著者

宮尾 嶽雄 両角 徹郎 両角 源美 花村 肇 佐藤 信吉 赤羽 啓栄 酒井 秋男

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.72, no.7, pp.187-193, 1963-07-15

被引用文献数

6

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The authors investigated the seasonal differences of sex ratio, body weight, percentage of pregnant female and testicle size in two species of the field mice, Apodemus argenteus and Clethrionomys andersoni, collected from April, 1962 to March, 1963, in the subalpine forestzone (Tsuga diversifolia-Abies Mariesii forest zone, alt. 1,800-2,400m) on Mt. Yatsugatake in Honshu. Toral number of collected specimens was 308 Apodemus ar genteus and 616 Clethrionomys andersoni. 1) The number of males was larger than that of females in all months except August in Clethrionomys andersoni (♀ 56.7%), and July in Apodemus argenteus (♀ 54.6%), during the height of the breeding season (Fig. 1). 2) From the histograms of the body weight, the following tendencies were noted. Young mice appeared from July to October in Clethrionomys andersoni, and from June to September in Apodemus argenteus. Old adults disappeared from November to March in Clethrionomys andersoni, and from August in Apodemus argenteus. In both species, the developmental period of body weight generally coincided with the spring breeding season (Fig. 2 and Fig. 3). The life span of these species was supposed at about 1 year. 3) The maximum monthly pregnancy rate was attained in June in both species (Fig. 4). The yearly average embryo size was 3.3 in Clethrionomys andersoni and 3.9 in Apodemys argenteus. 4) The monthly average testicle sizes were about 10 mm. from April to July in both species. But they were about 4 mm. from October to March (Fig. 5).

著者

宮尾 嶽雄 両角 徹郎 両角 源美 花村 肇 赤羽 啓栄 酒井 秋男

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.73, no.7, pp.189-195, 1964-07-15

被引用文献数

2

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The present paper deals with the distribution and breeding season of Smith's red-backed vole (Eothenomys smithi) in the subalpine forest zone (Tsuga diversiforia-Abies Mariesii forest zone, alt. 1,300-2,400m)on Mt. Yatsugatake in Honshu, Japan. By using snap traps, a survey was made every August in 1957, 1959, 1960 and 1961, and every month from April 1962 to March 1964. 1. In the subalpine forest zone, Anderson's red-backed vole (Clethrionomys adersoni) and the wood mouse (Apodemus argenteus) were the most abundant species. E. smithi is distributed widely in this area, but the population density was in general low, although in some localities it was high, as in areas with haevy undergrowth. E. smithi occurred with Clethrionomys andersoni and there was not observable habitat segregation between them. 2. The average tail length and hind foot length was 43.09mm and 16.32mm, respectively. 3. Pregnant females were found from May to October, and the maximum monthly pregnancy rate was attained in July. The yearly average number of embryoes was 2.3. Out of 32 females examined, 6(18.7%)had three pairs of mammae and 26 (81.3%) had two pairs of mammae. The monthly average testicle sizes increased quickly in spring and attained a maximum in June, after which their size was quickly reduced. 4. It is known that E. smithi occurs in forested regions on Honshu, Shikoku and Kyushu in Japan, but recently Imaizumi (1957) distinguished a new variety E. smithi occurring in the northern part of Honshu (including Mt. yatsugatake) from those in the southern part of Honshu, Shikoku and Kyushu, and he named the former E. kageus. He suggested that E. kageus has two pairs of mammae and that E. smithi has three pairs. The present results, however, show that the color, body measurements and habitat of E. kageus are very close to those of E. smithi, and further that the specimens having both types of mammae are found in the same area on Mt. yatsugatake. Thus the difference in the number of mammae betwwn E. kageus and E. smithi may be due only to individual variation.

著者

宮尾 嶽雄 両角 徹郎 両角 源美 花村 肇 佐藤 信吉 赤羽 啓栄 酒井 秋男

出版者

日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.72, no.5, pp.133-138, 1963-05

被引用文献数

4

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From April, 1962 to March, 1963, the authors collected small mammals (Rodentia and Insectivora) monthly by snap traps in the subalpine forest zone (Tsugadiversiforia-Abies Mariesii forest zone, alt. 1,300-2,400m) on Mt. Yatsugatake in Honshu. Total number of captured mice and voles was 961 with the following proportional breakdown: Rattus rattus 1, Apodemus speciosus 14, Apodemus argenteus 308, Clethrionomys andersoni 616, Anteliomys smithii 20, Microtus montebelli 2. The number of moles and shrews taken was 231 with the following breakdown: Euroscaptor mizura 1, Urotrichus talpoides hondonis 18, Dymecodon pilirostris 151, and Sorex shinto shinto 61. Rattus rattus and Microtus montebelli were found in this area. Apodemus speciosus and Urotrichus talpoides hondonis were only found in the lower part of this grassy area. On the other hand, Apodemus argenteus, Clethrionomys andersoni, Anteliomys smithii, Dymecodon pilirostris, Sorex shinto shinto were widely found in this forest zone. It was noted that the largest number of Apodemus argenteus appeared in spring, but the peak of Clethrionomys andersoni was seen from autumn to winter (Fig. 2). The average embryo sizes of each species were as follows: Apodemus speciosus 5.7, Apodemus argenteus 3.9, Clethrionomys andersoni 3.3, Anteliomys smithii 3.5, Microtus montebelli 3.0, Urotrichus talpoides hondonis 4.5, Dymecodon pilirostris 3.5, Sorex shinto shinto 3.7. The highest capture rate (number of captured small mammals/no. of set traps) occurred in October and the lowest rate in February. They reflect the effect of the population density and the snow fall, etc.

著者

宮尾 嶽雄 両角 徹郎 両角 源美 赤羽 啓栄 酒井 秋男 花村 肇

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.74, no.3, pp.76-81, 1965-03-15

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The authors certified that five species of insectivora inhabit the subalpine forest zone (alt. 1,800-2,400m) of Mt. Yatsugatake. They are Euroscaptor mizura, Urotrichus talpoides, Dymecodon pilirostris, Sorex shinto and Chimarrogale platycephala. From April, 1962 to March, 1964, the authors collected small mammals monthly by snap traps in the subalpine forest zone on Mt. Yatsugatake in Honshu. The total number of captured mice and voles was 1,577. The number of moles and shrews taken was 387 with the following breakdown: Urotrichus talpoides 25, Dymecodon pilirostris 257, Sorex shinto 105. It was noted that larger number of Dymecodon pilirostris and Sorex shinto appeared in June and in winter. Pregnant females were found in May (2 specimens) in Urotrichus talpoides, in May (3) and July (3) in Dymecodon pilirostris, in May (2) and June (5) in Sorex shinto. The average embryo sizes of each species were as follows: Urotrichus talpoides 4.5, Dymecodon pilirostris 3.7, Sorex shinto 3.8. Mammal formula of each species examined are shown in Table 3. The monthly average testicle sizes advance rapidly to the maximum after winter in Dymecodon pilirostris and Sorex shinto, but after which their size are quickly reduced. In Dymecodon pilirostris and Sorex shinto, from the frequency distribution table of body weight, the following tendencies are noted: wintered animals grow repidly and reach maturity from April to July. But breeding ceases in August mainly because the parent generation is rapidly dying off by October, completely so by November. Young come into the populations from August onwards, predominating from August and overwinter without coming into breeding conditions. The life span of these species is supposed to be about 1-1.5 years.

著者

宮尾 嶽雄 両角 徹郎 両角 源美 赤羽 啓栄 酒井 秋男

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.73, no.11, 1964-12-15

著者

宮尾 嶽雄 両角 徹郎 両角 源美 赤羽 啓栄 酒井 秋男

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.72, no.11, 1963-12-15

著者

宮尾 嶽雄 両角 徹郎 両角 源美 毛利 孝之

出版者

日本哺乳類学会

雑誌

哺乳動物学雑誌: The Journal of the Mammalogical Society of Japan (ISSN:05460670)

巻号頁・発行日

vol.4, no.1, pp.29-32, 1968

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The authors collected small mammals on Sado Island which lies in the Japan Sea about 32 km off Niigata and is situated on the northern coast of Central Honshu, the main island of Japan. Collecting was carried out during August 2-5, 1966, using snap traps.<BR>At Marutsuburi (alt. 120 m), we took the specimens listed below. The vegetation of this area was a mixed forest consisting chiefly of <I>Cryptomeria</I> and <I>Quercus. Apodemus speciosus sadoensis</I>, _??_11, _??_4<BR>At Mt. Myoken (alt. 1, 000 m), we took the specimens listed below. The vegetation of this area was shrubs consisting chiefly of <I>Acer</I>.<BR><I>Apodemus speciosus sadoensis</I>, _??_11, _??_9<BR><I>Apodemus argenteus</I>, _??_6, _??_6<BR><I>Microtus montebelli brevicorpus</I>, _??_<BR>Frequency distribution tables of body weight of <I>Apodemus</I> are shown in Tables 1 and 3. Average tail length, hind foot length and testicle size of each species are shown in Table 2. No pregnant females were collected.<BR>We noted that the island form, <I>Apodemus speciosus sadoensis</I>, was larger in body sizes than the mainland form, <I>A. s. speciosus</I>.

著者

宮尾 嶽雄 両角 源美 両角 徹郎

出版者

社団法人日本動物学会

雑誌

動物学雑誌 (ISSN:00445118)

巻号頁・発行日

vol.75, no.4, pp.98-102, 1966-04-15

被引用文献数

2

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This paper deals with the seasonal variation of sex ratio, body weight, number of pregnant females and testicle size in the vole, Microtus montebelli. They were collected in the period from May, 1964 to September, 1965 in the montane zone (alt. 1,400-1,500m) on Mt. Yatsugatake in Honshu. The total number of specimens collected was 335. They are 33 Apodemus speciosus, 5 Apodemus argenteus, 272 Microtus montebelli, 22 Urotrichus talpodes and 3 Sorex shinto. Microtus montebelli was found exclusively in the grassy area of the montane zone. The number of female Microtus montebelli was larger than the males through months except for the months of May and October. Histograms of the body weight tend to indicate that voles grow rapidly in spring and reach maturity in months ranging from May to August. Breeding ceases in September, since the parent generation is rapidly dying off by October and completely so by November. The young generation comes into population from June and predominates in October, and extends through winter without coming into breeding condition. The life span of the vole may be more or less than 1.5 years. Pregnant females were obtained from May to November. The maximum monthly pregnancy rate occurred in June. The average number of embryos was 3.5. The monthly average testicle size increases and generally shows a maximum after winter. The testicle size was quickly reduced in September.