研究者総覧

畑 啓生 (ハタ ヒロキ)

  • 大学院理工学研究科 環境機能科学専攻 助教
Last Updated :2020/11/10

研究者情報

学位

  • 博士(人間・環境学)(京都大学)

ホームページURL

J-Global ID

研究キーワード

  • 魚   種間関係   生態学   

研究分野

  • ライフサイエンス / 生態学、環境学

経歴

  • 2016年07月 - 現在  愛媛大学大学院理工学研究科准教授
  • 2010年04月 - 2016年06月  愛媛大学大学院理工学研究科助教
  • 2008年 - 2010年  近畿大学農学部Faculty of Agriculture講師
  • 2005年 - 2008年  京都大学大学院理学研究科日本学術振興会PD
  • 2004年 - 2005年  京都大学大学院人間・環境学研究科日本学術振興会PD

学歴

  • 2001年04月 - 2004年03月   京都大学   人間・環境学研究科   相関環境学専攻
  • 1999年04月 - 2001年03月   東北大学   大学院理学研究科   生命科学研究科
  • 1995年04月 - 1999年03月   京都大学   総合人間学部   自然環境学科

所属学協会

  • 日本魚類学会   日本進化学会   日本生態学会   International Studies for Reef Studies   

研究活動情報

論文

  • Hiroki Hata, Yohsuke Uemura, Kaito Ouchi
    Freshwater Biology 2020年10月 [査読有り]
     研究論文(学術雑誌)
  • Hiroki Hata, Shota Takano, Hiroyuki Masuhara
    Scientific Reports 10 1 2020年09月 [査読有り]
     研究論文(学術雑誌) 
    Abstract Turf algae become the most abundant benthic group on coral reefs after mass coral bleaching. By defending feeding territories, damselfishes enhance the growth of turf algae in so-called algal farms and affect coral communities both directly and indirectly. We found several white scars (i.e., bite lesions) on massive Porites colonies around feeding territories. In this study, we examined the occurrence of white scars on corals and their function in coral–algal competition at the boundaries between algal farms of two damselfish speciesthe intensive farmer Stegastes nigricans, and the intermediate farmer S. lividus—and adjacent Porites corals for 3 years around Okinawa Island, Japan. White scars occurred on Porites colonies only adjacent to the territories of both damselfish species. Of the white scars on corals around S. nigricans territories, 73% of the area was covered by algae within 2 weeks, while the remaining was re-covered by Porites tissues. The coral–algal boundaries encroached further into areas of coral when the area of white scars were larger. These results suggest that both intensive and intermediate farmers bite adjacent Porites colonies causing white scars on corals, and expand their territories onto corals using algae-covered white scars as stepping stones.
  • R. Kawanishi, N. Kohya, A. Sogabe, H. Hata
    Parasitology International 72 101932 - 101932 2019年10月 [査読有り]
     研究論文(学術雑誌)
  • HATA Hiroki, UEMURA Yohsuke, OUCHI Kaito, MATSUBA Hideki
    PLOS ONE 14 2 e0212452  2019年02月 [査読有り]
     研究論文(学術雑誌)
  • Takeuchi Y, Hata H, Maruyama A, Yamada T, Nishikawa T, Fukui M, Zatha R, Rusuwa B, Oda Y
    The Journal of experimental biology 222 3 1 - 9 2019年02月 [査読有り]
  • Uemura Yohsuke, Yoshimi Shotaro, HATA Hiroki
    PLOS ONE 13 9 e0203423  2018年09月 [査読有り]
     研究論文(学術雑誌)
  • 高緯度サンゴ群集域におけるコジリサンゴガニ属2種の記録
    平林 勲, 畑 啓生
    南紀生物 60 1 42 - 47 2018年06月 [査読有り]
     研究論文(学術雑誌)
  • 愛媛県松山平野における湧水性水域へのマツカサガイの試験的導入
    吉見 翔太郎, 井上 幹生, 畑 啓生
    保全生態学研究 23 99 - 114 2018年06月 [査読有り]
     研究論文(学術雑誌)
  • Michio Hori, Mifuyu Nakajima, Hiroki Hata, Masaki Yasugi, Satoshi Takahashi, Masanori Nakae, Kosaku Yamaoka, Masanori Kohda, Jyun-ichi Kitamura, Masayoshi Maehata, Hirokazu Tanaka, Norihiro Okada, Yuichi Takeuchi
    ZOOLOGICAL SCIENCE 34 4 267 - 274 2017年08月 [査読有り]
     研究論文(学術雑誌) 
    Laterality has been studied in several vertebrates, mainly in terms of brain lateralization and behavioral laterality, but morphological asymmetry has not been extensively investigated. Asymmetry in fishes was first described in scale-eating cichlids from Lake Tanganyika, in the form of bilateral dimorphism in which some individuals, when opening their mouths, twist them to the right and others to the left. This asymmetry has a genetic basis, and is correlated with lateralized attack behaviors. This has subsequently been found in fishes from numerous taxa with various feeding habits. The generality of such morphological laterality should thus be investigated in as wide a range of fishes as possible. Using specific indicators of lateral differences in mandibles and head inclination, we find that representative species from all 60 orders of extant gnathostome fishes (both bony and cartilaginous) possess morphological laterality. Furthermore, we identify the same laterality in agnathans (hagfish and lamprey), suggesting that this trait appeared early in fish evolution and has been maintained across fish lineages. However, a comparison of asymmetry among groups of bony fishes reveals, unexpectedly, that phylogenetically more recent-groups possess less asymmetry in body structures. The universality of laterality in fishes indicates a monophyletic origin, and may have been present in the ancestors of vertebrates. Ecological factors, predatorprey interactions in particular, may be key drivers in the evolution and maintenance of dimorphism, and may also be responsible for the cryptic trend of asymmetry in derived groups. Because lung-fish and coelacanths share this trait, it is likely that tetrapods also inherited it. We believe that study of this morphological laterality will provide insights into the behavioral and sensory lateralization of vertebrates.
  • 桑原明大, 松葉成生, 井上幹生, 畑啓生
    保全生態学研究 22 1 91‐103  2017年05月
  • Hiroki Hata, Atsushi Sogabe, Shinya Tada, Ryohei Nishimoto, Reina Nakano, Nobuhiko Kohya, Hirohiko Takeshima, Ryota Kawanishi
    MARINE BIOLOGY 164 5 2017年05月 [査読有り]
     研究論文(学術雑誌) 
    In host-parasite coevolution, parasite innovations including the acquisition of new habitats and novel traits can trigger evolutionary breakthroughs and enhance parasite diversification via accumulation of new hosts. All species of the family Cymothoidae are obligate fish parasites, attaching to exterior body surfaces of fish, the buccal or opercular cavities, or burrowing into abdominal muscle tissue. In the present study, we constructed a molecular phylogeny of 27 cymothoid species that parasitise 38 fish species, combined with 2 prior cymothoid datasets, based on the sequences of mitochondrial 16S rRNA and COI genes. We explored the evolution of the host attachment mode, and the habitat shift from saline water to freshwater. Our evolutionary trees include two freshwater clades, an abdominal burrower clade, and cymothoid clades that are closer to the base of Cymothoidae than those initially analysed. We found that the basal clade of Cymothoidae was Elthusa sacciger, which is parasitic in the opercular cavity of synaphobranchid eels. This result suggests that cymothoids may have originated in deep seas, subsequently expanded to shallow seas, and then to brackish and/or freshwater, by shifting host species. Invasion of freshwater habitats has occurred at least twice; freshwater abdominal muscle burrowers living on armoured catfish constitute a clade allied to E. sacciger. The ancestral host attachment site, based on our dataset, was the opercular cavity, followed (sequentially) by buccal colonisation and attachment to the external body.
  • Shinya Tada, Michio Hori, Kosaku Yamaoka, Hiroki Hata
    HYDROBIOLOGIA 791 1 83 - 101 2017年05月 [査読有り]
     研究論文(学術雑誌) 
    In Lake Tanganyika, several lineages of cichlids have diversified into 200 species. Tribe Tropheini contains the greatest richness of herbivorous species that are classified into four ecomorphs: grazers, browsers, suckers, and pickers. All of these ecomorphs coexist on littoral rocky shores. To reveal the differences among species within ecomorphs, we analysed fish shape and functional morphology related to feeding habits, using geometric morphometrics, and measured intestine length. Furthermore, we tested the relationship between genetic and morphological distances. As a result, diversities of functional morphology among ecomorphs, and among species within ecomorphs, were revealed. In grazers, morphological diversity was greatest in jaws and the opening direction of mouth, suggesting that these species have adapted to feed on various substrata. In browsers, intestine length varied among species, indicating that this ecomorph consists of species with various specializations in herbivory. Morphological divergence was found only in the mandible and occlusal facet in grazers. No clear relation was found between morphological and phylogenetic distances in browsers, which are a polyphyletic group, indicating that their traits were acquired by convergence in multiple lineages. Our data suggest that the observed morphological variation among species enable sympatric species to separate their feeding niches.
  • Haruki Ochi, Satoshi Awata, Hiroki Hata, Masanori Kohda
    HYDROBIOLOGIA 791 1 103 - 114 2017年05月 [査読有り]
     研究論文(学術雑誌) 
    Animals in a population consistently differ from one another in behavioural types over time and this difference can affect intra- and interspecific relationships. However, empirical studies about roles of behavioural individual variation in interspecific interactions are scarce. Here, we provide evidence that inter-individual variation of a cichlid in aggression affects access to its territory by a heterospecific cichlid. In Lake Tanganyika, a zoobenthivorous cichlid Neolamprologus mustax (Nm) is admitted into territories of an algivorous Variabilichromis moorii (Vm) to prey on benthic invertebrates, while other zoobenthivorous fishes are chased from the territories. We conducted an experiment in which caged Nm fish were exposed twice to each Vm fish in natural habitats. Results indicated repeatable individual variations in Vm aggression towards Nm. Moreover, diving observations indicated that Nm fish frequently used some of Vm territories inside their own territories, but rarely or never used others. This uneven use of Vm territories by the Nm fish was negatively correlated with individual variations in Vm aggression. We conclude that the preferential access of Nm to Vm territory is gained by Nm's recognising more tolerant Vm fish or discriminating among sites for their territories.
  • Momoko Igawa, Hiroki Hata, Makoto Kato
    PLOS ONE 12 1 e0169825  2017年01月 [査読有り]
     研究論文(学術雑誌) 
    Solitary scleractinian corals of the genera Heterocyathus and Heteropsammia inhabit soft marine bottoms without attaching to hard substrata. The corallums of these genera contain a coiled cavity inhabited by a sipunculan that roams the seafloor, carrying the host coral with it. The coral serves as a sturdy shelter that protects the sipunculan from possible predators. At the same time, the sipunculan maintains the coral in an upright position on the soft bottom. This coral-sipunculan association is unique because two phylogenetically distant coral genera have developed convergent associations with sipunculans. We investigate the process of convergent evolution of two coral species, Hc. aequicostatus and Hp. cochlea, in Okinawa, Japan, with their symbiotic sipunculans, using phylogenetic and morphological analyses. Phylogenetic analyses clarified that the symbiotic sipunculans comprise two distinct clades, surprisingly both of which are associated with both coral species. The bodily habitus of the sipunculan differed between coral species and fit the morphologies of the coiled cavities of their respective host corals. Our results suggest that the two coral species share two sipunculan clades and that sipunculan morphology is plastic and determined by the internal structure of their host corals.
  • R. Abila, P. Akoll, C. Albertson, D. Antunes, T. Banda, R. Bills, A. Bulirani, A. Chocha Manda, A. S. Cohen, F. Cunha-Saraiva, S. Derycke, I. Donohue, M. Du, A. M. Dudu, B. Egger, K. Fritzsche, J. G. Frommen, H. F. Gante, M. J. Genner, A. Haerer, H. Hata, K. Irvine, P. Isumbisho Mwapu, L. Janssens de Bisthoven, A. Jungwirth, P. Kaleme, C. Katongo, L. Kever, S. Koblmueller, A. Konings, A. Lamboj, F. Lemmel-Schaedelin, G. Machado Schiaffino, K. Martens, P. Masilya Mulungula, A. Meyer, H. L. More, Z. Musilova, F. Muterezi Bukinga, R. Muzumani, G. Ntakimazi, W. Okello, H. Phiri, L. Pialek, P. D. Plisnier, J. A. M. Raeymaekers, J. Rajkov, O. Rican, R. Roberts, W. Salzburger, I. Schoen, K. M. Sefc, P. Singh, P. Skelton, J. Snoeks, K. Schneider, C. Sturmbauer, H. Svardal, O. Svensson, J. Torres Dowdall, G. F. Turner, A. Tyers, J. C. van Rijssel, M. Van Steenberge, M. P. M. Vanhove, Erik Verheyen, A. -T. Weber, O. Weyl, A. Ziegelbecker, H. Zimmermann
    SCIENCE 354 6312 561 - 562 2016年11月 [査読有り]
  • R. Kawanishi, A. Sogabe, R. Nishimoto, H. Hata
    DISEASES OF AQUATIC ORGANISMS 122 1 13 - 19 2016年11月 [査読有り]
     研究論文(学術雑誌) 
    Cymothoid isopods (family Cymothoidae) are commonly found parasitizing diverse fishes, including commercial species. However, the effects of these parasites on host body condition are still poorly known. Here we investigated the spatial variation of the effects of parasite infection on host body condition, using the parasitic load of the cymothoid Mothocya parvostis on the Japanese halfbeak Hyporhamphus sajori at 4 sampling sites in western Japan. M. parvostis prevalence at each site (41.6-74.4%) was higher than that known for other fish host-cymothoid systems (usually less than 30%). The number of isopods in infected hosts, the reproductive status of female isopods (i.e. ovigerous/non-ovigerous), and the body size of female and male isopods relative to the size of their hosts were not significantly different among sites. However, at the site where human activity was most intense, M. parvostis infection had a significantly negative effect on host body condition. These results suggest that the effect of cymothoid infection on host body condition might be benign under natural conditions but becomes detrimental in habitats that are unsuitable for the host, such as highly human-impacted areas.
  • Hiroki Hata, Haruki Ochi
    ROYAL SOCIETY OPEN SCIENCE 3 11 2016年11月 [査読有り]
     研究論文(学術雑誌) 
    Cichlid fish in Lake Tanganyika represent a system of adaptive radiation in which eight ancestral lineages have diversified into hundreds of species through adaptation to various niches. However, Tanganyikan cichlids have been thought to be oversaturated, that is, the species number exceeds the number of niches and ecologically equivalent and competitively even species coexist. However, recent studies have shed light on niche segregation on a finer scale among apparently equivalent species. We observed depth and substratum preferences of 15 herbivorous cichlids from four ecomorphs (i.e. grazer, browser, scraper and scooper) on a rocky littoral slope for 14 years. Depth differentiation was detected among grazers that defended feeding territories and among browsers with feeding territories. Cichlid species having no feeding territory also showed specificity on depth and substratum, resulting in habitat segregation among species that belong to the same ecomorph. Phylogenetically close species did not occupy adjacent depths, nor the opposite depth zones. Our findings suggest that apparently equivalent species of the same ecomorph coexist parapatrically along depth on a few-metre scale, or coexist with different substratum preferences on the rocky shore, and this niche segregation may have been acquired by competition between encountering equivalent species through repetitive lake-level fluctuations.
  • Hata H, Shibata J, Omori K, Kohda M, Hori M
    Zoological letters 1 15  2015年05月 [査読有り]
  • 松葉成生, 吉見翔太郎, 井上幹生, 畑啓生
    魚類学雑誌 61 2 89 - 96 2014年11月
  • Hiroki Hata, Akifumi S. Tanabe, Satoshi Yamamoto, Hirokazu Toju, Masanori Kohda, Michio Hori
    BMC BIOLOGY 12 90  2014年11月 [査読有り]
     研究論文(学術雑誌) 
    Background: Lake Tanganyika, an ancient lake in the Great Rift Valley, is famous for the adaptive radiation of cichlids. Five tribes of the Cichlidae family have acquired herbivory, with five ecomorphs: grazers, browsers, scrapers, biters and scoopers. Sixteen species of the herbivorous cichlids coexist on a rocky littoral slope in the lake. Seven of them individually defend feeding territories against intruding herbivores to establish algal farms. We collected epiphyton from these territories at various depths and also gathered fish specimens. Algal and cyanobacteria community structures were analysed using the amplicon-metagenomic method. Results: Based on 454-pyrosequencing of SSU rRNA gene sequences, we identified 300 phototrophic taxa, including 197 cyanobacteria, 57 bacillariophytes, and 31 chlorophytes. Algal farms differed significantly in their composition among cichlid species, even in the same ecomorph, due in part to their habitat-depth segregation. The algal species composition of the stomach contents and algal farms of each species differed, suggesting that cichlids selectively harvest their farms. The stomach contents were highly diverse, even between species in the same tribe, in the same feeding ecomorph. Conclusions: In this study, the amplicon-metagenomic approach revealed food niche separation based on habitat-depth segregation among coexisting herbivorous cichlids in the same ecomorphs in Lake Tanganyika.
  • Hiroki Hata, Masaki Yasugi, Yuichi Takeuchi, Satoshi Takahashi, Michio Hori
    Ecology and Evolution 3 14 4641 - 4647 2013年11月 [査読有り]
     研究論文(学術雑誌) 
    The left-right asymmetry of scale-eating Tanganyikan cichlids is described as a unilateral topographical shift of the quadratomandibular joints. This morphological laterality has a genetic basis and has therefore been used as a model for studying negative frequency-dependent selection and the resulting oscillation in frequencies of two genotypes, lefty and righty, in a population. This study aims were to confirm this laterality in Perissodus microlepis Boulenger and P. straeleni (Poll) and evaluate an appropriate method for measuring and testing the asymmetry. Left-right differences in the height of the mandible posterior ends (HMPE) and the angle between the neurocranium and vertebrae of P. microlepis and P. straeleni were measured on skeletal specimens. Snout-bending angle was also measured using a dorsal image of the same individuals following a previous method. To define which distribution model, fluctuating asymmetry (FA), directional asymmetry (DA), or antisymmetry (AS), best fit to the lateral asymmetry of the traits, we provided an R package, IASD. As a result, HMPE and neurocranium-vertebrae angle of both species were best fitted to AS, suggesting that P. microlepis and P. straeleni showed a distinct dimorphism in these traits, although snout-bending angle of P. microlepis was best fitted to FA. Measurement error was low for HMPE comparing the snout-bending angle in P. microlepis, indicating that measuring HMPE is a more accurate method. The scale-eating tribe Perissodini showed distinct antisymmetry in the jaw skeleton and neurocranium-vertebrae angle, and this laterality remains a valid marker for further evolutionary studies. © 2013 The Authors.
  • 畑啓生
    科学 83 7 0796 - 0797 2013年07月
  • Hiroki Hata, Isao Hirabayashi, Hideki Hamaoka, Yoshio Mukai, Koji Omori, Hironobu Fukami
    MARINE ENVIRONMENTAL RESEARCH 85 45 - 53 2013年04月 [査読有り]
     研究論文(学術雑誌) 
    Tuna-farming is expanding worldwide, necessitating the monitoring/managing of its effects on the natural environment. In Japan, tuna-farming is conducted on coral reefs that have been damaged by mass-bleaching events and crown-of-thorns starfish (COTS) outbreaks. This study focused on the coral community on an artificial substrate of tuna-farm to reveal the possible effects of tuna-farming on the natural environment. Corals flourished on ropes suspended in the farm in the Amami Islands, southern Japan. These were moored 3 m below the sea-surface in 50-m-deep water. The coral community on the rope was analyzed and compared with those on natural substrata on two adjacent COTS-damaged reefs and with that in a protected reef. Corals were monitored throughout a year. Sixty coral species grew on the ropes, that corresponds to 27.3% of the 220 species known from Amami. The coral community was unique, dominated by massive faviid corals. On the ropes, the water temperature rarely exceeded 30.0 degrees C and no corals on the rope were severely bleached or covered by sedimentation during the observations. The tuna-farm infrastructure provided corals with a suitable habitat, and species-rich coral communities were established. These coral communities are an important node connecting tuna-farms and the natural environment. (C) 2012 Elsevier Ltd. All rights reserved.
  • Arno Germond, Hiroki Hata, Yoshiyuki Fujikawa, Toshiyuki Nakajima
    European Journal of Phycology 48 4 485 - 496 2013年 研究論文(学術雑誌) 
    Recent phylogenetic studies of Chlorella-like algae revealed that this group has diversified into free-living and endosymbiotic niches, the latter within protists and invertebrate organisms. Our previous studies using a long-term culture composed of an alga (Chlorella vulgaris, rDNA sequence unknown), a bacterium (Escherichia coli) and a ciliate (Tetrahymena thermophila), suggested that some clones in the algal population developed an endosymbiotic ability with T. thermophila while others developed an ectosymbiotic ability with E. coli from a non-associated stage. In this paper, an rDNA (18S, ITS1, 5.8S, ITS2)-based phylogeny of the ancestral strain and derived clones isolated from 5-year microcosm cultures was constructed and revealed that the alga belongs to the genus Micractinium. This result was supported by analysis of the secondary structure of the rRNA gene. No difference was observed in the sequence between the ancestral and derived clones. On the other hand, some morphological and physiological traits of the ancestral strain and the derived clones were analysed and revealed that several phenotypic changes had occurred among the algal clones. In particular, the derived clones obtained from long-term cultures had increased in cell size, changed in their ability to grow at pH 4.0, and developed a tendency for cell-aggregation or sedimentation. © 2013 © British Phycological Society.
  • Koji Omori, Hidejiro Ohnishi, Hideki Hamaoka, Tadao Kunihiro, Sayaka Ito, Michinobu Kuwae, Hiroki Hata, Todd W. Miller, Keiichiro Iguchi
    ECOLOGICAL MODELLING 243 89 - 94 2012年09月 研究論文(学術雑誌) 
    We present a mathematical model of the maintenance of polymorphism of fluvial and amphidromous types in a fish population. Downstream drifting of offspring after hatching and their subsequent upstream migration have an important effect on the maintenance of an upstream population. This model, which assumes a linear relationship of offspring mortality rate, nutritional conditions, and flow rate or inclination with the distance from the river mouth, enables us to calculate the number of recruits to the mother population. From the present analysis, we can predict that the fluvial type producing large embryos is selected in the upper reaches under conditions where there are large differences in offspring mortality and flow rate between the upper and lower reaches, and a small difference in nutritional conditions between these sites. Therefore, the fluvial type can be more easily evolved in tropical regions than temperate regions where the difference in nutritional conditions is relatively larger. This selection is promoted when offspring mortality decreases greatly with their size. Conversely, at the lower reaches of the same river, the amphidromous type producing many small embryos is favored. These two populations can be the polymorphism of a single population species in a river, and can be established as different species in terms of pre- or post-reproductive isolation mechanisms, such as assortative mating or habitat preference, even if their members mate with each other in a river. We can assert that sympatric speciation is common in fluvial environments, when this process really works, because other taxonomic groups, such as Annelida. Crustacea, and Mollusca, also have the same sympatric pair of fluvial and amphidromous species derived from marine origin, that is, so called the evolutionary invasion from marine to terrestrial environments. (C) 2012 Elsevier B.V. All rights reserved.
  • Hiroki Hata, Rieko Takahashi, Hiroshi Ashiwa, Satoshi Awata, Tomohiro Takeyama, Masanori Kohda, Michio Hori
    ZOOLOGICAL SCIENCE 29 1 49 - 53 2012年01月 [査読有り]
     研究論文(学術雑誌) 
    The asymmetry of mouth morphology, in which the mouth opens either leftward or rightward, is a unique example of antisymmetry that is widely found in fishes, such as Tanganyikan scale-eating cichlids, herbivorous cichlids, and the Japanese freshwater goby. This dimorphism is thought to be heritable in a Mendelian manner similar to that of the dominance of the lefty allele over righty, with homozygotes of lefty alleles being absent. This study aims to reveal whether this trait is inherited in the same Mendelian manner in fishes other than those examined to date, and whether the absence of the dominant homozygote is due to a lethal effect. We conducted F-1 and F-2 breeding experiments using the Tanganyikan cichlid Julidochromis transcriptus and Japanese medaka Oryzias latipes. For both J. transcriptus and O. latipes, the F1 generations produced by incrossing lefty parents showed a lefty: righty ratio of 2:1, whereas incrosses of righties produced only righty offspring. Test crosses between lefty and righty produced a 1:1 ratio of lefty and righty offspring. These results are consistent with the inheritance model in which righty is homozygous for a recessive righty allele and lefty is heterozygous for dominant lefty and recessive righty alleles, in agreement with previous observations. The F-2 test cross also confirmed this pattern. Furthermore, no lethal effects on hatchability of O. latipes were detected, refuting the suggestion that the dominant homozygote is embryonic lethal. We conclude that mouth laterality is inherited in the same Mendelian manner in these two species, similar to that other fish species studied previously. However, the reason for absence of the dominant homozygote remains unclear.
  • Hiroki Hata, Michio Hori
    LATERALITY 17 6 741 - 754 2012年 [査読有り]
     研究論文(学術雑誌) 
    The inheritance patterns of asymmetry in mouth opening in zebrafish were investigated using crossing experiments. Zebrafish exhibit asymmetric laterality in mouth opening, with each individual having either a leftward (righty) or rightward (lefty) bias. All righty incrosses produced only righty F-1, whereas all lefty incrosses resulted in an F-1 L:R ratio of 2:1. All test crosses between lefty and righty individuals resulted in an F-1 L:R = 1:1. These results were consistent with the hereditary pattern for Japanese medaka, three Tanganyikan cichlids, and a Japanese riverine goby. The pattern suggests a one-locus two-allele Mendelian model of inheritance, with the lefty allele being dominant over righty and the dominant homozygote being lethal. To determine the reason for the absence of lefty homozygotes, the survival rates of the offspring were examined according to developmental stage. Survival did not differ among combinations of parent laterality. Thus the mechanism underlying the lethality of the dominant homozygote remains unclear. This study showed that the mouth-opening laterality of zebrafish is genetically determined and that the direction follows a Mendelian inheritance pattern that is shared among cypriniform zebrafish, beloniform medaka, perciform cichlids, and a goby, suggesting a common genetic background in mouth-opening laterality among these species.
  • Hiroki Hata, Masaki Yasugi, Michio Hori
    PLOS ONE 6 12 e29349  2011年12月 [査読有り]
     研究論文(学術雑誌) 
    Background: Asymmetry in animal bodies and behavior has evolved several times, but our knowledge of their linkage is limited. Tanganyikan scale-eating cichlids have well-known antisymmetry in their bodies and behavior; individuals open their mouths leftward (righty) or rightward (lefty), and righties always attack the right flank of the prey, whereas lefties attack the left. This study analyzed the morphological asymmetry in a scale-eating characiform, Exodon paradoxus, and its behavioral handedness. Methodology/Principal Findings: Each eight E. paradoxus was observed for 1-h with a prey goldfish in an aquarium to detect the behavioral handedness. Following the experiment, the lateral differences in the mandibles and head-inclination of these eight and ten additional specimens were analyzed. Both measurements on the morphology showed a bimodal distribution, and the laterality identified by these two methods was always consistent within a given individual, indicating that the characin has morphological antisymmetry. Furthermore, this laterality significantly corresponded to behavioral handedness; that is, lefties more often rasped scales from the right flank of the prey and vice versa. However, the correlation between laterality and handedness is the opposite of that in the cichlids. This is due to differences in the feeding apparatus and technique. The characin has cuspids pointing forward on the external side of the premaxilla, and it thrusts its dominant body side outward from its body axis on the flank of the prey to tear off scales. By contrast, the cichlids draw their dominant body side inward toward the axis or rotate it to scrape or wrench off scales with the teeth lined in the opened mouth. Conclusions/Significance: This study demonstrated that the antisymmetry in external morphology and the corresponding behavioral handedness have evolved in two lineages of scale-eating fishes independently, and these fishes adopt different utilization of their body asymmetry to tear off scales.
  • Hiroki Hata, Yu Umezawa
    ECOLOGICAL RESEARCH 26 4 809 - 818 2011年07月 研究論文(学術雑誌) 
    The territorial damselfish, Stegastes nigricans, maintains algal farms by excluding invading herbivores and weeding unpalatable algae from its territories. In Okinawa, Japan, S. nigricans farms are exclusively dominated by Polysiphonia sp., a highly digestible filamentous rhodophyte. This study was aimed at determining the diet of S. nigricans in Okinawa and its dependency on these almost-monoculture algal farms based on stomach content and chemical analyses. Stomach content analyses revealed that all available food items in the algal farms (i.e., algae, benthic animal inhabitants, trapped detritus) were contained in fish stomachs, but amorphous organic matter accounted for 68% of the contents. Therefore, carbon and nitrogen stable isotope ratios and fatty acid (FA) compositions were analyzed to trace items actually assimilated in their bodies. Stable isotope analyses showed that benthic animals were an important food source even for this farmer fish. Two essential fatty acids (EFAs), 20:4n6 and 20:5n3, which are produced only by rhodophytes among available food items, were rich in the muscle tissue of S. nigricans as well as in algal mats and detritus, suggesting that algal mats contribute EFAs to S. nigricans directly and indirectly through the food web. In conclusion, S. nigricans ingested algal mats, detritus, and benthic animals maintained within its farm. Algae and detritus were original sources of EFAs, and benthic animals, which were much more abundant in the farms than in outside territories, provided a nitrogen-rich dietary source for the fish.
  • Hiroki Hata, Katsutoshi Watanabe, Makoto Kato
    BMC EVOLUTIONARY BIOLOGY 10 185  2010年06月 [査読有り]
     研究論文(学術雑誌) 
    Background: On coral reefs, damselfish defend their territories from invading herbivores and maintain algal turfs, from which they harvest filamentous algae. In southern Japan, intensive weeding of indigestible algae by Stegastes nigricans results in overgrowth by one filamentous alga, Polysiphonia sp. 1. Because this alga is highly susceptible to grazing and is competitively inferior to other algae, it survives only within the protective territories of this fish species, suggesting an obligate mutualism between damselfish and their cultivated alga. The wide distribution of damselfish species through the Indo-Central Pacific raises the question of whether this species-specific mutualism is maintained throughout the geographic range of the fish. To address this question, from all 18 damselfish species we conducted comprehensive surveys of algal flora within their territories throughout the Indo-West Pacific, and identified species of Polysiphonia using morphological examination and gene sequencing data. Results: Several species of the genus Polysiphonia were observed as a major crop in territories throughout the geographic range of S. nigricans. Polysiphonia sp. 1 occurred only in territories of S. nigricans in central areas of the Indo-Pacific. However, its occurrence was low from the Great Barrier Reef and Mauritius. In contrast, other indigenous Polysiphonia species, which formed a clade with Polysiphonia sp. 1, occurred in the territories of fishes from Egypt, Kenya, and the Maldives. The other Polysiphonia species in the clade only inhabited damselfish territories and were never found elsewhere. Conclusions: Cultivation mutualism between the damselfish S. nigricans and algae of Polysiphonia was maintained throughout the Indo-West Pacific, although algal crop species and the mode of cultivation (e.g., presence/absence of selective weeding, the species composition of algal turfs) varied among localities. This finding implies that damselfish utilize indigenous Polysiphonia species in newly colonized habitats in different ways, and therefore the algal composition and means of cultivation have diverged.
  • H. Ochi, H. Hata, M. Hori
    JOURNAL OF FISH BIOLOGY 71 2 399 - 410 2007年08月 研究論文(学術雑誌) 
    Underwater observations conducted in the shallow waters of the southern part of Lake Tanganyika showed that a zoobenthos-eating cichlid Neolamprologus mustax preferentially foraged in the permanent territory of an algivorous cichlid Neolamprologus moorii, even though other zoobenthos-eaters were chased out. Benthic invertebrates were much richer within the territory of N. moorii than outside, suggesting that the territory was an attractive feeding ground for zoobenthos-eaters. Stomach contents analysis showed that N. mustax rarely ate fish broods, although other zoobenthos-eaters often did so. It is concluded that the differential tolerance of N. moorii towards zoobenthos-eaters based on their harmfulness to broods benefits harmless N. mustax by allowing its use of the prey-rich territory. (c) 2007 The Authors Journal compilation (c) 2007 The Fisheries Society of the British Isles.
  • Hiroki Hata, Makoto Kato
    BIOLOGY LETTERS 2 4 593 - 596 2006年12月 [査読有り]
     研究論文(学術雑誌) 
    In cultivation mutualisms, farming animals prepare fields for cultivars, enhance their growth and harvest them. For example, in terrestrial ecosystems, plant-herbivore cultivation mutualisms arose between humans and their crops only relatively recently. We discovered an obligate cultivation mutualism between a damselfish and an alga in a coral reef ecosystem. The damselfish, Stegastes nigricans, manages algal farms through territorial defence against the invading grazers and through weeding of unpalatable algae. As a result, the algal farms of S. nigricans are dominated by one species, Polysiphonia sp. We performed an exhaustive survey of algal assemblages inside and outside the territories of five damselfish species around the Ryukyu Islands, Japan, using molecular and morphological characteristics. Polysiphonia sp. 1 grew exclusively inside the farms of S. nigricans, and never elsewhere. Since only Polysiphonia sp. 1 is harvested and consumed by the damselfish as a staple food, this interdependent relationship is an obligate cultivation mutualism. This is the first record of an obligate plant-herbivore cultivation mutualism in a marine ecosystem. Our data also suggest that three other Polysiphonia species are facultatively mutual with, commensal with, or parasitic on other damselfish species.
  • H Hata, M Kato
    JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY 313 2 285 - 296 2004年12月 研究論文(学術雑誌) 
    Algal farms maintained by different species of territorial herbivorous damselfishes vary in size, algal biomass, and species composition. To determine the factors that affect the structure of these farms, we compared fanning behavior and intensity between two sympatric damselfish species, Stegastes nigricans (Lacepede) and S. obreptus (Whitley), which maintain two different types of farms in the Okinawa Islands, southern Japan. By weeding of indigestible algae and prompt exclusion of herbivorous fishes and grazing sea urchins, S. nigricans manage relatively small farms largely dominated by one algal crop species, Polysiphonia sp. In contrast, by delayed exclusion of herbivores, S. obreptus maintain larger farms invaded by diverse indigestible algae, such as Chondria sp. and Padina sp. As a result of intensive management, S. nigricans attains a higher algal biomass per area than does S. obreptus. This study provides a new perspective, as it suggests that damselfishes practise both intensive and extensive fanning. The former results in small and highly productive monoculture farms of one palatable alga, while the latter leads to large, species-rich, mixed-culture farms. (C) 2004 Elsevier B.V. All rights reserved.
  • H Hata, M Kato
    MARINE ECOLOGY PROGRESS SERIES 263 159 - 167 2003年 研究論文(学術雑誌) 
    Resident herbivorous damselfishes exclude other herbivores from their territories and maintain dense stands of filamentous algae as algal farms. The damselfish Stegastes nigricans occupies coral reefs in the Okinawa Islands, southern Japan, and is unique in maintaining monocultural algal farms of the filamentous rhodophyte Polysiphonia sp. One of the mechanisms by which S. nigricans maintains these unique algal farms is by selective weeding of indigestible algae. This study tested the hypothesis that, were it not for management by S. nigricans, monocultures would be taken over by algal succession, even without grazing by other herbivores. We set up S. nigricans-exclusion cages inside and grazer-exclusion cages outside the territories of S. nigricans, and monitored algal succession. After exclusion of S. nigricans, the Polysiphonia sp. monoculture deteriorated rapidly and algal biomass decreased simultaneously. Filamentous rhodophytes replaced Polysiphonia sp. within 2 wk, and were in turn displaced by corticated macrophytes and calcareous algae (which are usually selectively weeded by S. nigricans). Monocultures of Polysiphonia sp. did not appear in the grazer-exclusion cages; pioneer Polysiphonia sp. colonized the areas just after caging, but thereafter was replaced by other filamentous rhodophytes, corticated macrophytes, and calcareous algae. Our experiments demonstrated that S. nigricans maintained monocultures and high biomass of palatable pioneer Polysiphonia sp. against algal succession by intensive farm-management, involving selective weeding.
  • H. Hata, H. Hata, M. Nishihira, S. Kamura
    Journal of Experimental Marine Biology and Ecology 280 1-2 95 - 116 2002年11月 研究論文(学術雑誌) 
    We compared the community structure of benthic algae inside and outside pomacentrid damselfish (Stegastes nigricans) territories in a moat at Sesoko Island, Okinawa, Japan. S. nigricans maintained "algae farms" that were dominated by the filamentous rhodophyte, Womersleyella setacea. Species richness and biomass were higher inside damselfish territories than outside, while species diversity and evenness were higher outside. Detrended correspondence analysis (DCA) based on species composition showed that the dominance of W. setacea was maintained throughout the year in all samples collected from inside damselfish territories. The observed strong dominance of filamentous rhodophytes was consistent with the findings of most studies on damselfish territories worldwide. However, the dominance of a single species of alga and low species diversity inside the territories was in contrast to the findings of previous studies, in which the reduction of grazing pressure caused intermediate disturbance and enhanced algal species diversity. This discrepancy in algal species diversity inside the damselfish territories seems to have been caused by unique characteristics of the alga and the fish. W. setacea traps sediment, which reduces the availability of firm substrata for attachment and inhibits the recruitment of some algae. Moreover, S. nigricans "weeds" indigestible calcareous and thicker algae. The algal assemblage outside damselfish territories varied among samples, and included mat-forming cyanophytes (Calothrix aeruginosa and Calothrix codicola), a prostrate laminar phaeophyte (Padina sp.), thin and small-scaled algae (Cladophora sp. and Feldmannia indica), finely branched filamentous rhodophytes (Taenioma perpusillum and Herposiphonia obscura), and a coarsely branched rhodophyte (Gelidiopsis variabilis). We placed artificial slate plates inside and outside damselfish territories, and showed that the W. setacea inside territories gradually increased in biomass, reaching the same levels of biomass and dominance as W. setacea on natural substrata. Outside the territories, the algal assemblage underwent succession from early colonizers, i.e., thin and small-scaled algae, to grazing-resistant algae such as mat-forming cyanophytes and prostrate laminar Padina sp. Under heavy grazing, the flora outside the territories was composed of early colonizers, grazing-resistant algae, and scattered erect algae that had probably escaped grazing by chance. Our findings suggest that sediment trapped by the turf of W. setacea inhibited recruitment of some algae, and that moderate cropping and selective weeding by S. nigricans excluded grazing-resistant algae and prevented early colonizers and competitively superior algae from out-competing W. setacea. Consequently, low species diversity and a high-biomass "farm" suitable for harvesting was maintained. © 2002 Elsevier Science B.V. All rights reserved.
  • H Hata, M Kato
    MARINE ECOLOGY PROGRESS SERIES 237 227 - 231 2002年07月 研究論文(学術雑誌) 
    Resident herbivorous damselfishes (Pisces: Pomacentridae) exclude other herbivores from their territories and reduce the grazing pressure within these territories. Among the damselfish, Stegastes nigricans is unique in that it manages a virtual monoculture dominated by the erect filamentous rhodophyte Womersleyella setacea, whereas many other herbivorous damselfishes maintain species-rich farms. We observed the behavior of S. nigricans in a lagoon in Okinawa, Japan, and discovered that this species intensively weeded out specific algae. To analyze weeding selectivity, we compared the algae picked up and discarded by S. nigricans to the algal assemblage found inside the territory. To examine the digestibility of each algal species, 10 damselfish were collected, and algae removed from their stomachs were compared with those found in the intestine and faeces. Inside their territories, S. nigricans selectively weeded out indigestible algae. These algae were late-colonizing Species, and the intensive weeding suppressed algal growth beyond early successional stages. Consequently, selective weeding enabled the fish to maintain virtual monocultural farms of a digestible early colonizer, W setacea, inside their territories.
  • H Hata, M Nishihira
    JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY 270 2 215 - 240 2002年04月 研究論文(学術雑誌) 
    The structures of benthic foraminiferal communities inside and outside the territory of the pomacentrid damselfish Stegastes nigricans on coral rocks in a moat of Sesoko Is. (26degrees38' N, 127degrees52' E) in Okinawa, Japan were compared. Inside the territory, an algal farm, i.e., a dense stand of a filamentous rhodophyte, Womersleyella setacea, was maintained throughout the year. Outside the territory, in areas subjected to intensive and continuous grazing by various grazers, the flora was composed of mat-like cyanophytes, a prostrate turf-form Padina sp., microscopically thin filaments and scattered filamentous rhodophytes. Algal biomass was greater inside the territory than outside the territory of the damselfish. These differences were reflected by the structure of the associated foraminiferal communities. We classified foraminiferal species based on their microhabitat use around algal communities into four life types: free-living type, crawling type, sedentary type, and sessile type, The abundance of foraminifera, especially the free-living type (e.g,, Peneroplis pertusus and Quinqueloculina seminulum) and sedentary type (Rosalina globularis and Cymbaloporetta squammosa), was greater inside the territory of the damselfish than outside the territory. Species richness was also higher inside the territory, mainly due to an increase in species richness of the free-living and sedentary types. These increases in abundance and species richness were caused by habitat structuring. TV setacea is a relatively tall and complicated alga with tangled rhizoids. Its dense stand inside the territory trapped a larger amount of sediment, which provided free-living foraminifera with heterogeneous and stable habitats. In addition, the dense stand of TV setacea provided sedentary-type foraminifera with a large, complex substratum, providing refuge and food inside the territory. This assumption was confirmed by the results of plate experiments showing that foraminiferal community structures were controlled by associations between foraminifera and algae. We showed that habitat-conditioning is an important process in biotic habitat-structuring and that habitat-conditioning by territorial damselfish maintains and enhances multi-species coexistence of foraminifera on coral rocks in a coral reef, (C) 2002 Elsevier Science B.V. All rights reserved.

書籍

講演・口頭発表等

  • 四国西部・瀬戸内海沿岸河川におけるニホンウナギの生息場所利用  [通常講演]
    三町 壮大, 山本 貫太, 植村 洋亮, 井上 幹生, 畑 啓生
    2019年度日本魚類学会年会 2019年09月 ポスター発表 高知
  • 産卵床であるイシガイ類の減少によるタナゴ類の在来種と国内外来種との交雑  [通常講演]
    植村 洋亮, 畑 啓生
    2019年度日本魚類学会年会 2019年09月 ポスター発表 高知
  • 沖縄県におけるなわばり性藻食スズメダイがサンゴと藻類群落との競争に与える影響  [通常講演]
    高野 翔太, 畑 啓生
    中国四国地区生物系三学会合同大会 2019年05月 ポスター発表
  • 魚類絶対寄生性を有するウオノエ科タイノエのミトコンドリアゲノム解析  [通常講演]
    大西 満希, 畑 啓生
    中国四国地区生物系三学会合同大会 2019年05月 ポスター発表
  • タンガニイカ湖における藻食魚類の機能形態にみられる多様化と局所適応  [通常講演]
    畑 啓生
    日本生態学会 第66回大会 2019年03月 ポスター発表
  • コイ目タナゴ亜科における希少在来種と人為移 入種との交雑と引き起こされた遺伝子浸透  [通常講演]
    植村 洋亮, 大内 魁人, 松葉 成生, 理, 畑 啓生
    日本生態学会 第66回大会 2019年03月 ポスター発表
  • 四国西部・瀬戸内海沿岸河川におけるニホンウ ナギの分布  [通常講演]
    山本 貫太, 三町 壮大, 植村 洋亮, 井上 幹生, 畑 啓生
    日本生態学会 第66回大会 2019年03月 ポスター発表
  • 魚類の口内に寄生する等脚類タイノエの配偶シ ステム  [通常講演]
    鈴木 絵美子, 武島 弘彦, 畑 啓生, 川西 亮太, 曽我部 篤
    日本生態学会第66回大会 2019年03月 ポスター発表
  • 自然共存域と人為移入由来地域におけるタナゴ亜科2種の交雑  [通常講演]
    植村洋亮, 畑啓生
    日本魚類学会 2018年10月 ポスター発表
  • 魚に寄生するウオノエを探してアマゾン川へ  [招待講演]
    畑 啓生
    平成30年度 大学連携市民講座 「大学から見た世界あれこれ」 2018年08月 公開講演,セミナー,チュートリアル,講習,講義等
  • 魚に寄生するウオノエ  [招待講演]
    畑 啓生
    西条自然学校夜の学校 2018年04月
  • マラウィ湖産ヒレ食シクリッドの捕食行動の左右性  [通常講演]
    竹内勇一, 畑啓生, 丸山敦, 山田拓人, 西川巧馬, Richard Zatha, Bosco Rusuwa
    2018年03月 ポスター発表
  • 魚食・鱗食・ヒレ食のシクリッド3種における口部形態の左右差の比較  [通常講演]
    西川巧馬, 丸山敦, 畑啓生, Richard Zatha, Bosco Rusuwa
    2018年03月 ポスター発表
  • 魚類絶対寄生者ウオノエ科等脚類の進化史  [通常講演]
    Hata, H, A. Sogabe, R. Kawanishi, H. Takeshima
    10th Indo Pacific Fish Conference 2017年10月 ポスター発表 Tahiti, French Polynesia
  • マラウィ湖に生息するヒレ食シクリッドの左右性  [通常講演]
    竹内勇一, 畑啓生, 丸山敦, 山田拓人, 西川巧馬, Richard Zatha, Bosco Rusuwa, 小田洋一
    日本動物学会 2017年09月 口頭発表(一般)
  • 魚をめぐる生きものたちのつながり  [通常講演]
    畑 啓生
    大学連携市民講座「大学から見た世界あれこれ」 2017年08月 坂の上の雲ミュージアム
  • 魚類絶対寄生性のウオノエ科等脚類の系統進化:寄生様式の多様化と淡水域への侵出  [通常講演]
    畑啓生, 曽我部篤, 川西亮太
    日本生態学会第64回全国大会 2017年03月 東京
  • 魚類絶対寄生者ウオノエ科等脚類の系統と寄生様式の多様化  [通常講演]
    曽我部篤, 川西亮太, 畑啓生
    日本生態学会 2016年03月 仙台
  • タンガニイカ湖のシクリッドにみられる生息場所の特殊化と多様化  [通常講演]
    H. Hata, M. Kohda, M. Hori
    Cichlid Science 2015年09月 Graz, Austria
  • 世界の古代湖〜魚たちの楽園〜  [招待講演]
    畑 啓生
    坂の上の雲ミュージアム・大学連携市民講座「世界を見よう、世界を知ろう」 2015年08月 坂の上の雲ミュージアム
  • 松山の絶滅危惧種ヤリタナゴを国内外来種アブラボテとの交雑から守れ!自然再生地を用いた希少種の保全  [招待講演]
    畑 啓生
    日本動物学会・中国四国植物学会・日本生態学会 中国四国地区生物系三学会合同大会公開シンポジウム「淡水魚をめぐる水辺の生物多様性−その機器と保全への取り組み−」 2015年05月 愛媛大学
  • 幻の魚をさがして  [通常講演]
    畑 啓生
    坂の上の雲ミュージアム市民講座「大学からアジアを見る」 2014年09月 坂の上の雲ミュージアム
  • 愛媛県における国内外来種アブラボテ−在来種ヤリタナゴをどう守る?−  [招待講演]
    松葉成生, 吉見翔太郎, 大内魁人, 井上幹生, 畑啓生
    第7回全国タナゴサミット 2014年01月 茨城県
  • 生態系における一次生産者と消費者とのネットワーク関係  [招待講演]
    Hata, H
    International Conference on Natural Science and Geological Aspect of Gorontalo 2012年09月
  • サンゴの森を拓き海藻を栽培する魚:なわばり性藻食魚と食藻との栽培共生  [招待講演]
    畑 啓生
    第4回愛媛大学学術フォーラム 2012年07月 愛媛大学
  • スズメダイの栽培共生にみられるインド-太平洋における地理的モザイク構造  [招待講演]
    Hata, H
    国立科学博物館国際シンポジウム2009, Origin of biodiversity by biological interactions 2009年11月 国立科学博物館
  • 魚類の左右性  [通常講演]
    Hata, H. M. Nakajima, Y. Takeuchi, M. Yasugi, H. Ashiwa, M. Nakae, K. Yamaoka, M. Kohda, J. Kitamura, M. Hori
    The 8th Indo-Pacific Fish Conference 2009年06月 Fremantle, Australia
  • 農業する魚:共生の海サンゴ礁で見られる新たな栽培共生  [招待講演]
    畑 啓生
    共生科学研究センターシンポジウム 2008年12月 奈良女子大学
  • タンガニイカ湖のシクリッドの藻園内にみられる特異なシアノバクテリア群集  [通常講演]
    Hata, H
    International symposium on systematics and diversity of fishes 2008年05月 Tokyo
  • サンゴ礁で藻類を栽培するスズメダイ  [招待講演]
    畑 啓生
    NGO法人OWS海のトークセッション第28回 2006年12月 丸の内さえずり館
  • スズメダイとの栽培共生が介在したイトグサ類の多様化  [招待講演]
    畑 啓生
    第38回種生物学シンポジウム 2006年12月 奥琵琶湖マキノセミナーハウス
  • スズメダイとイトグサとの絶対栽培共生  [通常講演]
    Hata, H, M. Kato, S. Ohkubo, H. Miyashita, M. Hori
    2006 Conference, Australian Coral Reef Society 2006年08月 Mission Beach, Australia
  • なわばり性スズメダイと藻類との相利関係  [通常講演]
    Hata, H
    7th Indo-Pacific Fish Conference 2005年05月 Taipei
  • サンゴ礁のなかの畑−スズメダイが営む藻園−  [招待講演]
    畑 啓生
    民族自然史研究会第38回例会 2005年01月 京大会館
  • サンゴ礁の中の藻園−なわばり性スズメダイ類に栽培されるイトグサ属藻類−  [招待講演]
    畑 啓生
    2004年度藻類談話会 2004年11月 奈良女子大学

MISC

受賞

  • 2019年12月 愛媛大学理学部 愛媛大学理学部研究奨励賞
     
    受賞者: 畑 啓生
  • 2018年09月 日本動物学会 Zoological Science論文賞
     Laterality is universal among fishes but increasingly cryptic among derived groups 
    受賞者: 堀;中島;畑;八杉;高橋;中江;山岡;幸田;北村;前畑;田中;岡田;竹内
  • 2018年04月 理学部ベストレクチャー賞
     
    受賞者: 畑 啓生
  • 2018年 日本動物学会 Zoological Science Award(論文賞)
     
    受賞者: 畑 啓生
  • 2013年 愛媛大学理学部 Teacher of the half year賞
     
    受賞者: 畑 啓生
  • 2013年 Zoological Science Award(論文賞)
     
    受賞者: 畑 啓生
  • 2011年 エスペック株式会社 エスペック環境研究奨励賞
     
    受賞者: 畑 啓生
  • 2006年 日本進化学会第8回大会優秀ポスター賞
     
    受賞者: 畑 啓生
  • 2005年 日本生態学会第52回大会ポスター賞優秀賞
     
    受賞者: 畑 啓生

共同研究・競争的資金等の研究課題

  • 地球温暖化下のサンゴ礁の復元力になわばり性藻食スズメダイが果たす役割
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 畑 啓生
  • 環境収容力推定手法開発事業・ウナギ課題
    水産庁委託事業:
    研究期間 : 2018年 -2023年
  • アフリカの二つの古代湖におけるシクリッド科魚類の摂食戦略の多様化と多種共存機構
    日本学術振興会:科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(B))
    研究期間 : 2018年10月 -2022年03月 
    代表者 : 丸山 敦, 畑 啓生, 竹内 勇一, ZIADI Fabienne, 八杉 公基
     
    2018年度の終盤に始まった本研究ではあるが、国内・国外での綿密な打ち合わせを経て、マラウイ湖への調査と試料採取、関連論文の執筆と公開、飼育実験計画の具体化など、全体として、十分な進捗を見せていると自己認識している。 具体的には、次の通りである。 マラウイ湖での研究では、現地調査を経て試料収集を組織的に進める目処が立ち、現地協力者による採集が継続されている。タンガニイカ湖での研究についても、現地調査は安全上の都合で2019年度に持ち越したものの、過去の研究で持ち帰った標本の譲渡を受けるなど、想定外の好条件が整いつつある。生体の輸入についても、可能性を示唆するいくつかの手がかりを得ている。 収集した試料は、従来的な形態分析に加えて順次マイクロCT分析にかけられた。統計的解析に向けて順調な準備が整いつつある。効率的に研究を進めるためのテレビ会議を経て、分析の優先順位についても共同研究者間で認識を共有した。すなわち、モデル魚種での新手法の方法論確立と公表を目下の最優先目標とし、ここで確立した手法を適用して効果的に種間比較を進め、進化的な考察へと結びつけていく方針である。 並行して、2つの湖それぞれでモデル魚種を1種ずつ選定し、その3DCG(3次元のグラフィックモデル)を作成する作業を開始した。これは、飼育環境下における行動観察実験において、捕食/逃避行動を誘発する際に革新的なメソドロジーを提供する可能性のあるものである。幸いにも、もっとも興味深い2種について生体の撮影に成功しており、前途は明るいと認識している。 また、本研究の申請の直接的な足がかりとなった複数の研究について、国際学術誌に掲載されるに至っている。
  • クルマエビ類に寄生するエビヤドリムシ科甲殻類の起源と特異性、及び宿主の免疫反応
    独立行政法人日本学術振興会:二国間交流事業 共同研究
    研究期間 : 2020年06月 -2022年03月
  • サンゴ群集の大規模白化からの再生になわばり性藻食スズメダイが果たす役割
    日本学術振興会:科学研究費助成事業 基盤研究(C)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 畑 啓生
     
    なわばりを持つ藻食性スズメダイ類は、サンゴ礁生態系において主要な一次消費者であり、そのなわばりは底質の11~70%を占めるほど高密度に存在するため、キーストーン種としての役割を持つ。2016年に海水温の上昇による世界的サンゴ大規模白化が発生し、国内最大のサンゴ礁である沖縄県石西礁湖においても約97%が白化、約56%が死滅した。この攪乱に対するサンゴ群集の復元力には、サンゴと競合する藻類を食べる藻食者が貢献するが、なわばりを持つ藻食性スズメダイ類の影響は謎である。本研究では、沖縄のサンゴ礁域で、白化前の2015年から観察しているスズメダイ6種のなわばり内外を追跡し、大規模白化からのサンゴ群集の初期再生の過程にスズメダイのなわばりが果たす役割を明らかにすることを目的としている。 2017年9月と2018年3月、9月、2019年3月に、沖縄本島周辺の瀬底島、恩納村、大度浜において6種のなわばり性スズメダイについて野外調査を行った。その結果、サンゴの大規模白化後に、サンゴの被度は、キオビスズメダイとクロソラスズメダイのなわばり内のみで有意に増加し、なわばり外では減少傾向にあることがわかった。また、なわばり内には、なわばり外に比べ高い頻度で出現する特徴的なサンゴ種が生育していること、大規模白化後に、これらのサンゴはなわばり外では消失したが、なわばり内では被度に変化が見られず維持されることが分かった。白化の影響を受けやすいとされるサンゴ種では、その被度は、大規模白化前ではなわばり外で高く、なわばり内ではほとんど見られなかったが、白化後はなわばり外で減少し、なわばり内で増加した。このことは、スズメダイのなわばり内が白化の影響を受けやすいサンゴ種の回復のための場所として機能している可能性を示唆した。
  • 植物食の起源とその多様な展開
    日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2015年04月 -2020年03月 
    代表者 : 加藤 真, 畑 啓生, 奥山 雄大, 川北 篤
     
    植物食がいつ、どのような分類群で起源し、そして植物利用様式をいかに刷新しつつ多様化していったのかを明らかにするために、以下の3つのテーマに沿って、自然史・生態調査と分子系統解析、および植物の形態や化学物質が介在した植物と植食者のふるまい(防衛・誘引・解毒)等の解析を行った。 (1)食植性昆虫における植物食の起源:コケに潜葉するハモグリバエ科とフショクバエ科の羽化標本を整理し、それらの形態観察を行った。その結果、コケ類に潜葉するハモグリバエ類とフショクバエ類は、いずれも寄主特異性が高く、非常に高い生物多様性を擁していることが明らかになった。 (2)食植性昆虫の植物利用様式の変遷と多様化過程:これまでに潜孔葉から羽化させた潜葉虫の成虫標本の整理を行い、潜葉虫の同定・分類を進めた。また、チャルメルソウ類を送粉するキノコバエ類が苔類食でかつ寄主特異性も高いことを明らかにし、学術誌に発表した。 (3)植物と食植性昆虫の間に成立した共生関係(特に送粉共生と栽培共生)の起源:コミカンソウ科の絶対送粉共生を新たに新大陸から見いだした。ペルーに分布するPhyllanthus属3種の送粉様式と、種子寄生性のハナホソガの分類および形態を調査し、その結果を学術誌に発表した。。 以上の研究に加えて、潮間帯の藻類食者の調査をした。ニシキウズ科ハナザラが、ウニの巣穴に住み込み、そこで付着藻類食を行っている一方、アコヤザラは波あたりの激しい岩上で不着想食を行っていることが明らかになった。ニシキウズ科チゴアシヤ亜科の近縁群の形態・生態情報とそれらの系統関係を調査し、貝殻の巻きがほどける進化過程について考察した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(A)
    研究期間 : 2016年04月 -2019年03月 
    代表者 : 榊原 正幸, 世良 耕一郎, 畑 啓生, 大森 浩二, 佐野 栄, N.P Bhandary, 田中 勝也, 古川 慎哉, 笠松 浩樹, 小松 悟, 武部 博倫, 島上 宗子
     
    東南アジア地域では,貧困問題を背景とする零細小規模金採掘による水銀汚染が発生し、近年、住民の健康リスクが顕在化している。本研究では、インドネシアのゴロンタロ州における水銀汚染の環境影響評価および住民の健康影響評価を実施した。そして,それらの調査結果を住民および行政に周知すると同時に,研究者の「科学知」と住民の「経験知」を統合することによって,伝統的産業を活性化について住民と協議した。また、これらの研究を通して,持続的に貧困問題を改善しつつ,水銀汚染リスクを低減する未来シナリオを協力した住民と共創し、持続可能な地域社会づくりの方法論を確立した。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 小田 洋一, 畑 啓生, 竹内 勇一
     
    アフリカのタンガニーカ湖とマラウィ湖にそれぞれ生息する鱗食魚(Perissodus microlepis,P.m.とGenyochromis mento, G.m.)の捕食行動における左右性の獲得過程を理解することを目的とした.これらを採集し,胃内容に含まれる鱗から左右性行動を推定し,下顎形態の左右性との対応を明らかにした.P.m.は人工繁殖に世界で初めて成功し,捕食行動のキネティクスには生得的な左右差があること,捕食経験によりその左右差が発達することを示した.一方、G.m.は鱗/鰭食であることを明らかにし,また初めて水槽内での捕食行動観察に成功し,P.m.に比べて弱い左右性を見出した.
  • 愛媛県内のコイヘルペスウイルス病発生のメカニズム解明と予防法の開発
    公益信託 伊予銀行環境基金「エバーグリーン」:
    研究期間 : 2016年09月 -2017年08月 
    代表者 : 畑 啓生
  • 日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2013年04月 -2016年03月 
    代表者 : 畑 啓生, 堀 道雄, 幸田 正典, 越智 晴基, 多田 真也, 増原 碩之
     
    魚類における藻食への適応とその多様化、それが多種共存に果たす役割を明らかにすることを目的とした。各地でなわばり性藻食スズメダイ計5種について調査した結果、スズメダイの藻園管理は種ごとに集約的から粗放的まで勾配があり、狭い藻園ほど侵入者の追い払いを徹底的に行い、藻園が広くなるほど侵入者の追い払いにコストをかけないことがわかった。タンガニイカ湖の藻食シクリッド科魚類では、適応放散の過程で、まず摂食様式を多様化させ、さらに生息場所を特殊化させて異なる餌ニッチへの分化を成し遂げ、多種共存が可能となっていることが分かった。
  • 日本学術振興会:科学研究費助成事業 基盤研究(B)
    研究期間 : 2010年 -2012年 
    代表者 : 幸田 正典, 宗原 弘幸, 松本 一範, 畑 啓生
     
    脊椎動物の社会進化モデルとしてタンガニイカ湖のカワスズメの系統関係や彼らの社会構造を調べた。この系統の魚類には多様な婚姻形態や社会構造が含まれており、共同繁殖の進化には巣の維持という生態条件が重要であることが示された。また「共同的一夫多妻」などほ乳類や鳥類でもまったく知られていない社会構造も見いだした。新たな系統からの血縁ヘルパー型共同繁殖魚や協同的一妻多夫の進化も示唆できるなど、様々な成果が得られた。
  • 日本学術振興会:科学研究費助成事業 若手研究(B)
    研究期間 : 2010年 -2012年 
    代表者 : 畑 啓生
     
    水域生態系の一次生産者藻類と、それを利用する藻食魚とのネットワーク関係をアフリカの古代湖、タンガニイカ湖で調査した。ザンビア国カセンガ岩礁域では、14種に及ぶ藻食性シクリッド類が共存している。それらシクリッド類の藻園となわばり外から藻類を採集し、またシクリッド類の胃内容物を採集し、16SrDNA領域を用いてメタゲノミクス解析を行い、藻類の組成を明らかにした。結果、シアノバクテリア類と珪藻類が主な餌として利用されていることが分かり、またDNAの塩基配列レベルで微小な藻類を種レベルで分類することで、同じギルドに属する種間でも、防衛する資源や、その利用が異なることが分かった。
  • 日本学術振興会:科学研究費助成事業 若手研究(スタートアップ)
    研究期間 : 2008年 -2009年 
    代表者 : 畑 啓生
     
    サンゴ礁に生息する藻食性スズメダイは、なわばり内に藻類の畑を維持する。琉球列島では、クロソラスズメダイは不要な藻類を除藻することで、餌に適した一種類のイトグサ種を繁茂させている。このスズメダイはインド-太平洋に広く分布するため、その地理的変異を調べたところ、この広い分布域で、スズメダイとイトグサとの間に高い特異性が保たれていた。同時に、海域によってはスズメダイが利用するイトグサ種が異なることもあった。これにより、水域でも、陸上に見られるように、一次生産者(藻類)と、その消費者(藻食魚)との間に高い種特異性があることが分かった。この特異性は、水域においても生物多様性の形成や維持に重要な役割を果たしていると考えられる。
  • なわばり性藻食魚とその食藻との相利共生:魚類による栽培の起源と進化
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2005年 -2007年 
    代表者 : 畑 啓生
     
    水圏生態系において、藻食性なわばり魚と藻類との間に見つかった栽培共生系について、その起源と進化を明らかにするため研究を行った。 琉球列島のサンゴ礁域ではスズメダイ類と、そのなわばりに繁茂する糸状紅藻イトグサ類との間に高い種特異性があり、中でもクロソラスズメダイとイトグサsp.1とは、互いに互いの生存を依存しあう絶対栽培共生に達していた。この発見はNHKの番組ダーウィンが来た!生きもの新伝説において「大発見!農業する魚」として取り上げられ一般の関心を引いた。 クロソラスズメダイとイトグサとの関係性のインドー太平洋における地理的変異を明らかにするため、各地のサンゴ礁を訪れ、藻類を採集し分析を行った。その結果、モーリシャスとオーストラリアでも、クロソラスズメダイのなわばりから全く同じイトグサsp.1が見つかり、一方イトグサsp.1はクロソラスズメダイのなわばり外には全く生息していなかった。またエジプトやケニヤ、モルディブでは、クロソラスズメダイはイトグサsp,1と極めて近縁なイトグサ類とそれぞれ栽培共生を結んでいた。こうして、クロソラスズメダイとイトグサとの栽培共生は、インド-西太平洋の広い海域で保たれ、かつ海域によってはイトグサ近縁種への寄主転換があることが分かった。 同時に、アフリカタンガニイカ湖のなわばり性シクリッドについて、その藻類利用を調査した。これらのシクリッドのなわばり内にはシアノバクテリアの一群が繁茂しており、シクリッドの胃内容からもそれらが見つかる。分子生物学的手法を用い、それらのシアノバクテリアの正体が突き止められ、シクリッド類が種ごとにそれぞれのシアノバクテリア種を利用しているのかどうかが明らかにされようとしている。 これらの研究により、水域における藻食魚と藻類との相互作用系について、藻類の知られざる多様性や藻食者との高い種特異性が明らかにされつつある。
  • 藻食魚クロソラスズメダイとそのなわばり内に純群落を形成する藻類との相利共生
    日本学術振興会:科学研究費助成事業 特別研究員奨励費
    研究期間 : 2003年 -2004年 
    代表者 : 畑 啓生
     
    サンゴ礁は最も生物多様性が高い生態系の一つとして知られており、多様な藻食性生物のかじり食によって、海藻群落の発達は著しく制限されている。しかし、サンゴ礁の中には多くの種のスズメダイ類がかじり食者からなわばりを防衛し、その中に糸状藻類の繁茂した藻類群落、すなわち藻園を維持している。 多くの藻園は様々な藻類が入り混じったものであるのに対し、私は今までの研究で、琉球列島のクロソラスズメダイの藻園は例外的に一種の藻類ハタケイトグサのみによって優占されており、クロソラスズメダイは藻食者からの防衛に加えて除藻を行っていることを発見した。 そこで、藻園の単作と混作の生態学的意義を明らかにするため、同所的に生息する同属のホシゾラスズメダイ(Stegastes obreptus)と、クロソラスズメダイとで、藻園の構造とその管理行動を比較した。その結果、ホシゾラスズメダイは除藻を伴なわない粗放的な管理によって広い混作藻園を維持しているのと対照的に、クロソラスズメダイは集約的な藻園管理によって、狭いながらも面積当たりの現存量が高い単作藻園を維持していることが明らかになった。 琉球列島における集中的な採集と分子実験によって、ハタケイトグサは藻園の外には全く見られず、クロソラスズメダイにその生存を強く依存していることがわかった。こうして、クロソラスズメダイとハタケイトグサとは、生息場所と餌資源とをそれぞれ提供して、その生存を支えあう栽培共生の関係にあることがわかった。

委員歴

  • 2018年04月 - 現在   日本生態学会中国四国支部   愛媛県幹事

社会貢献活動

  • 愛媛県野生動植物保護推進委員
    期間 : 2020年04月01日 - 現在
    役割 : 調査担当
    主催者・発行元 : 愛媛県
  • 魚をめぐる生きものたちのつながり
    期間 : 2017年09月
    役割 : 講師
    主催者・発行元 : 坂の上の雲ミュージアム
    イベント・番組・新聞雑誌名 : 市民講座

メディア報道

  • 「農耕」する生き物たち
    報道 : 2020年03月11日
    発行元・放送局 : 神戸新聞
    番組・新聞雑誌 : 神戸新聞
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年03月09日
    発行元・放送局 : 静岡新聞
    番組・新聞雑誌 : 静岡新聞
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年03月09日
    発行元・放送局 : 信濃毎日新聞
    番組・新聞雑誌 : 信濃毎日新聞
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年03月07日
    発行元・放送局 : 河北新報
    番組・新聞雑誌 : 河北新報
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年03月06日
    執筆者 : 本人以外
    発行元・放送局 : 四国新聞
    番組・新聞雑誌 : 四国新聞
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年03月01日
    執筆者 : 本人以外
    発行元・放送局 : 中国新聞
    番組・新聞雑誌 : 中国新聞
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年02月28日
    発行元・放送局 : 熊本日日新聞
    番組・新聞雑誌 : 熊本日日新聞
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年02月26日
    発行元・放送局 : 北海道新聞
    番組・新聞雑誌 : 北海道新聞
     新聞・雑誌
  • 「農耕」する生き物たち
    報道 : 2020年02月26日
    発行元・放送局 : 山形新聞
    番組・新聞雑誌 : 山形新聞
     新聞・雑誌

学術貢献活動

  • 日本生態学会愛媛県幹事
    期間 : 2018年04月01日 - 現在
    種別 : 学会・研究会等

愛媛大学教員活動実績

教育活動(B)

担当授業科目(B01)

  • 2019, 前期, 学部, 生物学Ⅰ
  • 2019, 前期, 学部, 生物学序論
  • 2019, 前期, 学部, 基礎生物英語
  • 2019, 前期, 学部, 臨海実習
  • 2019, 前期, 学部, 生物学ゼミナールⅠ
  • 2019, 前期, 学部, 生物学特別演習Ⅰ
  • 2019, 前期, 学部, 行動生態学
  • 2019, 前期, 学部, 卒業研究Ⅰ
  • 2019, 前期, 修士, 生物環境科学高等実習Ⅱ
  • 2019, 前期, 修士, 生物学ゼミナールI
  • 2019, 前期, 修士, 生物学課題実験I
  • 2019, 前期, 学部, 生物学
  • 2019, 前期, 学部, 臨海実習
  • 2019, 前期, 学部, 行動生態学


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