Zoological Studies

Vol. 45 No. 4, 2006

Population Ecology of the Southeast Asian House Mouse (Muridae: Mus musculus castaneus) Inhabiting Rice Granaries in Taiwan

Shu-Yu Wu1,3, Yu-Teh K. Lin2,3, and Hon-Tsen Yu1,3,*

1Institute of Zoology, National Taiwan University, Taipei, Taiwan 106
2Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, Taiwan 106
3Department of Life Science, National Taiwan University, Taipei, Taiwan 106

Shu-Yu Wu, Yu-Teh K. Lin, and Hon-Tsen Yu (2006) We studied the population ecology of a house mouse subspecies, Mus musculus castaneus, in northeastern Taiwan. Populations living in rice granaries offer a unique opportunity to understand the house mice in a commensal habitat. Environments in rice granaries fluctuate both spatially and temporally in terms of food and habitat availability, and mortality risk, due to the pulsed removal of rice sacks and the practice of poisoning. The results indicated that the pulsed removal of rice sacks in individual rooms did not noticeably reduce the size of the house mouse population in granary 1, whereas the total removal of rice sacks from granary 2 severely altered the habitat and precipitated a sharp decline in the mouse population size. In contrast, poisoning considerably altered population structures. The age structure changed from ones with a high proportion of young animals to a clearly inverted triangular structure, indicating a strong effect of poisoning on recruitment of the young. However, poisoning did not change the sex ratio, nor disrupt breeding activities of breeders. Continuous breeding activities throughout the year and rapid reproductive rates apparently have allowed M. m. castaneus to successfully persist in rice granaries. We also discuss the body growth patterns and spatial distribution patterns of the house mouse in granaries.

Key words: Mus musculus castaneus, Commensal habitats, Rice granary, Population structure, Poisoning.

*Correspondence: Tel: 886-2-33662456. Fax: 886-2-23638179. E-mail:ayu@ntu.edu.tw