528.

Large Japanese Field Mouse

Apodemus speciosus

French: Mulot du Japon / German: Grof 3e Japan-Waldmaus / Spanish: Ratén de campo grande de Japon

Taxonomy. Mus speciosus Temminck, 1844,

Japan .

Apodemus speciosus exhibits significant geographic morphological and genetic variability throughout its range. Different chromosomal races have been described through Robertsonian rearrangement between autosomes, but this 1s not suf-ficient to cause reproductive isolation. In the most recent molecular phylogeny, by Liu Qi and colleagues in 2012, A. speciosus belongs to the Apodemus group in an agrarius subclade, and is sister taxon of a clade including A. chevrieri and A. agrarius . Subspecific taxonomy requires reassessment.

Distribution. Japan.

Descriptive notes. Head—body 80-140 mm,tail 70-130 mm, ear 13-17 mm, hindfoot 22-28 mm; weight 20-60 g. The LargeJapanese Field Mouse is a medium-sized to large mouse with long tail. It has brown to orange-brown dorsal pelage and snow-white belly. Females bear four pairs of mammae. Karyotype 2n = 46-48, FN = 56.

Habitat. In lowlands of central Japan, the Large Japanese Field Mouse was collected along riverbanks, floodplain grassland and tall herbs, and paddyfields broadleaf forests with nut-producing trees are also preferred, in addition to forests and plantations. Y. Takada and colleagues reported in 1999 that populations of this mouse on Izu Islands commonly inhabit crop fields near human habitation, as well as woodlands.

Food and Feeding. Diet includes roots and stems of herbaceous plants, seeds, berries, and to lesserextent insects. It consumes fruits ofJapanese walnut ( Juglans ailanthifolia, Juglandaceae); either it eats the contents immediately after finding walnuts, or it hoards the nuts on the ground (scatter-hoarding) or in underground nests (larderhoarding) for later use. The Large Japanese Field Mouse is also a disperser of Camellia japonica (Theaceae) seeds.

Breeding. Breeding season varies geographically, mainly April/May-September/October in north and October-March in south. Females had average of 3-2 embryos in spring, against 5-6 in autumn. Gestation period is 19-26 days. Litter size is 2-12 (average 4-6).

Activity patterns. Large Japanese Field Mice are terrestrial and nocturnal.

Movements, Home range and Social organization. Home ranges were 7906 m? (diameter 100 m) and 8500 m?* (diameter 104 m) for males, and 3062 m? (diameter 62 m) and 3175 m* (diameter 64 m) for females. Ranges of males overlap randomly while those of females are mutually exclusive, and there is no evidence of pair bonds. Home ranges of both sexes were significantly larger during breeding season.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Abe et al. (2006), Kaneko (1979), Liu Qi etal. (2012), Matsubara et al. (2004), Murakami (1974), Ohdachi et al. (2015), Suzuki et al. (1994), Takada (1983), Takada et al. (1999), Tatsukawa & Murakami (1976), Tomozawa etal. (2010).