Myotis bombinus Thomas 1906

495.

Far Eastern Myotis

Myotis bombinus

French: Murin bourdon / German: Ostliche Fransenfledermaus / Spanish: Ratonero abejorro

Taxonomy. Myotis nattereri bombinus Thomas, 1906,

Japan, “Tano, Miyasaki Ken, Kiushiu [Japan]. 300’ [= 152 m].”

Subgenus Myotis; myotis species group. Myotis bombinus is often included as a subspecies of M. nattereri, but genetic data place it closer to M. pequinius and possibly M. schaubi, M. chinensis, and M. escalarai than to M. nattereri, although some genetic studies found differing relationships. It has been suggested the amurensis is a distinct species. Two subspecies recognized.

Subspecies and Distribution. M.b.bombinusThomas,1906—NCMongolia,SWRussia,NEChina(HeilongjiangandJilin),andKoreanPeninsula(includingJejuI).

M. b. amurensis Ognev, 1927 — much ofJapan (including Kuchinoerabu-jima I).

Descriptive notes. Head—-body 41-52 mm, tail 38-45 mm, ear 12-19 mm, hindfoot 7-12 mm, forearm 37-42 mm; weight 5-10 g. Fur of the Far Eastern Myotis is soft and woolly. Dorsal pelage is medium brown (hairs with dark bases and paler brown tips); venteris paler. Face is pinkish brown, and ears and membrane are brown. Ears are long and narrow, with narrow tips; tragus is long, narrow, and markedly recurved. Uropatagium has stiff bristles at back margin, and membraneitself is surprisingly thick for the genus. Wing attaches to bases of toes, and calcaris long, lacking postcalcariallobe. Skull is long and robust, with comparatively long braincase and short rostrum; and small P? is in tooth row orslightly intruded from it. Chromosomal complement has 2n = 44 and FNa = 50 (Japan).

Habitat. ‘Temperate forests at low and high elevations. Far Eastern Myotis reportedly forage in woodland habitats.

Food and Feeding. Diet consists mainly of Lepidoptera, Coleoptera, Diptera, Trichoptera, and Araneae. Far Eastern Myotis can hover in flight and generally fly less than m aboveground when foraging.

Breeding. Far Eastern Myotis are seasonally monoestrous. Copulation takes place in autumn before hibernation, with delayed fertilization. Females give birth to one young in early June in Kyushu. Females reach sexual maturity by their first breeding season the following year and are often pregnant in their first year. Female pregnancy ratio is extremely high, with nearly all females captured during the breeding season being pregnant. Far Eastern Myotis are philopatric, with a strong homing instinct, and generally remaining near their place of birth throughout their life. Maximum longevity is apparently 20 years of age.

Activity patterns. Far Eastern Myotis prefer to roost in humid caves in winter and tree hollows in summer. They leave their roosts c.1 hour after sunset to forage through the night and are more active when temperatures are warmer. They hibernate in winter (November-March). Some populations appear to be migratory (not in Korea). Calls are steep FM sweeps, with start frequencies of 88-5-134-8 kHz, end frequencies of 17-2-25-3 kHz, peak frequencies of 39-56-9 kHz, durations of 2-4-3-3 milliseconds, and interpulse intervals of 52-2-90-5 milliseconds in Korea. Recordings in Kagoshima Prefecture, Japan, had average end frequency of 28-4 kHz (25-3-33-2 kHz) and peak frequency of 37-5 kHz (29-8-51-2 kHz).

Movements, Home range and Social organization. Far Eastern Myotis are known to roost in small groups. Females form maternity colonies with their young while pregnant and nursing, with as many as ¢.200 individuals. Males can occasionally be found in maternity colonies.

Status and Conservation. Classified as Near Threatened on The IUCN Red List. The Far Eastern Myotis appears to be relatively rare and might be declining in some regions. Deforestation and other human disturbance are likely its mostsignificant threats.

Bibliography. Abe et al. (2005), Fukui et al. (2015), Funakoshi (1991), Harada & Yoshida (1978), Horaéek & Hanak (1984), Jo Yeong-Seok et al. (2018), Kawai et al. (2003), Ohdachi et al. (2009), Ono & Obara (1994), Park Su-Gon et al. (2015), Puechmaille, Allegrini et al. (2012), Smith & Xie Yan (2008), Tsytsulina (2008f), Yamasaki (2004), Yoon Myung-Hee (1990), Yoshiyuki (1989).