Intra-and inter-specific relationship between the Japanese dormouse and the small Japanese vole.

Research Project

Project/Area Number	10640620
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	生態
Research Institution	Osaka City University
Principal Investigator	KAWAMICHI Takeo Department of Biology, Osaka City University Associate Professor, 理学部, 助教授 (00047333)
Co-Investigator(Kenkyū-buntansha)	川道武男大阪市立大学, 理学部, 助教授 (00047333)
Project Period (FY)	1998 – 1999
Project Status	Completed (Fiscal Year 1999)
Budget Amount *help	¥2,100,000 (Direct Cost: ¥2,100,000) Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000) Fiscal Year 1998: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	dormouse / vole / hibernation / daily torpor / home range / sex ratio / pairing / 行動圏 / 産子数
Research Abstract	To investigate the intra- and inter-specific relationship between the Japanese dormouse Glirulus japonicus and the small Japanese vole Apodemus argenteus, 252 nest boxes were set on tree trunks on Mt. Asama, Nagano Prefecture. These animals were live-captured in the nest boles in the morning, marked with toe-clipping and micro-tips, and released. A total of 80 animals were captured for dormice and 302 for voles in 1998 and 1999. Almost everyday from spring to autumn, all nest boxes were checked and micro-tip ID numbers were read outside the nest boxes. Twenty-eight Japanese dormice were radio-tracked to locate their nest sites. Dormouse : The mean home range was 0.5 ha for females and 1.52 ha for males. Male ranges were greater than female ones. Female ranges were only partially overlapped with each other. They used nest boxes for reproduction and more often for daytime rest, but not for hibernation. They frequently changed nest sites without nesting material, because they showed daily torpor. Population density was 0.7 animals/ha, and the sex ratio was almost 1 : 1. Two or more years old individuals were accounted for 44% in females, and 64% in males, indicating long longevity. Vole : The mean home range was 0.1 ha for females and 0.14 ha for males. Intra-sexual overlap was only partial in both sexes. Large males often shared the same nest boxes with particular females, indicating pairing. The voles used nest boxes mostly for reproduction. Reproductive seasons were twice ; in the spring, larger females gave birth earlier, and more males were born, while in the autumn negative correlation was found between mother body mass and their daughters' body mass. Occasionally, both species shared the same nest boxes, indicating the lack of antagonistic relationship. This common sharing always occurred at the nest boxes in which the vole had constructed the spherical reproductive nests.