122.

Taiwan Vole

Alexandromys kikuchii

French: Campagnol de Taiwan / German: Taiwan-Wihimaus / Spanish: Topillo de Taiwan

Other common names: Kikuchi’s Field Vole

Taxonomy. Microtus kikuchii Kuroda, 1920, Mt. Morrison, Taiwan, 10,000 ft (= 3048 m).

Alexandromys kikuchii is closely related to A. oeconomus and A. montebelli . In the past, A. kikuchii also was classified in the genus Volemys . Monotypic.

Distribution. Endemic to rugged mountainous ranges in E Taiwan .

Descriptive notes. Head-body 100-140 mm, tail 80-98 mm. Males are significantly heavier (mean weight 43-2 g) than females (37 g). The Taiwan Vole is moderately large, with long, indistinctly bicolored tail, ¢.60% of head-body length. Ears are notably long. Dorsum is fulvous brown, and belly is grayish. Skull is deep and rather narrow across zygomatic arches. Braincase is long, orbital region 1s not too constricted, and sagittal crest is shallow. M” has four inner and 3-4 outer salient angles; posterior cup is short. M, hasfive closed triangles between posterior loop and simple anterior cup.

Habitat. Grasslands, shrublands, and coniferous, broadleaf, and mixed forests at elevations of 1500-3670 m. The Taiwan Vole is abundant above 2000 m in coniferous forests and alpine grasslands of Yushan cane ( Yushania niitakayamensis, Poaceae).

Food and Feeding. In cafeteria experiments, the Taiwan Vole did not show much preference for particular species of plants, except for false helleborine ( Veratrum formosanum, Melanthiaceae), which was clearly favored. Another study found Yushan cane to be major food plant in alpine meadows. Yushan cane has higher nitrogen content than other plant species in alpine ecosystems and is one of the most palatable foods of Taiwan Voles. Feeding preference can be explained by plant chemical constituents and varies between seasons; e.g. shots were most preferred in May and leaves in October and January. Overall, leaves were most preferred, and stalks and rhizomes were least preferred. Taiwan Voles climb or cut down stalks 3-5 cm from the ground to reach leaves that are clipped off branches. A leaf is eaten from the petiole end, and tip is thrown away. Cut and discarded plants result in large amounts oflitter on the ground.

Breeding. Taiwan Voles reproduce in March-August.

Activity patterns. Diurnal activity of Taiwan Voles has two peaks: 04:00-10:00 h and 16:00-21:00 h.

Movements, Home range and Social organization. Home ranges of Taiwan Voles average 2072 m? for adult males and 1125 m? for adult females during non-breeding period and 1826 m* for males and 1684 m* for females during breeding season. Average overlap in home ranges is significantly higher (77-1%) in mated pairs than in pairs that do not breed (41:8%); this is particularly evident for females. Taiwan Voles live in mated pairs or in family groups. Mating system is monogamous, and most males mate with one female. No litters were found to be sired by multiple fathers. A male can mates with more than one female in different breeding seasons and when the first female is no longer present. Captive Taiwan Voles spent more time with their partner than with a strange individual. During behavioral trials, individuals were not very aggressive toward other individuals. Females occasionally vocalize, but males are silent.

Status and Conservation. Classified as Near Threatened on The IUCN Red List (as Microtus kikuchii). This categorization is justified by small extent of occurrence of the Taiwan Vole (less than 5000 km?) and narrow habitat requirements that restrict it to high elevations. Currently, there are no known conservation threats.

Bibliography. Aoki & Tanaka (1941), Chappell et al. (2016), Ho Hanchih & Lin Yuteh (2007), Kaneko (1987), Mekada et al. (2001), Shenbrot & Krasnov (2005), Wu Jungsheng et al. (2012), Yeh Suhan et al. (2012).