It is known that the development of roadway systems can benefit bats, particularly cave- and crevice-roosting species, by providing novel roosting resources, e.g., abandoned tunnels and underpasses. However, the usage of operational road tunnels by bats, and its pros and cons are often overlooked. In the present study, we investigated bat diversity in 18 road tunnels in a subtropical forested mountain in Taiwan from 2018 to 2019. A total of 139 insectivorous bat sightings were recorded from 13 tunnels and 76.3% of the samples were identified to 12 species. Surprisingly, 75% of the species were previously regarded as non-cave specialists. Bat occurrences show spatial, temporal, and taxonomic aggregations as around 90% of the observations were contributed by four morpho-species from five tunnels in the summer and fall seasons. The among-site variations in species composition can be explained by tunnel morphology and presence of operational streetlight by the entrances. Since roadkill and grounded individuals, particularly juvenile Pipistrellus, were often found during surveys, these tunnels may act as ecological traps rather than suitable roosts to bats. Future confirmation of the roles of these tunnels to bats is necessary by measuring fitness through behavioral observations and long-term monitoring.

Three vespertilionid bats were captured from Amami-Oshima Island, and had an average forearm length of 35 mm and average body weight of 8 g. From the side of the bat skulls, the ridge of the crown was slightly curved at the base of the snout; the second upper premolar (P²) in the bats was relatively large; the male baculum was shaped like an elongated, 3-mm-long spear tip and was very similar in both shape and size to that of Hypsugo pulveratus. The phylogenetic tree inferred from the mitochondrial COI gene sequences revealed that these bats clustered with H. pulveratus. Therefore, the bats from Amami-Oshima Island were identified as H. pulveratus. The present paper lists and depicts the morphological differences between H. pulveratus and H. alaschanicus so far known from the territory of Japan. Finally, genetic analysis based on the barcoding gene sequences revealed that these species formed distinct clades.

Mutations in genes causing leucism are often accompanied by serious disease limiting individual fitness in laboratory animals. Mammalian species with all-white fur exist in the wild; however, the causative genes have not yet been identified, because of the difficulty of the forward genetic approach—comparisons between individuals with different phenotypes. In this study, we conducted linkage analyses using six candidate gene markers on a wild leucistic female grey red-backed vole (Myodes rufocanus) and inbreeding F1 and F2 offspring displaying variations in coat colors, agouti, and leucism. We found that the white-furred variant was associated with a specific Kit allele characterized by a nonsynonymous substitution at amino acid position 604, leading to the replacement of glycine with arginine. In addition, the leucistic phenotype was accompanied by a small portion of black hairs, which increased with growth. Our results showed a candidate gene causing leucism in viable wild animals and provided an opportunity to consider the necessity to study growth-associated traits for coat color analyses.

Quaternary environmental change provided opportunities for rapid population expansion; however, the process of building the population spatial structures remains poorly understood. In this study, we determined the mitochondrial cytochrome b and control region sequences of 43 individuals of the large Japanese wood mouse (Apodemus speciosus) from Hokkaido, northern Japan and analyzed these data along with those from 40 other individuals. Consistent with the findings of our previous study, we found that two rapid expansion events, after the last glacial maximum (LGM) and Marine Isotope Stage (MIS) 4, shaped population genetic pattern of A. speciosus in Hokkaido. In northeastern Hokkaido, several ancient lineages that originated during MIS 3 were detected, whereas central Hokkaido was dominated by haplotypes descended from a single lineage that survived the LGM, suggesting that the populations of western part of Hokkaido were newly formed by westward migration from eastern Hokkaido during the post-LGM warm period. Alternatively, as post-LGM vegetation recovery is thought to have occurred gradually from west to east in Hokkaido, population expansion started in the west and moved gradually to the east, resulting in eastward haplotype movement; thus, western and eastern Hokkaido may have served as the haplotype source and sink, respectively.

A bat was rescued from Okinawajima Island, Ryukyu Archipelago, Japan in November 2021. Observing the external characteristics, we identified it as the black-bearded tomb bat, Taphozous melanopogon Temminck, 1841, which is mainly distributed in tropical Asia. To our knowledge, this is the first record of this species in Japan. However, we infer that it was accidentally only visiting and not established on Okinawajima Island.

Ticks are vectors that transmit zoonotic pathogens via wildlife hosts. Although the distribution of ticks varies with the expansion of wildlife populations, few studies in Japan have tracked changes in the distribution of hosts, ticks, and infectious diseases on a regional scale. We conducted a follow-up investigation of a previous study conducted from 1988 to 1993 on the distribution of ticks as potential vectors of spotted fever group rickettsiae on Boso Peninsula, Japan, a Japanese spotted fever (JSF)-endemic area. Haemaphysalis cornigera, H. kitaokai, and H. megaspinosa ticks expanded their distribution to the west of Futtsu City following the expansion of sika deer (Cervus nippon) and wild boar (Sus scrofa) populations. The distributions of H. flava and H. longicornis remained almost unchanged from 1988 to 1993. None of the tick species showed a distribution that completely coincided with the area of JSF occurrence at any time point. Rickettsia species, the causative agent of JSF, might have been transmitted by multiple tick species in this region.

千葉県房総半島におけるマダニ類と野生動物の分布の関連性．マダニ類は， 野生動物を介して様々な人獣共通感染症の病原体を媒介する公衆衛生上重要な生物であり，その分布は宿主 である野生動物の個体数増加や分布拡大によって変化している可能性がある。しかし，マダニと宿主動物の 分布変化および感染被害の拡大との関係を広域スケールで追跡した研究事例は日本ではほとんどない。本研 究では，マダニ媒介性感染症「日本紅斑熱」の流行地域である千葉県房総半島において，紅斑熱群リケッチ アを媒介するマダニ類の分布を 2013 年から 2020 年に調査し，1988–1993 年時の調査結果と比較するととも に，日本紅斑熱の感染拡大状況との対応を調べた。その結果，ニホンジカ（Cervus nippon）やイノシシ（Sus scrofa）の拡大方向と同じように西側の富津市へ分布を拡大したツノチマダニ（Haemaphysalis cornigera）， ヒゲナガチマダニ（H. kitaokai），オオトゲチマダニ（H. megaspinosa）が確認された。一方，1988–1993 年時 とほとんど分布域が変わらなかったキチマダニ（H. flava）やフタトゲチマダニ（H. longicornis）も確認され た。どのマダニ種の分布域も，単独では，どの時点においても日本紅斑熱患者発生地域と完全に一致しなかっ た。房総半島では病原体リケッチアは複数のマダニ類によって媒介されている可能性がある。

Relatively few studies have investigated host-tick relationships in island environments. To assess the relationships, we captured a total of 51 rodents (Norway rat, n = 29; black rat, n = 22) from which a total of 56 ticks were collected to assess host-tick relationships on Mikura-shima Island, Izu Islands, Japan. We also collected two ticks from a free-ranging cat and a tick from a human resident on the island. The 53 morphologically identifiable ticks were Ixodes granulatus, whose distribution on Mikura-shima Island was not previously reported. Interestingly, the tick infestation rates significantly differed between two rodent species: 44.8% (n = 29) in the Norway rats and 4.5% (n = 22) in the black rat. This insight prompts consideration of the mechanisms behind the differential tick-infestation rate in wildlife hosts and infectious disease transmission in rodent-dominated ecosystems. This study is also the first record of this ixodid infesting domestic cats and a human from the Izu Islands and is the second case of this ixodid biting a human in Japan. Future work should characterize the tick fauna of the island environment and the potential risks of tick-borne diseases.

ドブネズミとクマネズミにおける異なるマダニ寄生率，および御蔵島からの ミナミネズミマダニ Ixodes granulatus の分布とそのネズミ，イエネコ，ヒトへの刺咬事例の初記録．島嶼域 における移入ネズミ類とマダニの関係を評価した研究は比較的少ない．本研究では，伊豆諸島の御蔵島にお けるマダニとホストの関係を明らかにするために，51 頭のネズミ（ドブネズミ 29 頭，クマネズミ 22 頭） を捕獲し，これらから 56 頭のマダニを採集した．また，ノネコから 2 頭と島民から 1 頭のマダニを採集した． 種同定が可能であった 53 頭のマダニのすべてがミナミネズミマダニ Ixodes granulatus と同定され，御蔵島 において本種の初めての分布記録となった．興味深いことに，2 種のネズミの間でマダニの寄生率が異なり， ドブネズミが 44.8%（n = 29），クマネズミが 4.5%（n = 22）であった．この結果は，ネズミ類が優占する生 態系における宿主間の寄生率の違いや感染症伝播プロセスのメカニズムの解明に示唆を与えるであろう．ま た，本研究は伊豆諸島においてミナミネズミマダニがイエネコとヒトを刺咬した初めての報告になる．特に， ヒトの刺咬例としては私たちが知る限り日本で 2 例目となる．島嶼におけるマダニの基本的な情報について はまだ不足しており，今後のマダニ相の把握やマダニ媒介感染症の潜在的リスクの評価が求められる