論文 - 小林　峻

First record of non-flying mammalian contributors to pollination in a tropical montane forest in Asia

Kobayashi Shun, Panha Somsak, Seesamut Teerapong, Nantarat Nattawadee, Likhitrakarn Natdanai, Denda Tetsuo, Izawa Masako

ECOLOGY AND EVOLUTION ( Ecology and Evolution )  11 ( 24 ) 17604 - 17608   2021年12月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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An attempt of the predation avoidance mechanism of Tsuda’s giant stick insect, Megacrania tsudai (Phasmatodea: Phasmatidae), based on the spectral reflectance of the insect and a Pandanus odoratissimus leaf

Kajiwara Y., Kobayashi S., Mochida K., Fujimoto S., Yamahira K., Izawa M. (担当範囲: データの収集、執筆)

The Biological Magazine, Okinawa ( 沖縄生物学会 )  59   51 - 56   2021年05月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Flower visitors of Parkia sumatrana (Leguminosae) in northeastern Thailand

Kobayashi S., Panha S., Placksanoi J., Waengsothorn S., Denda T., Izawa M. (担当範囲: データの収集、解析、執筆)

Tropical Natural History   21   200 - 208   2021年04月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Rat- and bat-pollination of Mucuna championii (Fabaceae) in Hong Kong

Kobayashi S., Gale S. W., Denda T., Izawa M. (担当範囲: データの収集、解析、執筆)

Plant Species Biology   36   84 - 93   2021年 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Mucuna (Fabaceae) species possess gullet-type flowers that open explosively and which are thought to be specifically adapted for bat- or bird-pollination. However, recent studies have shown that non-flying mammals are also important pollinators of this genus in Asia. Here we report on the pollination system of Mucuna championii (endemic in southeast China) in Hong Kong. As is typical for the genus, explosive opening is essential for fruit set, but flowers are unable to open in the absence of manipulation by an effective pollinator. Camera trap surveys of three individuals revealed both chestnut spiny rats (Niviventer fulvescens) and short-nosed fruit bats (Cynopterus sphinx) to be capable of triggering explosive opening. The number of flowers opened by each species did not differ significantly, and both removed most pollen grains from the flowers they visited, but either species visited different individuals. Sucrose-rich nectar was secreted by flowers throughout the day. Our results reveal that M. championii can be pollinated by both rats and bats, with this representing only the second report of rat-pollination in tropical Asia. The sympatric M. birdwoodiana of ten occurs in close proximity to M. championiiand has an overlapping flowering season, suggesting that pollinator segregation may have played a role in shaping the evolutionary ecology of these two species.

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Flower Visitors of Parkia sumatrana (Leguminosae) in Northeastern Thailand

Kobayashi S.

Tropical Natural History ( Tropical Natural History )  21 ( 1 ) 200 - 208   2021年 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Activity pattern and resource use of two Callosciurus species in different habitats in northeastern Thailand.

Kobayashi S., Placksanoi J., Waengsothorn S., Aryuthaka C., Pnaha S., Izawa M (担当範囲: データの収集、解析、執筆)

Raffles Bulletin of Zoology   68   654 - 661   2020年07月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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Some squirrel species can adapt to areas of extensive human ctivities. However, few studies have compared the behaviour of such squirrels in human activity areas with that in their natural forest areas in the tropics. This study describes the activity pattern and resource use of Callosciurus finlaysonii and C. caniceps in a small residential area located in the dry evergreen and dry dipterocarp forests in Sakaerat Biosphere Reserve, Thailand, by using route census survey. Both species were active in the morning and evening, just as they are in the forests, but the frequency of detection of C. finlaysonii was higher than that of C. caniceps. Intraspecific interactions were frequently observed in C. finlaysonii; however, interspecific interactions were not observed. Callosciurus finlaysonii used buildings and electric wires located above ground in open areas as pathways, whereas C. caniceps was not observed in open areas. Callosciurus finlaysonii consumed a greater diversity of food items than C. caniceps, including fruits, leaves, flowers, and seeds, whereas C. caniceps fed mainly on fruits/seeds. The present study showed that C. finlaysonii can use human activity areas. Callosciurus finlaysonii probably use the human activity area owing to the presence of fewer natural predators, its ability to survive in different type of environments, as well as its wide feeding habits, and the presence of fewer competitors. However, it was observed that C. caniceps scarcely used human modified areas.

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Effects of different pollinators and herbivores on the fruit set height of the mammal-pollinated tree-climbing vine Mucuna macrocarpa

Kobayashi S.*, Denda T., Liao C-C., Lin Y-H., Placksanoi, J., Waengsothorn, S., Aryuthaka, C., Panha, S., Izawa M.

Journal of Forest Research ( Journal of Forest Research )  25 ( 5 ) 315 - 321   2020年05月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Although different flower-visiting frequencies and behaviors are known to cause differences in fruit set rates, the effects of different pollinators on the fruit set position are unclear. The climbing vine Mucuna macrocarpa (Fabaceae) needs mammalian pollinators for fruit set. This species is widely distributed in Asia and is pollinated by different mammals in different regions. This study assessed the effects of different pollinators, including their ability to fly, and of herbivores on the fruit set height of M. macrocarpa. The heights of inflorescences and fruits were measured in Kyushu, Okinawa-jima Island (Okinawa), Taiwan, and Thailand. Flying mammalian pollinator (bat) activity was recorded in Okinawa, and non-flying mammalian pollinator activity was recorded in the other three regions. The flowers were observed from the ground to canopy levels in all regions; no fruits were observed at the ground level on Okinawa, whereas fruits were observed from the ground to the canopy levels in Kyushu, Taiwan, and Thailand. In Kyushu, however, fruits were less frequently observed at the ground level. Although pollinators visited flowers located near the ground level, camera traps frequently recorded sika deer (Cervus nippon) feeding on the flowers and fruits near the ground level. Our data show that both the flying ability of pollinators and the density of large-sized herbivores affect the fruit set position.

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Predation on endangered species by cats in the northern forests of Okinawa-jima Island, Japan

Shun Kobayashi, Takaya Kinjo, Yubi Kuroda, Michio Kinjo, Yoko Okawara, Masako Izawa, Manabu Onuma, Atsushi Haga, Yumiko Nakaya, Takashi Nagamine

Mammal Study ( Mammal Study )  45 ( 1 ) 63 - 70   2020年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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Okinawa-jima Island is a part of the Ryukyu Archipelago, Japan and some endemic animals occur. Many of the native animals are limited to the northern part of this island. Here, we examined the predation effect by domestic cats on native species in the northern part of the island. Route surveys were conducted from September 2017 to February 2018, and cats were captured from 2013 to 2018. In total 60 scats (36 by route surveys and 24 from seven captured cats) were collected. At least 16 animal species were found in domestic cats’ scats. Traces of endemic Okinawa spiny rats (Tokudaia muenninki) were the most frequently found from scats collected by route surveys (61.1% in total; 71.4% in the core route, set around the distribution area of Okinawa spiny rats), followed by Ryukyu long-furred rats (Diplothrix legata) (16.7% in total; 21.4% in the core route). Our results showed that domestic cats might exert a significant predation pressure on native endemic vertebrates, especially on Okinawa spiny rats.

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Dietary habits of wintering Pale Thrush Turdus pallidus in the urban green environment of subtropical Okinawa-jima Island, Japan

Kobayashi Shun, Yoshida Wakako, Ui Hiroaki, Okawara Yoko, Izawa Masako

ORNITHOLOGICAL SCIENCE ( Ornithological Science )  18 ( 2 ) 205 - 213   2020年01月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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ヤンバルクイナの餌種一覧

小林 峻, 井ノ口彰良, 中谷裕美子, 長嶺 隆, 佐々木健志, 伊澤雅子

沖縄生物学会誌   57   211 - 227   2019年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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Food list of the endangered Okinawa rail Gallirallus okinawae (Gruiformes: Rallidae) was made by summarizing the results from previous studies, together with new identification of previously not-identified specimens, and the newly analyzed 12 additional samples. From the 234 individuals’ stomach content data, at least 123 species of animals and 35 species of plants were recorded as food items, indicating that this rail is generalist feeding various animals and plants. On the other hands, land snails and insects were found with high frequencies in all previous studies as well as the present study, indicating their importance as food items of the Okinawa rail. In addition, artificial materials such as plastic pieces and feedstuffs were recorded. The occurrences of artificial materials and feedstuffs should be concerned in the conservation of the Okinawa rail.

2009年および2012–2015年に沖縄島北部においてルートセンサス法により観察されたケナガネズミ

谷口祥平, 平城達哉, 小林 峻, 伊澤雅子

沖縄生物学会誌   57   243 - 251   2019年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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The Ryukyu long-furred rat Diplothrix legata is endemic to the Ryukyu Archipelago. The present study aimed to obtain basic ecological information of this species on Okinawa-jima Island. Route census surveys were conducted along paved roads in the northern part of Okinawa-jima Island from June to December 2009, and from April 2012 to December 2015. Although the rats were observed throughout the year, there seems to be a possible tendency that they were observed more frequently during the reproductive season. However, due to limited sample sizes, it is necessary to reevaluate the seasonal variation in the number of individuals observed on the road. All observations of multiple individuals at one time occurred from September to December, and juveniles were observed only in December. Potential predators, such as invasive carnivores (cats, dogs, and mongooses), owls, and snakes, were also observed. It is necessary to take further actions to remove alien predators and to construct the measures against the traffic accidents by taking into account the occurring environments and seasons.

The pollination system of the widely distributed mammal-pollinated Mucuna macrocarpa (Fabaceae) in the tropics.

Kobayashi S, Denda T, Placksanoi J, Waengsothorn S, Aryuthaka C, Panha S, Izawa M

Ecology and evolution ( Ecology and Evolution )  9 ( 11 ) 6276 - 6286   2019年06月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Although the pollinators of some plant species differ across regions, only a few mammal‐pollinated plant species have regional pollinator differences in Asia. Mucuna macrocarpa (Fabaceae) is pollinated by squirrels, flying foxes, and macaques in subtropical and temperate islands. In this study, the pollination system of M. macrocarpa was identified in tropical Asia, where the genus originally diversified. This species requires “explosive opening” of the flower, where the wing petals must be pressed down and the banner petal pushed upward to fully expose the stamens and pistil. A bagging experiment showed that fruits did not develop in inflorescences (n = 66) with unopened flowers, whereas fruits developed in 68.7% of inflorescences (n = 131) with opened flowers. This indicated that the explosive opening is needed for the species to reproduce. Four potential pollinator mammals were identified by a video cameratrap survey, and 78.3% and 60.1% of monitored inflorescences (n = 138) were opened by gray‐bellied squirrels (Callosciurus caniceps) and Finlayson's squirrels (C. finlaysonii), respectively, even though more than 10 mammal species visited flowers. Nectar was surrounded by the calyx, and the volume and sugar concentration of secreted nectar did not change during the day. This nectar secretion pattern is similar to those reported by previous studies in other regions. These results showed that the main pollinators of M. macrocarpa in the tropics are squirrels. However, the species' nectar secretion pattern is not specifically adapted to this particular pollinator. Pollinators of M. macrocarpa differ throughout the distribution range based on the fauna present, but there might not have been no distinctive changes in the attractive traits that accompanied these changes in pollinators.

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Civet pollination in Mucuna birdwoodiana (Fabaceae: Papilionoideae)

Shun Kobayashi, Gale Stephan, Tetsuo Denda, Masako Izawa

Plant Ecology ( Plant Ecology )  220 ( 4-5 ) 457 - 466   2019年05月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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Inferring pollinators from floral traits is problematic because many flowers do not conform to a prescribed phenotype by which they may be assigned to any one particular pollination ‘syndrome.’ This necessitates empirical investigation to confirm pollinator relationships. Mucuna birdwoodiana is thought to be fruit bat-pollinated on account of its malodorous, pale green, gullet-type flowers, but we sought to clarify its pollination system through direct examination. This study was conducted in Hong Kong. Flowers of this species undergo ‘‘explosive opening’’ during pollination. Bagging experiments were conducted to check the necessity of this mechanism to achieve fruit set. Floral visitors were recorded by video camera traps and nectar secretion patterns were surveyed. Flowers do not open automatically and unopened flowers do not fructify. Masked palm civets, Paguma larvata, and introduced Pallas’s squirrels, Callosciurus erythraeus styani, were observed opening flowers, and fruits were found to form on flowers opened by both species. Paguma larvata opened flowers more frequently and less destructively than C. e. styani. The nectar is sucrose-dominant with no variation in nectar volume nor sugar concentration throughout the day. Pollination success in M. birdwoodiana is dependent on flower-opening animals. The primary pollinator of M. birdwoodiana is P. larvata, not fruit bats as had been suggested by a suite of supposedly adaptive floral traits.

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Seed feeding behavior of Diplothrix legata (Muridae: Rodentia): Effects on germination of five plants in Okinawajima Island, Japan

Reina Nago, Shun Kobayashi, Teruo Kinjo, Kozue Ogimi, Akari Shinjo, Shinobu Namisato, Anna Futamatagawa, Genwa Higa, Masako Izawa

Mammal Study ( Mammal Study )  44 ( 2 ) 129 - 134   2019年04月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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This study examined how seed feeding by the Ryukyu long-furred rat Diplothrix legata affects germination of five plants (Cerasus campanulata, Actinidia rufa, Ficus erecta, Oreocnide pedunculata, and Melastoma candidum) in Okinawajima Island, Japan. The germination rates of seeds from fresh fruit and fecal pellets of two captive rats, as well as the feeding behaviors, were observed. Most of C. campanulata seeds, which were the largest among the five plant species, were crushed by rats. Seeds of the other four plants were swallowed whole; however, the excretion rates were low (< 20%). The germination rates of A. rufa, F. erecta, and M. candidum from fecal pellets were significantly lower than that of seeds from fresh fruits. The rats showed a higher excretion rate for the seeds of O. pedunculata, and the excreted seeds showed a similar germination rate to that of seeds from fresh fruits, which might be attributed to the small-sized seeds with hard coats. Some fruits of A. rufa and F. erecta were dropped before they were completely consumed. Thus, undigested seeds and dropped seeds might be dispersed by D. legata, although this species should be regarded mainly as a seed predator.

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Resource use among sympatric Callosciurus spp. (Sciuridae) in tropical seasonal forests during the dry season in northeastern Thailand

Shun Kobayashi, Jumlong Placksanoi, Artchawakom Taksin, Chittima Aryuthaka, Tetsuo Denda, Masako Izawa

Mammal Study ( Mammalogical Society of Japan )  44 ( 1 ) 23 - 32   2018年11月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Southeast Asia contains a diverse array of squirrels, with several species living sympatrically. However, limited data are available on how the squirrels coexist and share resources in the same habitat. Here, we examined resource-use variation between sympatric Callosciurus finlaysonii and C. caniceps in two habitats of northeastern Thailand: dry dipterocarp forest (DDF) and dry evergreen forest (DEF). Both species were bimodally crepuscular and did not differ in daily activity patterns. Callosciurus caniceps was fewer in number than C. finlaysonii in DDF, but they had similar frequencies in DEF. The two species generally consumed different plant species, though some preferred fruits overlapped. Callosciurus finlaysonii from DEF remained higher in the trees than C. caniceps; all nests at elevated locations belonged to C. finlaysonii. When feeding, the preferred height of both species varied depending on food availability. In DEF, C. caniceps dominated C. finlaysonii during interactions. Together, our observations indicate that sympatry is possible because the two species differ in food choice and/or engage in vertical zonation.

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Who can open the flower? Assessment of the flower opening force of mammal-pollinated Mucuna macrocarpa

Shun Kobayashi, Euichi Hirose, Tetsuo Denda, Masako Izawa

Plant Species Biology ( Wiley )  33 ( 4 ) 312 - 316   2018年10月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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Effective pollinators in Fabaceae species with papillionaceous flowers should have sufficient force to open the petals and expose the stamens and pistils from the keel petals. Here, we assessed the force that is required (operative force) to open the petals of the mammal-pollinated Mucuna macrocarpa, in parallel with estimating the force of bee species. The operative force of M. macrocarpa was quantified by a digital force gauge and the force of three bee species that frequent these flowers was estimated from body mass. The operative force was 1.635±0.146 (mean±SD) newton (N). This force was far larger than that estimated for the largest bee in the study area. In addition, the operative force of M. macrocarpa was 16–409 times greater than that of bee-pollinated plants. Our results demonstrate that the operative force of M. macrocarpa flowers is adapted to mammalian openers, preventing potential nectar robbers.

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Comparison of visitors and pollinators of Mucuna macrocarpa between urban and forest environments

Kobayashi S, Denda T, Liao C.-C, Lin Y.-H, Liu W.-T, Izawa M

Mammal Study ( Mammal Study )  43 ( 4 ) 219 - 228   2018年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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Mammal-plant interactions differ significantly between urban and natural environments; however, knowledge of mammal-pollinated plants in urban areas remains limited compared to plants in their natural habitats. Here, we compared the flower visitors of Mucuna macrocarpa between urban and forested areas in Okinawa-jima Island, Japan and in Taiwan. Mucuna macrocarpa requires a highly specialized pollination process. Our study showed that Ryukyu flying foxes (Pteropus dasymallus) were the pollinator of M. macrocarpa in both the urban and forested areas of Okinawa-jima Island, whereas, in Taiwan, red-bellied squirrels (Callosciurus erythraeus) were the main pollinator species. Both pollinator species visited inflorescences in urban areas at the same or higher frequency as in forested areas. In contrast, non-pollinating animals engaged in nectar-robbing or picking-off behaviors when visiting Mucuna flowers in forested areas only. These results suggest that M. macrocarpa successfully attracts local pollinators, even in urban environments that have relatively low biodiversity. The negative effect of animal guilds on the success of M. macrocarpa pollination is significantly lower in urban compared to forested areas. However, the fragmentation caused by urbanization might reduce the opportunity for cross-pollination.

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外来種ゲットウトゲムネサルゾウムシXenysmoderes consularis (コウチュウ目ゾウムシ科) の西表島および竹富島における生息確認と分布状況

小林峻, 伊澤雅子

Fauna Ryukyuana   45   15 - 17   2018年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

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An exotic weevil Xenysmoderes consularis was recorded in 2018 for the first time from Iriomote-jima and Taketomi-jima Islands, Yaeyama Group, Ryukyu Archipelago, Japan. The occurrence of this species on both islands had not been confirmed by our previous surveys in 2011 on Iriomote-jima Island and in 2010 on Taketomi-jima Island, respectively. This species might be introduced from Ishigaki-jima or Okinawa-jima Island.

Regional differences in mammalian pollinators of Mucuna macrocarpa (Leguminosae): a review

Shun Kobayashi, Tetsuo Denda, Chi-Cheng Liao, Jumlong Placksanoi, Surachit Waengsothorn, Chittima Aryuthaka, Somsak Pnaha, Masako Izawa

Tropical Natural History   8 ( 2 ) 135 - 146   2018年09月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

Floral traits of mammal-pollinated Mucuna macrocarpa (Fabaceae): Implications for generalist-like pollination systems.

Kobayashi S, Denda T, Liao CC, Lin YH, Wu SH, Izawa M

Ecology and evolution ( Wiley )  8 ( 16 ) 8607 - 8615   2018年08月 [ 査読有り ]

掲載種別: 研究論文（学術雑誌）

　概要を見る

Floral traits are adapted by plants to attract pollinators. Some of those plants that have different pollinators in different regions adapt to each pollinator in each region to maximize their pollination success. Mucuna macrocarpa (Fabaceae) limits the pollinators using its floral structure and is pollinated by different mammals in different regions. Here, we examine the relationships between floral traits of M. macrocarpa and the external morphology of mammalian pollinators in different regions of its distribution. Field surveys were conducted on Kyushu and Okinawajima Island in Japan, and in Taiwan, where the main pollinators are the Japanese macaque Macaca fuscata, Ryukyu flying fox Pteropus dasymallus, and red-bellied squirrel Callosciurus erythraeus, respectively. We measured the floral shapes, nectar secretion patterns, sugar components, and external morphology of the pollinators. Results showed that floral shape was slightly different among regions and that flower sizes were not correlated with the external morphology of the pollinators. Volume and sugar rate of nectar were not significantly different among the three regions and did not change throughout the day in any of the regions. However, nectar concentration was higher in Kyushu than in the other two regions. These results suggest that the floral traits of M. macrocarpa are not adapted to each pollinator in each region. Although this plant limits the number of pollinators using its flower structure, it has not adapted to specific mammals and may attract several species of mammals. Such generalist-like pollination system might have evolved in the Old World.

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