the Orien-tal region and Northern part of the Aus-tralasian one. At present two subspecies arerecognized in the species as a consequence thatmany species, subspecies, and variations havebeen synonymized as M. elongata (OTTE 1997).These invalid taxa different only slightly inmorphology. However, it is necessary to exam-

ine the exact taxonomic position of differentpopulations of this species because severaltypes of song are observed in among them. Thepresent authors used cytogenetic analysis ofthree song populations of M. elongata fromJapan and Malaysia for the first step in revisingthis species.

There are very few cytogenetic data con-cerning the Mecopoda. At first HAREYAMA(1932) reported a diploid number of 27 in themale of M. elongata nipponensis from Japan.Later, ASANA et al. (1938) described a kary-otype of the M. elongata from Northern Indiawith 2n = 27 consisting of one pair submeta-centric, one pair subacrocentric, 11 pairs of

CARYOLOGIA Vol. 57, no. 1: 25-29, 2004

Karyotype and C-banding patterns of the katydidMecopoda elongata (L.) (Orthoptera, Tettigoniidae,Mecopodinae) from Amami Is. (Japan) and Borneo(Malaysia)A.G. BUGROV1, E. WARCHALOWSKA-SLIWA2, *, ITO G.3, A. TCHERNYKH4 and MARYATI M.51 Novosibirsk State University, 630090 Novosibirsk, Russia and Institute for Systematics and Ecology of Animals, Siberian

Branch of Russian Academy of Sciences, 630091 Novosibirsk, Russia.2 Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, 31-016 Krakow, Slawkowska 17, Poland.3 Systematic Entomology, Department of Ecology and Systematics, Graduate School of Agriculture, Hokkaido University,

Kita-9, Nishi-9, Kita-ku, Sapporo 060-8589, Japan.4 Juras Vejs, Riga, 1045, Latvia.5 Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Locked bag 2073, 88999 Kota Kinabalu, Sabah,

Malaysia.

Abstract - Two types of the karyomorphs in the katydid Mecopoda elongata (L.) fromBorneo (Malaysia) and Amami Is. (Japan) were found. The chromosomal comple-ment of M. elongata from Amami Is. and one karyomorph from Borneo (KotaKinabalu – song 1) consists of 28 autosomes plus the X in the male (2n=29). In twolong pairs, pair L1 is metacentric, whereas pair L2 is subacrocentric. Other autosomesare meta or submetacentric. The size and shape of the X chromosome is similar tothe L1 pair. “Kota Kinabalu - song-2” karyomorph has the same chromosome num-ber as “KK song-1” and “Amami”. However, in ”KK song-2” the autosomes belong-ing to L2 pair are metacentric. The size of these chromosomes is approximately sim-ilar to the L1 pair and the X chromosome. The discrete chromosome differentiationin M. elongata suggest that this species consists of several biological species. In M.elongata from Borneo, the assumption of a belonging of two groups of the kary-omorphs to different species proves to be true also in differences in crepitating.

Key words: karyotypes, C-banding, evolution, Orthoptera.

* Corresponding author: e-mail: warchalowska@isez.pan.krakow.pl

acrocentric chromosomes, and the metacentricX-chromosome. Relatively recently ASWATHA-NARAYANA and ASHWATH (1994) described thekaryotypes of two species belonging to thegenus Mecopoda and reported the C-bandingpattern of one of those species named asMecopoda sp. They confirmed the possesing ofa 27 chromosome form in Mecopoda on the ma-terial from South West India. However, theydescribed the 29 chromosome karyotype in M.

elongata from the same site, in the vicinities ofMysore city, which differ from the karyotype ofMecopoda sp. in chromosome number andmorphology of the second autosome pair. Un-fortunately, they did not mention any morpho-logical or crepitating differences between M.elongata and Mecopoda sp.

The level of diversity of chromosome com-plements may suggest that karyotypic diversifi-cation is one of the features of the speciation in

26 BUGROV, WARCHALOWSKA-SLIWA, ITO, TCHERNYKH and MARYATI

Fig. 1a-d. – Mecopoda elongata of individual from Amami Is.: (a) spermatogonial metaphase; (b) male karyotype – in L2 C-bandsheteromorphic in size; (c) metaphase I; (d) spermatogonial metaphase – in L2 C-bands homomorphic on size.

this species. This suggestion was the reason forstudying the karyotypes of M. elongata fromnew localities. In the present paper two kary-omorphs of M. elongata from Japan andMalaysia are reported.

MATERIALS AND METHODS

In early September 2000, 10 male nymphs and 2adult males were collected in Amami Is., Ryukyu Arch-ipelago, Japan (“Amami”). In late November 2001, 8adult males were collected in Kota Kinabalu, Sabah,Malaysia on a song at night. In Kota Kinabalu two dis-tinct types of song were observed (“KK song-1” and“KK song-2”). “Song-1” is a continuous monotonouscrepitating. “Song-2” consists of separate portions ofthe crepitating. Both songs differed from the song of“Amami”. But the continuous crepitating of “Amami”that follows after several short crepitating is almost thesame as “KK song-1”. The males were placed in twoseparate plastic insect boxes according to their songs.

The males and male nymphs were injected with0.1% colchicine for 1.5 - 2.0 hours. The testes were

excised, incubated in hypotonic solution (0.9% sodi-um citrate), fixed in ethanol:glacial acetic acid (3:1),and kept in 70% ethanol. Air dried preparations weremade by squashing the testicles in 45% acetic acid andfreezing them in dry ice. They were then stained withC-banding by treatment with 0.2 N HCL for 15 - 20min, immersed in a saturated solution of Ba(OH)2 at61°C for 3-5 min, rinsed in water, immersed in 2xSSCat 61°C for 60 min, rinsed, air-dried, and stained with2% Giemsa.

RESULTS

The chromosomal complement of “Amami”consists of 28 autosomes plus the X in the male(2n=29). Autosomes can be divided into threesize groups: 2 large (L1 and L2), 12 medium, andsmall (M3 – S14) (Fig. 1). In two long pairs, pairL1 is metacentric, whereas pair L2 is subacro-centric. Other autosomes are meta, submeta- orsubacrocentric, gradually decreasing in size.The size of submetacentric X chromosome isapproximately similar to the L1 pair (Fig. 1a,b).

KARYOTYPE AND C-BANDING IN MECOPODA ELONGATA 27

Fig. 2a-c. – Mecopoda elongata of individual from Borneo: (a) male karyotype from individual of “KK song-2”, pair L2 is meta-centric ; (b) metaphase I and (c) metaphase II with two metacentric bivalents L1 and L2 (arrows).

The paracentromeric C-blocks occur in allchromosomes of the complement, their sizevarying among autosomes. The first pair of theautosomes has a thick centromeric C-blockwith an interstitial one near centromeric posi-tion, and telomeric C-blocks in both armswhich vary in size. The second pair has a thickparacentromeric C-band, heterochromaticshort arms, and telomeric C-band in the longarm (Fig. 1a-d). Sometimes both C-blocks wereheteromorphic in size (Fig. 1a,b). The auto-somes belonging to the M3 and S4 pairs haveparacentromeric C-bands and telomeric onesin long and short arms. Other autosomes arecharacterised by the presence of paracen-tromeric C-bands and telomeric ones in someof them (Fig. 1b). Short arms in five small pairs,(S5, S6, S7, S8, S9), are heterochromatic. In oth-er small pairs both the arms are euchromatic.The X chromosome has a thick paracen-tromeric C-block; sometimes it is clearly seen,such as a double, interstitial one near the telom-eric end in the shorter arm, and interstitial andtelomeric ones in the longer arm (Fig. 1a-d).

The chromosome complement of “KKsong-1” has a karyotype very similar to “Ama-mi” as on morphology of the chromosomes,and on localities of the C-banding regions. Un-like those from the “Amami” population, thetelomeric C-blocks in the X chromosome of“KK song-1” population show a sporadicallyvariability in size .

“KK song-2” has the same chromosomenumber as “KK song-1” and “Amami”. How-ever, in ”KK song-2” the autosomes belongingto L2 pair are metacentric (Fig. 2a-c). The sizeof these chromosomes is approximately similarto the L1 pair and the X chromosome. The re-sults showed some differences in C-bandingpatterns in the two song types. The secondmetacentric pair, such as L1, is characterised bythick-double paracentromeric C-blocks. Addi-tionally, in third medium size pair (M3) of au-tosomes the euchromatic region in short armand telomeric C-blocks in long arm were ab-sent (Fig. 2a).

DISCUSSION

There is great interest among evolutionarybiologists in the role of chromosome changes inspeciation. The discussion on chromosome spe-

ciation is connected with the stasipatric modelof speciation (WHITE 1968, 1974). One of theimportant features of the stasipatric model isthat certain chromosomal changes play a keyrole in the initial stages of speciation (WHITE1968). The conception of chromosomal speci-ation stimulated a development of the evolutioncytogenetic investigation in different groups ofanimals. As to Orthopteran insects, more laterresearches showed that karyotipic differencesare only a weakly selected marker for more fun-damental changes in genome (SHAW andWILKINSON 1980; BARTON and HEWITT 1981).Nevertheless, the discussions about the role ofchromosome changes in evolution have contin-ued to the present (KING 1993). In spite of thediscussion concerning the concept of chromo-some speciation in Orthoptera there are veryfew models connected with this problem. Prob-ably, the Mecopoda elongata (L.) will becomeone more model in this respect.

In the area of distribution in South andSouth East Asia M. elongata presented somechromosomal races. One karyomorph fromSouth India (ASWATHANARAYANA and ASH-WATH 1994), Amami Is., Japan (“Amami”, pre-sent paper), and Borneo (“KK song-1”, presentpaper) have common chromosome number(2n=29). “KK song-1” and “Amami” differfrom the Indian 29 chromosome M. elongata inthe presence of a short second arm in L2 auto-some. At the same time, “KK song-1” and“Amami” have identical karyotypes. C-band-ing patterns in chromosomes of Japanese andBornean 29 chromosomal races also are verysimilar. Another Mecopoda species from Indianamed as Mecopoda sp. has a different type ofchromosome complement consisting of 26 au-tosomes plus the X in a male (ASWATHA-NARAYANA and ASHWATH 1994). The first pairof autosomes is submetacentric with a minorcentromeric C-block, minor telomeric C-blockin the long arm, and a thick telomeric one inthe short arm. The X-chromosome resemblesthe first chromosome pair except for the pres-ence of the interstitial band near the cen-tromere and the absence of the small telomer-ic C-band in the long arm. The second pair ofthe autosome is subacrocentric with polymor-phic in the size of centromeric C-block. Thereare two types of the small chromosome pairs inMecopoda sp. Six pairs of them are meta- andsubmetacentric, while other pairs are acrocen-

28 BUGROV, WARCHALOWSKA-SLIWA, ITO, TCHERNYKH and MARYATI

tric. In common, C-banding patterns of thiskaryomorph are similar to those of M. elongatafrom Amami and from Borneo.

“KK song-2” has a more peculiar structureof karyotype in the presence of a large secondmetacentric pair between the researched pop-ulations of M. elongata. The karyotype of suchmorphology was not previously described in M.elongata.

The high level of chromosome differentia-tion among populations in M. elongata arguethe suggestion that this species consists of sev-eral biological species, since karyotypic diver-sification often leads to reproductive isolationowing to hybrid incompatibility (WHITE et al.1967; MRONGOVIUS 1979; BARTON and HEWITT1981). As to M. elongata from Borneo, the as-sumption of the belonging of two groups of thekaryomorphs to different species proves to betrue also in differences in crepitating.

Acknowledgements – The first author wishes tothank Dr. Yoshiyuki Maeda for his kind help in fieldworks in Amami Is.

REFERENCES

ASANA J.J., MAKINO S., NIIYAMA H., 1938 – A chro-mosomal survey of some Indian Insects. I. Mor-phology of the chromosomes in eight species of theLocustidae. J. Fac. Sci. Hokkaido Univ., Ser. 6:211-234.

ASWATHANARAYANA N.V., ASHWATH S.K., 1994 –Karyotypes of two Indian Mecopodinae (Or-thoptera – Tettigoniidae). Cytologia, 59: 285-287.

BARTON N.H., HEWITT G.M., 1981 – The geneticbasis of hybrid inviability in the grasshopperPodisma pedestris. Heredity, 47: 367-383.

HAREYAMA S., 1932 – On the chromosomes of someinsects belonging to Locustidae. Zool. Mag.(Japan), 44: 83-84.

KING M., 1993 – Species Evolution: The Role ofChromosome Change. Cambridge UniversityPress, Cambridge.

MRONGOVIOUS M.J., 1979 – Cytogenetics of the hy-brids of three members of the grasshopper genusVandiemenella (Orthoptera: Eumastacidae: Mora-binae). Chromosoma, 71: 81-107.

OTTE D., 1997 – Tettigonioidea. Orthoptera Speciesfile, n. 7. Philadelphia.

SHAW D.D., WILKINSON P., 1980 – Chromosome dif-ferentiation, hybrid breakdown and the mainte-nance of a narrow hybrid zone in Caledia captiva.Chromosoma, 80: 1-31.

WHITE M.J.D., 1968 – Models of Speciation. Sci-ence, 159: 1065-1070.

–, 1974 – Speciation in the Australian Morabinegrasshoppers. The cytogenetic evidence. In: WhiteM.J.D. (Ed.) “Genetic Mechanisms of Specia-tion in Insects”, pp. 57-68. Sydney, Australia andNew Zealand.

WHITE M.J.D., BLACKITH R.E., BLACKITH R.M.,CHENEY J., 1967 – Cytogenetics of the viaticagroup of morabine grasshoppers. I. The “coastal”species. Aust. J. Zool., 15: 263-302.

Received April 29, 2003; accepted July 12, 2003

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