ハナウドゾウムシの染色体の再検討
4
0
0
全文
(2) Vol. 20, No. 2 Journal of Hokkaido University of Education (Section II B) January 1970. A Revised Study on the Chromosomes of a Weevil, Catapionus viridimetallicus Motschulsky (Coleoptera, Curculionidae). Yasushi TAKENOUCHI Biological Laboratory, Sapporo College, Hokkaiclo University of Education. Received October 16, 1969 ftrt -%: -^-1> I'- •/ •> A •>'®%&?oS^-'f-. The recent improvement of preparation techniques has rendered the squashed slide much more suitable for the karyological research of insects than the classical sectioned slide which does not give the detailed structure, especially, of the small chromosomes of coleopteran insects.. In his first investigation on the chromosomes of the weevils, Curculloniclae, the author studied the male germ cells in sectioned slides of the Catapioiltt.s vii'idimefalliciis Motschulsky, and noticed that the species had 2n=20, n=10 and the sex-chromosome mechanism is the simple XY which belongs to the category of Xyr after Smitli (see p. 442, Takenouchi, 1953 and p. 333, Takenouchi, 1955 ; Smith, 1953). As to the advancement of his chromosome survey of the Curculionidae, the autlier has studied anew the above results, and a revised investigation was carried out in the spring of 1969. The present paper describes the results of this study. Two males collected on Mt. Hakodate, Hakodate, in May 1963, three males at Tmarimura, Furuugun, Hokkaido, in June 1964, and five males at the foot of Mt. Molwa, Sapporo, in May and June 1969, constitute the material for the study. For the first five specimens the Smith squash method (Smith, 1.943) was adopted and for the last five insects, the squash method stained with 10% acetic gentian violet was applied. The diploid number of chromosomes of this species was 20 in spermatogonial metaphases as reported in the former papers (Fig. 1) (Takenouchi, 1953, 1955). The diploid complement consists of eight large metacentric chromosomes, four small metacentnc ones, six small chromosomes of obscure shape, one large submetacentric chromosomes and a comparatively. large telocentric chromosome. The last two elements are the X and Y, respectively. The longer arm of the X approximately corresponds in size to the Y. There are 10 bivalent chromosomes at first metaphase (Figs. 3-5). Four large bivalents being equivalent to 4 pairs of large metacentric chromosomes in the diploid set and a large heteromorphic pair were outstanding in the haploid complement. In superficial magnitude, the longer arm of the X corresponds again to the Y. The Y associates with the longer arm of the X in an end-to-end connection. According to Smith's interpretation such a sex-determining mechanism is called the neo-XY (Smith, 1953). Therefore the larger submetacentric element is the neo-X and.
(3) A Revised Study on the Chromosomes of a Weevil. Figs. 1-6. Photomicrographs of the chromosomes of male Catapionus viridimetalticns ( x ca 2,800). 1. Spermatogonial metahase. 2. Pachytene. 3. Prometaphase of the first meiotic clivision. 4 and 5. First meiotic metaphses. 6. A tetraploicl spermatocyte at metaphase with 20 bivalents.. the rod-shaped Y is the neo-Y. No heteropycnotic bodies were observed in any stage of the first prophase as seen in Fig. 2. The neo-XY bivalent is not always evident in every metaphase of the first division, sometimes it is impossible to detect it. Out of more than 150.
(4) Yasushi Takenouclii. weevil species so far studied cytologically, the record of neo-XY sex-determining system. was reported by Smith (1952) in Sitophilus ( = Calandra) oryzae Linne and by Takenouchi (1963) in Trichalophns albonotatus Motschulsky. Comparatively numerous tetraploid spermatocytes with 20 bivalents were observed in a male animal obtained at the foot of Mt. Moiwa (Fig. 6). Such a phenomenon was formerly observed by the author in C. mridhnetallicits and in a willow weevil, Cryptorrhynchi.di.iis lapathi Linne (Takenouchi, unpublished). The author is grateful to Mr. ~M. Takamatsu for his kind help during the course of the investigation.. Literature Smith, S. G. 1943. Techniques for the study of insect chromosomes. Can. Entomol. 75 : 21-34. 1952. The cytology of Sitophilus (= Calandra') oryzae (L.), S, granarius (L.), and some other Rhynchophora (Coleoptera). Cytologia 17 : 50-70. 1953. Chromosome numbers of Coleoptera. Heredity 7: 31-38. Takenouchi, Y. 1953. Preliminary notes on the chromosomes of some weevils. Zool. Mag. 62 : 441-444. 1955. A chromosome survey in thirty species of the weevils (Curculionidae, Coleoptera), Jap. Jour. Zool. 11: 425-441. 1963. A further investigation on the chromosomes in twenty-three species of weevils (Curculionidae, Coleoptera). Jour. Hokkaiclo Gakug.ei Univ. 2nd Ser. 13 : 160-174..
(5)
関連したドキュメント
In Section 3 the extended Rapcs´ ak system with curvature condition is considered in the n-dimensional generic case, when the eigenvalues of the Jacobi curvature tensor Φ are
Analogs of this theorem were proved by Roitberg for nonregular elliptic boundary- value problems and for general elliptic systems of differential equations, the mod- ified scale of
Then it follows immediately from a suitable version of “Hensel’s Lemma” [cf., e.g., the argument of [4], Lemma 2.1] that S may be obtained, as the notation suggests, as the m A
Definition An embeddable tiled surface is a tiled surface which is actually achieved as the graph of singular leaves of some embedded orientable surface with closed braid
Our method of proof can also be used to recover the rational homotopy of L K(2) S 0 as well as the chromatic splitting conjecture at primes p > 3 [16]; we only need to use the
Correspondingly, the limiting sequence of metric spaces has a surpris- ingly simple description as a collection of random real trees (given below) in which certain pairs of
We study the classical invariant theory of the B´ ezoutiant R(A, B) of a pair of binary forms A, B.. We also describe a ‘generic reduc- tion formula’ which recovers B from R(A, B)
For X-valued vector functions the Dinculeanu integral with respect to a σ-additive scalar measure on P (see Note 1) is the same as the Bochner integral and hence the Dinculeanu
