4倍体ハイイロヒョウタンゾウムシから単為的に生じた3倍体と4倍体の胚の染色体

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(1)Title. 4倍体ハイイロヒョウタンゾウムシから単為的に生じた3倍体と4倍体の胚の染色体. 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, 33(2): 67-71. Issue Date. 1983-03. URL. http://s-ir.sap.hokkyodai.ac.jp/dspace/handle/123456789/6399. Rights. Hokkaido University of Education.

(2) Journal of Hokkaido University of Education (Section II B) Vol. 33, No. 2 March, 1983. ^ja&t±"Nifi® (^2$|SB) ^33^ ^2^- Bgffi58^3^. ON THE CHROMOSOMES OF TRIPLOID AND TETRAPLOID EMBRYOS. PRODUCED BY A TETRAPLOID PARTHENOG-. ENETIC CATAPIONUS GRACILICORNIS ROELOFS FEMALE (CURCULIONIDAE COLEOPTERA). Yasushi TAKENOUCHI Biological Laboratory, Sapporo College, Hokkaido University of Education, Sapporo 064. ^ ^: 4^^^^ Pb 3^^>y'^^^^^^^6^^^^^ 3^^^ 4^<7)EO^fe^ »Mt^riNLi??^t»^a^. Abstract Upon checking the chromosomes of cleavage nuclei it was observed that both triploid and tetraploid embryos were produced by a single tetraploid parthenogenetic Catapionus gracilicornis female. On the basis of this fact a wide survey was carried out in the Oshima peninsula and, at last, a triploid Catapionus gracilicornis female was found for the fist time in the Shiriuchi district of Hokkaido. Catapionus gracilicornis Roelofs is one of the native Japanese species of curculionid weevil belonging to the subfamily Brachyderinae. The species has four races: pentaploid, tetraploid, triploid parthenogenetic ones as well as a diploid bisexual one. Both pentaploid and tetraploid races are distributed in the east-northern part of Japan-Hondo (Iwate, Akita, and most parts of. Aomori Prefectures except Mt. Shirakami-dake where the diploid bisexual race is distributed) in the ratio 50:50. The diploid bisexual race is mostly distributed in Niigata Prefecture, although, very recently a triploid parthenogenetic race has been found in Miomote together with the diploid bisexual race. On the other hand, only a tetraploid parthenogenetic race is distributed on Hokkaido and no other races have so far been obtained during my continuous and wide ranging chromosome survey of the last 30 years (Takenouchi, 1957 a, b, 1959, 1966, 1969, 1971,1976a, b, c, 1982). Although 60 parthenogenetic weevil species and races (6x, 5x, 4x,. (D.

(3) 68 Yasushi TAKENOUCHI. and 3x) have been known cytologically to include two diploid species (2n=2x=22), no actual evidence on the correlation between occurrences and relationships of these biotypes with different degrees of polyploidy has so far been reported. Accidentally, I have had a chance to find an interesting phenomenon that may solve a part of the problem mentioned above. This paper reports the details.. Materials and JMethods A single Catapionus gracilicornis Roelofs female was captured on a thistle in a bushy area at Sengen, Oshima peninsula, southern Hokkaido, on July 12, 1977. The insect was already laying eggs and was reared in a petri dish which was covered with a glass lid of the ordinary type. A piece of a fresh leaf of the same kind of thistle was given as food as usual (Takenouchi, 1957b, 1959). She laid eggs every day. Squash slides of eggs were raade according to Smith's method (1943) at various hours after oviposition due to room temperatures because the speed of cleavage division is evidently influenced by temperatures. In the early part of July 1978 I collected 14 C. gracilicornis females from Mt. Daisengendake,Sengen, Shiriuchi, and Fukushima-cho, Oshima peninsula, and their eggs were squashed as. usual to obtain their chromosome number, but the eggs of 2 females were squashed with a 20 % acetic gentian violet solution. Photomicrographs were taken with a Olympus PM-6 and drawings were made with the aid of a camera lucida.. Observations The insect laid 39 eggs on July 16 and 17, 1977. The chromosomes of all embryos were studied in their cleavage nuclei. Among them the chromosome number was clearly observed in 5 embryos: two had 44 chromosomes, one 43, another 33 and the remaining one 35 (Figs. 1-. 5). On the other hand, among 14 specimens collected in 1978, 10 showed exactly 44 chromosomes in their eggs (embryos), 3 showed 42, and one, 33. The last number was clearly observed in 9 cells of 3 embryos (Figs. 6-8).. Discussion. According to Suonalainen (1940a, b, 1954, 1969), Mikulska (1953, 1960) and Takenouchi (1969, 1971, 1972, 1976a, b,) the chromosome number in polyploid parthenogenetic weevils, whether in the oogonial and maturation metaphases of a specimen or a species, is not always an exact multiple of the basic number, 11 or 10, though most numerous numbers are, of course, exactly 66, 55, 44, 33, or 30. In C. gracilicornis the same situation has commonly been found. (Takenouchi, 1971). Therefore, the chromosome numbers, 43 and 35, obtained in this investiga-. (2).

(4) Triploid and Tetraploid Embryos Produced by a Tetraploid Female Weevil. 69. tion are of tetraploid and triploid, respectively. Accordingly, it is clear that the female weevil here studied produces both tetraploid and triploid progenies though the triploid adult females of this species have not yet been found in Hokkaido Island. The triploid race was very recently found however in Miomote, Niigata Prefecture, in Hokuriku district, Japan-Hondo (Takenouchi, 1982). Suomalainen (1940a, b, 1947) first found that in polyploid parthenogenetic weevils the. ^^^. ^ %'A\il) *0. ;»r^ -YT ..^ ••. Figs. 1—5. Metaphase chromosomes in early cleavage of embryos produced by a single tetraploid Catapionus gracilicornis. 1. and 2. Showing 44 chromosomes. 3. Showing 43 chromosomes. 4. Showing 35 chromosomes. 5. Showing 33 chromosomes. X 3,000. (3).

(5) 70. Yasushi TAKENOUCHI. Figs. 6—8. Metaphase chromosomes in early cleavage of three embryos produced by a single triploid female Catapionus gracilicornis; from squash slides stained with aceto-gentian violet, showing 33 chromosomes, respectively. X 3,000 unpaired chromosomes are ordinarily arranged on a single plate at metaphase of the matura-. tion division of the egg as in somatic mitosis, but they are sometimes irregularly arranged as if for a multiple, or on different metaphase plates in groups that contain exact multiples of n=11. For instance, in triploid Sciaphiltts asperatus Bonsd and Otiorrhynckus ligustici L. separations into two groups with the diploid (22) and haploid (11) numbers have been observed ; in tetraploid Otiorrhynchus dubhis Strom, distributions of the three types 33+11, 22+22, and 22 + 11+11; in 0. scaber L. two types, 33+11 and 22+11. The same phenomenon was found in triploid 0. sulcatus F. by Seller (1947). Accordingly, Suomalainen (1962) stated that "As the different chromosome plates of the same egg can be situated far apart from each other, it is conceivable that some plate, for instance, a haploid plate, could be cast off from the nucleus later formed by the other chromosome plates. This would lead to a decrease of the polyploidy by one degree." I am sure this is the reason why the C. gracilicornis female, here studied,. reproduced both tetraploid and triploid embryos, because my detailed cytological study on this species has revealed the occurrence of the bipartite metaphase plates in the maturation division : the one with 33 chromosomes and the other, 11 chromosomes (Takenouchi, 1971). This is the first report of actual evidence with regard to the occurrence of the parthenogenetic weevil race with a different degree of polyploidy. The real evidence for suomalainen's hypothesis was obtained in 1978. Fourteen C.. gracilicornis females were investigated and among them 13 females with 42 or 44 chromosomes were undoubtedly members of the tetraploid race ; the remaining specimen, with 33 chromosomes, is no doubt the fist triploid parthenogenetic weevil to be found in Hokkaido.. (4).

(6) Triploid and Tetraploid Embryos Produced by a Tetraploid Female Weevil 71. Acknowledgement The author is greatly indebted to Professor Dr. Esko Suomalainen, Helsinki University, Finland, for his invaluable advice.. References. Mikulska, I. 1935 The chromosomes of the parthenogenetic and thelytokian weevil Ensomiis ovulum Germ. (Curculionidae, Coleoptera). Bull. Acad. Pol. Sci. Lettr., Ser. B II, 1951: 293-307.. Mikulska, I. 1960 New data to the cytology of the parthenogenetic weevils of the genus Otiorrhynchns Germ. (Curculionidae, Coleoptera) from Poland. Cytologia (Tokyo), 25: 322—333. Seiler, J. 1947 Die Zytologie eines parthenogenetischen Riisselkafers, Otiorrhynchus sulcatns F. Chromosoma, 3: 88-109. Smith, S. G. 1943 Techniques for the study of insect chromosomes. Can. Entomol. 75: 21—34.. Suomalainen, E. 1940a Polyploidy in parthenogenetic Curculionidae. Hereditas (Lund), 26: 51—64. Suomalainen, E. 1940b Beitrage zur Zytologie der parthenogenetischen Insekten. I. Coleoptera. Ann. Acad. Sci. Fenn., A, 54: 7: 1-144.. Suomalainen, E. 1947 Parthenogenese und Polyploidie bei Riisselkafern (Curculionidae). Hereditas (Lund), 33: 425-456. Suomalainen, E. 1962 Significance of parthenogenesis in the evolution of insect. Ann. Rev. Entom., 7; 349— 366. Suomalainen, E. 1969 Evolution in parthenogenetic Curculionidae. in Evol. Biol. Vol. 3 (T. Dobzhansky, M. Hecht. W. Steere, eds.) pp. 261—296. Appleton-Century-Crofts, New York. Takenouchi, Y. 1957a Polyploidy in some parthenogenetic weevils. Annot. Zool. Japan. 30: 38—41 Takenouchi, Y. 1957b On a parthenogenetic weevil, Catapionns gracilicornis Roelofs. Zool. Mag. 66: 198—205. Takenouchi, Y. 1959 Some oecological observations of three species of curculionid weevils, with special reference to parthenogenetic reproduction. J. Hokkaido Gakugei Univ. Ser. 2, 10: 297—339.. Takenouchi, Y. 1966 Tetraploid and pentaploid races of the Japanese parthenogenetic weevil, Catapiomis gmcilicornis Roelofs (Curculionidae, Coleoptera). Annot. Zool. Japon. 39: 47—54. Takenouchi, Y. 1969 A further study on the chromosomes of the parthenogenetic weevil, Listroderes costiro-. stris Schonherr, from Japan. Cytologia (Tokyo), 34: 360—368. Takenouchi, Y. 1971 A bisexual race of the reportedly parthenogenetic Japanese weevil Catapionus gracilicornis Roelofs (Coleoptera: Curculionidae). J. Hokkaido Univ. Educ. Ser. IIB, 22: 1—17.. Takenouchi, Y. 1976a A study on the chromosomal dimorphism in Catapionus gracilicornis Roelofs (Curculionidae: Coleoptera). Jpn. J. Genet. 51: 279-283.. Takenouchi, Y. 1976b A study of polyploidy in races of Japanese weevils (Coleoptera: Curculionidae). Genetica, 46: 327-334.. Takenouchi, Y. 1976c A hexaploid parthenogenetic weevil Blosyms japonicns Sharp with 68 chromosomes (Coleoptera: Curculionidae). Chrom. Inform. Serv. 19: 24—26.. Takenouchi, Y. 1982 A triploid race of the reportedly parthenogenetic Japanese weevil Catapionus gracilicornis Roelofs (Coleoptera: Curculionidae). Jpn. J. Genet. 57: 185—187. Addendum: This paper was accomplished on August 31, 1978.. 5).

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