Zoological Studies

Vol. 43 No. 3, 2004

Spatial Organization of a Forest-Dwelling Murid Rodent, Niviventer coxingi, in Subtropical Central Taiwan

Hai-Yin Wu1,*, Hon-Tsen Yu2

1Institute of Natural Resources, National Dong Hwa University, Hualien, Taiwan 974
2Graduate Institute of Zoology and Department of Life Science, National Taiwan University, Taipei, Taiwan 106

Hai-Yin Wu and Hon-Tsen Yu (2004) Hypotheses have been proposed that, for rodents, food type determines the spacing pattern of females, while the availability of potential mates determines the spacing pattern of males. For a frugivorous-omnivorous species such as Niviventer coxingi, females are hypothesized to be territorial or widely dispersed, while males should be non-territorial and widely ranging. The peculiar life history traits of female N. coxingi should further strengthen the constraints they exert on male spacing behavior. In this study, we attempted to examine sexual differences and seasonal variations in the spacing patterns of N. coxingi. A population was studied for 17 mo from Jan. 1982 through May 1983 by the mark-recapture method in a 9-ha grid at the Experimental Forest of National Taiwan University at Chitou, central Taiwan. Home range areas were larger in males than in females. Seasonal home range areas of the 2 sexes significantly differed in autumn 1982. Compared with adult females, adult males had greater mean and maximal inter-capture distances, and greater shifts in seasonal activity centers. Correlations between body weights and indices of spacing behavior (inter-capture distances and home range areas) were positive in males and negative in females. Inter-male home range overlap indices were higher than inter-female and inter-sexual overlap indices, especially in autumn 1982. The results suggest that the spacing pattern of N. coxingi is characterized by smaller and widely dispersed home ranges for females, larger home ranges for males, and a higher degree of intra- and inter-sexual home range overlap for males in the breeding season. The mating system is most likely promiscuous. The male-biased population structure, low reproductive intensity of the already scarce females, and the availability of food and suitable habitat may be responsible for the sexual differences and seasonal variations of the spacing behavior.

Key words: Home range, Mating system, Population density, Spacing pattern, Territoriality.

*Correspondence: Fax: 886-3-8633260. E-mail: hywu@mail.ndhu.edu.tw