単為生殖型マルカククチゾウの隔離されている2倍体 : 両性生殖種族の染色体研究

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(1)Title. 単為生殖型マルカククチゾウの隔離されている2倍体 : 両性生殖種族の染色体研究. Author(s). 竹内, 恭. Citation. 北海道教育大学紀要. 第二部. B, 生物学,地学,農学編, 26(2): 51-54. Issue Date. 1976-02. URL. http://s-ir.sap.hokkyodai.ac.jp/dspace/handle/123456789/6338. Rights. Hokkaido University of Education.

(2) Journal of Hokkaido University of Education (Section II B) Vol. 26, No. 2, February 1976. -?ig»t-*<N59? (^ 2 % B) ® 26 ^ % 2 -^ Bgffi 51 ^ 2 H. Chromosome Study of an Isolated Diploid Bisexual Race of the Reportedly Parthenogenetic Japanese Weevil Blosyms japonicus Sharp (Coleoptera : Curculionidae). Yasushi TAKENOUCHI Biological Laboratory, Sapporo College, Hokkaido University of Education. 064 Sapporo. m^^^y^-f-y'^^M^ir^^^ 2^?. m^mmm^ww^ It n ^. ^•im^.if±^MW^-'^^. As I reported at the Fourth International Chromosome Conference in Jerusalem in 1972, Blosyrus japonicus Sharp has four races : one 2?-?,,and bisexual (Esashi, Hakodate, and Wannai and. Himenuma, Rishiri Isl.) and three parthenogenetic 4x (Bihoro Pass, Abashiri), 5x (Bihoro Pass, Abashiri, Jflgoshima Park, Sappro), and the highest degree of polyploidy in weevils, 6x (Oshidomari, Rishiri Isl.) (Takenouchi, 1970a, 1972b, 1973, 1975). This time I have had a chance to investigate the chromosomes of this species collected from Oshima-kojima Island and the results are described in this paper.. Materials and Methods A total of 13 specimens of Blosyms japoniciis Sharp were collected in Oshima-kojima in mid-May of 1973. Dissection showed that among them 11 were males and 2 females. Squash preparations of gonads were made from all males and females. Before squashing, both males and females were pretreated with colchicine and then stained. in methyl green-basic fuchsin (Smith and Takenouchi, 1969). And also ovaries and mature eggs were fixed in Allen-Bouin's solution modified according to Momma. (1954) and embedded in paraffin. Sections were cut seven microns thick and stained in Heidenhain's iron-haematoxylin. Photomicrographs were taken by an Olympus PM-6 and enlarged to a magnification ca. X 3,600.. 1). 0.. Fig. 1. Map of southern Hokkaido and. Kojima (Oshima-kojima)..

(3) 52. Yasushi TAKENOUCH1. Observations Two males provided excellent spermatogonial metaphases and three males first metaphases. On the other hand, females provided nothing because of scanty materials. Spermatogonial metaphases contain 22 chromosomes (Figs. 1 and 2), of which six are larger. Size seriation of the smaller elements is gradual, except for a tiny, dot-like body which is out-. standing in the complement; clearly it is the y. The X is undetectable at this stage. Most if not all chromosomes are meta- or submetacentric. There are 11 bivalents in the first metaphase (Fig. 3). The smallest, parachute shaped bivalent, is the sex pair as most of other bisexual weevil species. The size seriation of the autosomal bivalents is quite gradual.. r':. ^A^'$$BIKiB5 f.. Figs. 2-5. Chromosomes of Blosyrns japonicus from Kojima. 2 and 3. Spgs., 22 chromosomes. 4 and 5. Mis, 10 + Xy^.. Discussion According to Smith (personal communication) the chromosome survey of bisexual curculionid weevil species, omitting parthenogenetic taxa, has so far been extended to about 340. On the other hand fifty-four parthenogenetic species and races are known in five allied subfamilies of the Curculionidae, i. e., Otiorrhychinae, Brachyderinae, Eremninae, Leptopinae, and Cylindrorrhyninae. In the weevil species parthenogenesis is usually connected with polyploidy and out of. fifty-four species and races known cytologically 52 are polyploids : 30 triploids, 15 tetraploids, 5 pentaploids and two recently reported hexaploids by Takenouchi ; the remaining two are diploids (2x = 2n) (Suomalainen, 1940a,b, 1947, 1954, 1955, 1966 ; Mikulska, 1960 ; Seller, 1947 ; Takeno-. (2).

(4) Isolated Diploid Bisexual Race of a Weevil 53. uchi, 1957, 1964, 1965, 1966, 1968, 1969a,b, 1970a-c, 1972a,b, 1973, 1974, 1975). Among them the basic chromosome number of the 3 triploid species is 10, all of the others are eleven. As pointed. out by Suomalainen, in many species it is typical that races with different degrees of polyploidy coexist and, further, that some of them have a diploid bisexual race. A Japanese weevil species,. Blosyrus japonicus, is the first hexaploid one and further investigations showed that it had tetraand penta-ploid races as well as a diploid bisexual race in Hokkaido main island and haxaploid and diploid bisexual races coexist in Rishiri Island. Although they had distinct distributions so far, a recent investigation showed that in a certain place of Hokkaido both polyploid parthenogenetic specimens and diploid bisexual specimens 'coexist and they mate in there (Takenouchi,. unpublished). The small island named Kojima (Oshima-kojima) with an area of 1 km2 is situated in the Japan Sea, about 30 km off Cape Shirakami in southwestern Hokkaido. The island has a flat top covered with latifoliate trees and is surrounded by steep cliffs ( Yoshii, 1966). This investigation revealed that 11 Blosyrus japonicus males from the island are diploid (2% ==22, n = 10 + Xyp). Although females did not provide any division they were smaller than polyploid parthenogenetic females, the fact clearly showed that they were a diploid bisexual race ;Takenouchi, 1972b, 1975). The result indicates that in Kojima there is a completely isolated diploid bisexual race of this species from other polyploid parthenogenetic races. From the viewpoint of geological development, Kojima Island and Hokkaido Island as well as other islands separately erupted at Early Holocene after Wurm Ice Age (Minato, et all, 1965). I suppose this is the main reason why Kojima has only an isolated diploid bisexual race of Blosyrus japoniciis :hough its geographical constitution is almost similar to that of Hokkaido Island. Summary The chromosomes of a Japanese weevil species, Blosyrus japonicus, from a small island, Ko-. jima (Oshima- kojima), was studied. The specimens investigated are of a diploid bisexual race only though the species has three parthenogenetic •••••• 4x, 5x and 6x as well as a diploid bis-. exual race (2-n) in Hokkaido Island and 2n and 6x races in Rishiri Island. Acknowledgments I express my sincere gratitude to Dr. K. Morimoto, Kyushu Branch, Government Forest Experiment Station, Kurokami, Kumamoto, for identification of species and to Prof. H. Asai,. Geological Laboratory, Sapporo College, Hokkaido University of Education, for invaluable advice. Messrs. T. Shiitsu and H. Watabe, and Miss A. Suzuki and R. Kamada helped collect the material. References Mikulska, I., 1960 . New data to the cytology of the parthenogenetic weevils of the genus Ottorrhynchiis Germ. (Curculionidae, Coleoptera) from Poland. Cytologia 25 : 322-333. Minato, M., M. Gorai, and M. Hunahashi, 1965 The geologic development of the Japanese islands. Tsuluji Shokan Co. LTD. Tokyo. Momma, E., 1954 Drosophita survey of Hokkaido. II. Chromosomes of seven species. J. Fac. Sci. Hokkaido Univ., Ser. VI. Zool. 12 : 200-208. Seiler, J., 1947 Die Zytologie eines parthenogenetischen Russelkafers, Otion-hynchns snl.catns F. Chromosoma 3 : 88-109.. (3).

(5) 54 Yasushi TAKENOUCHI Smith, S. G., and Y. Takenouchi, 1969 Chromosomal polymorphism in Pissodes weevils : Further on incompatibility in Pi'ssodes terminai.is. Can. J. Genet. Cytol. 11 : 761-782. Suomalainen, E., 1940a Polyploidy in parthenogenetic Curculionidae. Hereditas 26 : 21-34. Suomalainen, E., 1940b Beitrage zur Zytologie der parthenogenetischen Insekten. Ann. Acad. Sci. Fenn. 53 : 1-145.. Suomajainen, E., 1947 Parthenogenese und Polyploidie bei Russelkafern (Curculionidae). Hereditas 26 : 425 -456. Suomalainen, E., 1954 Zur Zytologie der parthenogenetischen Curculioniden der Schweiz. Chromosoma 6 : 627-655. Suomalainen, E., 1955 A further instance of geographical parthenogenesis and polyploidy in the weevils, Curculionidae. Arch. Soc. 'Vanamo', 9 Suppl. : 350-354. Suomalainen, E., 1966 The first known case of polyploidy in a parthenogenetic curculionid native of America.. Hereditas 56 : 213-216. Takenouchi, Y., 1957 Polyploidy in some parthenogenetic weevils (A preliminary note). Annot. Zool. Japan. 30 : 38-41. Takenouchi, Y., 1964 A preliminary note on the chromosomes of 4 parthenogenetic weevils (Brachyrhin inae) in Canada. Jap. J. Genet. 37 : 74-79. Takenouchi, Y., 1965 Chromosome survey in thirty-four species of bisexual and parthenogenetic weevils of Canada. Can. J. Genet. Cytol. 7 : 663-687. Takenouchi, Y., 1966 Tetraploid and pentaploid races of the Japanese parthenogenetic weevil, Catapionus gracilicornis Roelofs (Curculionidae, Coleoptera). Annot. Zool. Japan. 39 : 47-54. Takenouchi, Y., 1968 A chromosome study on bisexual and parthenogenetic races of Scepticns insularis Roelofs (Curculionidae, Coleoptera). Can. J. Genet. Cytol. 10 : 945-990. Takenouchi, Y., 1969a A further study on the chromosomes of the parthenogenetic weevil, Listroderes costi/'os//'/s Schonherr, from Japan. Cytologia 34 : 360-368. Takenouchi, Y., 1969b On the chromosomes of the parthenogenetic weevil, Listroderes costirostris Schonherr, from Nagasaki Prefecture. Chrom. Inform. Serv. 10 : 3-4. Takenouchi, Y., 1970a Three further studies of the chromosomes of Japanese weevils (Coleoptera : Curculionidae). Can. J. Genet. Cytol. 12 : 273-277. Takenouchi, Y., 1970b A further chromosome study in bisexual and parthenogenetic races of the weevil, Catapionus gracilicornis Roelofs (Curculionidae : Coleoptera). Jap. J. Genet. 45 : 457-466. Takenouchi, Y., 1970c A bisexual race of the reportedly parthenogenetic Japanese weevil Cafapionus gracilicornis Roelofs (Coleoptera : Curculionidae). J. Hokkaido Univ. Educ. II B 22 : 1-17. Takenouchi, Y., 1972a A chromosome study of a new polyploid parthenogenetic weevil, Myllocerns nipponicus. Zumpt (Coleoptera : Curculionidae). KontyQ 40 : 121-123. Takenouchi, Y., 1972b A chromosome study on two hexaploid parthenogenetic weevils (Coleoptera : Curculionidae). Lecture in IVth Intern. Chrom. Conf. at Jerusalem. Takenouchi, Y., 1973 Polyploid races in two species of weevils. Chromosomes Today 4 : 432. Takenouchi, Y., 1974 A chromosome study on two new Japanese polyploid parthenogenetic weevils (Coleoptera : Curculionidae). Abstract in Vth Intern. Chrom. Conf. at Leiden. Chromosomes Today 5 : 353-360. Takenouchi, Y., 1975 A chromosome study on two hexaploid parthenogenetic weevils (Coleoptera : Curculionidae). Genetica 46 : (in press). Yoshii, M., 1966 Oshimakojima. Explanatory text of the geological Map of Japan. Scale 1 : 50,000. Geological Survey of Japan.. (4).

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