ヒメカメノコテントウの染色体

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(1)Title. ヒメカメノコテントウの染色体. 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, 30(1): 1-2. Issue Date. 1979-09. URL. http://s-ir.sap.hokkyodai.ac.jp/dspace/handle/123456789/6364. Rights. Hokkaido University of Education.

(2) Journal of Hokkaido University of Education (Section 11 B) Vol. 30, No. 1 September, 1979. ^?Sit^fl:±^5S (H2^B) ^30^ ^1-?- BgfD54^9^. A Chromosome Study on a Lady-bird Beetle, Propylea Japonica. (Thunberg, 1781) (Coccmellidae : Coleoptera). Yasushi TAKENOUCHI Biological Laboratory, Sapporo College, Hokkaido University of Education, Sapporo 064. ^^ ^ : bY 7^ /^T> h r>c7)^t^. w^n^w^ww^ In my earlier papers I reported the chromosomes of 80 coccinellid beetle species and hybrid species covering the world (Takenouchi, 1955, 1968, 1976). Fortunately, I have had a chance to study the chromosomes and the sex-determining mechanism of a single species. The male. specimen was captured by me in a bushy area near Shiriuchi hotsprings in the suburbs of Hakodate, Hokkaido, in mid-June, 1978. The taxonomical situation of the species is as follows : Family Coccinellidae Subfamily Coccinellinae Tribe Coccinellini Propylea japonica (Thunberg, 1781) japonica—form The preparation was made according to Smith's squash method (Smith, 1943) and stained in an aqueous solution of 0.6% methyl green and 0.15% basic fuchsin (1 : 1). The slide provided 13 first meiotic metaphases but lacked spermatogonial divisions. As seen in Fig. 1 and 2, the haploid chromosome complement in the male is 10, which is the commonest chromosome number. in the tribe Coccinellini so far studied (Smith, 1953, 1960). Because of a very small difference in size of its components, the Xyp stands out from autosomal bivalents. All the autosomal elements. are of dumbbell shape. In a single cell one disjoins before the others (Fig. 2). According to Smith (1953) Yosida (1949, 1951) studied Propylea japonica for the first time and reported that the haploid number of this species was 10 (9n+Xy) which corresponds to the number obtained in this study. But he could not confirm the true feature of the sex-determining pair.. The reason why he failed is very simple. He used a classical paraffin method which is unsuitable for the cytology of the Coleopteran insects as I pointed out (Takenouchi, 1973). The author wishes to express his thanks to Professor M. Chujo, Meijo University, Nagoya, for the identification of the species.. (D.

(3) Yasushi TAKENOUCHI. IW ••?;-. ••. c? ^. Figs. land 2. First meiotic metaphases of male Propylea japonica. (X 3,600).. References. Smith, S. G. 1943 Techniques for the study of insect chromosomes. Can. Entomol. 75 : 21—34. Smith, S. G. 1953 Chromosome numbers of Coleoptera. Heredity 7 : 31—48. Smith, S. G. 1960 Chromosome numbers of Coleoptera. II. Can. J. Genet, Cytol. 2 : 66—88.. Takenouchi, Y. 1955 Notes on cytology and hybridization in two puzzling species of Epilachna (Coccinellidae -Coleoptera). Annot. Zool. Japan. 28 : 238-243.. Takenouchi, Y. 1968 A modification of the Xyp sex-determining mechanism in a lady-bird beetle, Epilachna pustulosa Kono (Coccinellidae, Coleoptera). Chrom. Inform. Serv. 9 : 25—27. : Takenouchi, Y. 1976 Chromosome numbers and sex chromosomes newly recorded in seventy-six species of coccinellid beetles. Proc. Jap. Acad. 52 : 62—65. Takenouchi, Y. 1973 A revised study of the chromosomes of twenty-four species of Japanese weevil (Coleoptera : Curculionidae). Genetica 44 : 621—632.. (2).

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