2024/02/02 更新

写真a

フジオカ ハルナ
藤岡 春菜
FUJIOKA HARUNA
所属
環境生命自然科学学域 助教
職名
助教
ホームページ
外部リンク

学位

  • 学術 ( 2020年3月   東京大学 )

研究キーワード

  • 動物行動学

  • 時間生物学

  • 社会性昆虫

  • アリ

  • 概日リズム

  • 日周リズム

  • 栄養交換

経歴

  • 岡山大学   大学院環境生命科学研究科   助教

    2021年10月

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    国名:日本国

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  • 大阪市立大学   日本学術振興会 特別研究員CPD

    2020年10月 - 2021年9月

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  • 大阪市立大学   日本学術振興会 特別研究員PD

    2020年3月 - 2020年10月

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  • 東京大学   大学院総合文化研究科   日本学術振興会 特別研究員(DC2)

    2018年4月 - 2020年3月

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論文

  • Diacamma ants adjust liquid foraging strategies in response to biophysical constraints

    Haruna Fujioka, Manon Marchand, Adria C. LeBoeuf

    Proceedings of the Royal Society B: Biological Sciences   290 ( 2000 )   2023年6月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Royal Society  

    Ant foragers provide food to the rest of the colony, often requiring transport over long distances. Foraging for liquid is challenging because it is difficult to transport and share. Many social insects store liquids inside the crop to transport them to the nest, and then regurgitate to distribute to nest-mates through a behaviour called trophallaxis. Some ants instead transport fluids with a riskier behaviour called pseudotrophallaxis—holding a drop of liquid between the mandibles through surface tension. Ants share this droplet with nest-mates without ingestion or regurgitation. We hypothesised that ants optimize their liquid-collection approach depending on viscosity. Using an ant that employs both trophallaxis and pseudotrophallaxis, we investigated the conditions where each liquid-collection behaviour is favoured by measuring biophysical properties, collection time and reaction to food quality for typical and viscosity-altered sucrose solutions. We found that ants collected more liquid per unit time by mandibular grabbing than by drinking. At high viscosities ants switched liquid collection method to mandibular grabbing in response to viscosity and not to sweetness. Our results demonstrate that ants change transport and sharing methods according to viscosity–a natural proxy for sugar concentration–thus increasing the mass of sugar returned to the nest per trip.

    DOI: 10.1098/rspb.2023.0549

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    その他リンク: https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2023.0549

  • Socially transferred materials: why and how to study them 査読

    Sanja Maria Hakala, Haruna Fujioka, Katharina Gapp, Ornela De Gasperin, Eléonore Genzoni, Rebecca M. Kilner, Joris M. Koene, Barbara König, Timothy A. Linksvayer, Marie-Pierre Meurville, Matteo A. Negroni, Hugo Palejowski, Stuart Wigby, Adria C. LeBoeuf

    Trends in Ecology & Evolution   2022年12月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier BV  

    DOI: 10.1016/j.tree.2022.11.010

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  • Individual Ants Do Not Show Activity-Rest Rhythms in Nest Conditions

    Haruna Fujioka, Masato S. Abe, Yasukazu Okada

    Journal of Biological Rhythms   36 ( 3 )   297 - 310   2021年6月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:SAGE Publications  

    Circadian rhythms, which respond to the day-night cycle on the earth, arise from the endogenous timekeeping system within organisms, called the “biological clock.” For accurate circadian rhythms, daily fluctuations in light and temperature are considered one of the important time cues. In social insects, both abiotic and biotic factors (i.e., social interactions) play a significant role in activity-rest rhythm regulation. However, it is challenging to monitor individual activity-rest rhythms in a colony because of the large group size and small body size. Therefore, it is unclear whether individuals in a colony exhibit activity-rest rhythms and how social interactions regulate their activity-rest rhythms in the colony. This study developed an image-based tracking system using 2D barcodes for Diacamma cf. indicum from Japan (a monomorphic ant) and measured the locomotor activities of all colony members under laboratory colony conditions. We also investigated the effect of broods on activity-rest rhythms by removing all broods under colony conditions. Activity-rest rhythms appeared only in isolated ants, not under colony conditions. In addition, workers showed arrhythmic activities after brood removal. These results suggested that a mixture of social interactions, and not light and temperature, induces the loss of activity-rest rhythms. These results contribute to the knowledge of a diverse pattern of circadian activity rhythms in social insects.

    DOI: 10.1177/07487304211002934

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    その他リンク: http://journals.sagepub.com/doi/full-xml/10.1177/07487304211002934

  • Bipartite network analysis of ant-task associations reveals task groups and absence of colonial daily activity

    Haruna Fujioka, Yasukazu Okada, Masato S. Abe

    Royal Society Open Science   8 ( 1 )   201637 - 201637   2021年1月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Royal Society  

    Social insects are one of the best examples of complex self-organized systems exhibiting task allocation. How task allocation is achieved is the most fascinating question in behavioural ecology and complex systems science. However, it is difficult to comprehensively characterize task allocation patterns due to behavioural complexity, such as the individual variation, context dependency and chronological variation. Thus, it is imperative to quantify individual behaviours and integrate them into colony levels. Here, we applied bipartite network analyses to characterize individual-behaviour relationships. We recorded the behaviours of all individuals with verified age in ant colonies and analysed the individual-behaviour relationship at the individual, module and network levels. Bipartite network analysis successfully detected the module structures, illustrating that certain individuals performed a subset of behaviours (i.e. task groups). We confirmed age polyethism by comparing age between modules. Additionally, to test the daily rhythm of the executed tasks, the data were partitioned between daytime and nighttime, and a bipartite network was re-constructed. This analysis supported that there was no daily rhythm in the tasks performed. These findings suggested that bipartite network analyses could untangle complex task allocation patterns and provide insights into understanding the division of labour.

    DOI: 10.1098/rsos.201637

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    その他リンク: https://royalsocietypublishing.org/doi/full-xml/10.1098/rsos.201637

  • A specific type of insulin-like peptide regulates the conditional growth of a beetle weapon

    Yasukazu Okada, Masako Katsuki, Naoki Okamoto, Haruna Fujioka, Kensuke Okada

    PLOS Biology   17 ( 11 )   e3000541 - e3000541   2019年11月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Public Library of Science (PLoS)  

    Evolutionarily conserved insulin/insulin-like growth factor (IGF) signaling (IIS) has been identified as a major physiological mechanism underlying the nutrient-dependent regulation of sexually selected weapon growth in animals. However, the molecular mechanisms that couple nutritional state with weapon growth remain largely unknown. Here, we show that one specific subtype of insulin-like peptide (ILP) responds to nutrient status and thereby regulates weapon size in the broad-horned flour beetle Gnatocerus cornutus. By using transcriptome information, we identified five G. cornutus ILP (GcorILP1-5) and two G. cornutus insulin-like receptor (GcorInR1, -2) genes in the G. cornutus genome. RNA interference (RNAi)-mediated gene silencing revealed that a certain subtype of ILP, GcorILP2, specifically regulated weapon size. Importantly, GcorILP2 was highly and specifically expressed in the fat body in a condition-dependent manner. We further found that GcorInR1 and Gcor-InR2 are functionally redundant but that the latter is partially specialized for regulating weapon growth. These results strongly suggest that GcorILP2 is an important component of the developmental mechanism that couples nutritional state to weapon growth in G. cornutus. We propose that the duplication and subsequent diversification of IIS genes played a pivotal role in the evolution of the complex growth regulation of secondary sexual traits.

    DOI: 10.1371/journal.pbio.3000541

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  • Liquid exchange via stomodeal trophallaxis in the ponerine ant Diacamma sp. from Japan

    Haruna Fujioka, Yasukazu Okada

    Journal of Ethology   37 ( 3 )   371 - 375   2019年9月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media LLC  

    Trophallaxis plays a major role in the sharing of food in colonies of many social insects, and two modes of this are known: stomodeal (oral) and proctodeal (abdominal) trophallaxis. In social Hymenoptera, only a small proportion of colony members perform the task of food collection, and oral trophallaxis is predominant in their social sharing of food. Typically, foragers distribute liquid food stored in their crop to nestmates via oral trophallaxis. Similar to bees, some ants (Formicidae) forage for liquid food from plant secretions (nectars) and insect exudates (honeydew). While regurgitation is common in ants, it has been documented in only two species of the Ponerinae. Here, we report the ability of Diacamma sp. from Japan to perform trophallaxis. After thirsty ants had been paired with ants provided with colored water, the abdomens of both groups of ants were dissected. The digestive organ was colored red in half of the receivers. In addition, we observed mouth-to-mouth interactions in the laboratory, not “social bucket” behavior (i.e., exchange of liquid held between mandibles). Our results suggest that Diacamma sp. can exchange liquid by true oral trophallaxis and shed new light on social organization via liquid exchange.

    DOI: 10.1007/s10164-019-00602-9

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    その他リンク: http://link.springer.com/article/10.1007/s10164-019-00602-9/fulltext.html

  • Observation of plugging behaviour reveals entrance‐guarding schedule of morphologically specialized caste in Colobopsis nipponicus

    Haruna Fujioka, Masato S. Abe, Yasukazu Okada

    Ethology   125 ( 8 )   526 - 534   2019年8月

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    担当区分:筆頭著者, 責任著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley  

    The success of social insects is often attributed to the specialized morphologies and behaviours of workers. One of the most elaborate specializations in ant species is the workers’ plugging behaviour, in which their uniquely shaped heads are used for nest defence. These species generally nest in tree cavities. Without morphologically specialized workers (major workers) plugging the nest entrance, nests are easily attacked and replaced by conspecific and heterospecific cavity-dwelling ants and other predators. Therefore, major workers are expected to defend the nest at all times. However, empirical evidence on the social time investment for nest defence is still lacking. Here, we investigated how major workers of Colobopsis nipponicus achieve nest defence (plugging behaviour) in terms of their work schedule. Our results showed that the nests had more major workers than entrances. The observation of artificial plastic nests over 6 days in the laboratory revealed that the nest entrance was guarded almost continuously by multiple major workers. The entrance-guarding schedule was not equally divided among major workers, and there were no clear shift patterns in the timing of changeovers. We highlight the importance of investigating the time investment of workers to fully understand the defence strategies of this morphologically specialized caste.

    DOI: 10.1111/eth.12877

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    その他リンク: https://onlinelibrary.wiley.com/doi/full-xml/10.1111/eth.12877

  • Ant activity-rest rhythms vary with age and interaction frequencies of workers

    Haruna Fujioka, Masato S. Abe, Yasukazu Okada

    Behavioral Ecology and Sociobiology   73 ( 3 )   2019年3月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media LLC  

    Abstract: Social insect colonies are highly organized systems, where communication among nestmates (i.e., social interactions) has a pivotal function for colonial organization. In order to further the understanding of social organization, the chronobiological system of social insect species, particularly their circadian rhythm, has recently attracted much attention. However, gaps still remain in our understanding of how individual active/rest rhythms are governed in various social contexts. In this study, we investigate the effects of worker-worker interactions on circadian activity rhythms, using the monomorphic ant, Diacamma sp. Continuous tracking of solitary ants elucidated circadian activity rhythms, both in young and old workers (< 30 days and > 70 days after eclosion, respectively). The color tag–based automatic tracking of multiple workers revealed that young-old interactions reduced circadian rhythmic activities in both young and old workers, whereas young workers retained active/rest rhythms under young-young worker interactions. Together with the analyses of worker-worker interaction frequencies, we conclude that interactions between workers in different age groups (i.e., workers with different tasks) function as different cues to alter worker active/rest patterns. We discuss the potential roles of worker-worker interactions on the chronobiological organization of the ant society. Significance statement: In social animals, how individual behavioral rhythms are governed by social interactions is a fundamental question towards the mechanistic understanding of complex biological systems. Using an image-based tracking system, we composed artificial ant worker groups consisting of different functions (i.e., young nurses and old foragers) and investigated whether the age composition and the resulting interactions had an effect on the active/rest rhythms of individual workers, and of the whole group. In solitary conditions, both young and old workers showed circadian activity; however, when grouped with workers from different age groups, both young and old workers turned to show weak circadian rhythmicity or around-the-clock activity. Our results suggest that even simple social cues (i.e., frequency of contact with young and old workers) could alter worker activity patterns. To our knowledge, this is the first evidence showing that specific worker-worker interaction induces weakly rhythmic and/or arrhythmic states.

    DOI: 10.1007/s00265-019-2641-8

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    その他リンク: http://link.springer.com/article/10.1007/s00265-019-2641-8/fulltext.html

  • Ant circadian activity associated with brood care type

    Haruna Fujioka, Masato S. Abe, Taro Fuchikawa, Kazuki Tsuji, Masakazu Shimada, Yasukazu Okada

    Biology Letters   13 ( 2 )   20160743 - 20160743   2017年2月

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    担当区分:筆頭著者   掲載種別:研究論文(学術雑誌)   出版者・発行元:The Royal Society  

    In group-living animals, social interactions influence various traits including circadian activity. Maternal care, in particular, can have a strong effect on the circadian activity of parents or nurses across taxa. In social insects, nest-mates are known to have diverse activity rhythms; however, what kind of social environment is crucial in shaping an individual's rhythm is largely unknown. Here, we show that the focal brood types being taken care of (i.e. egg, larva and pupa) have significant effects on individual activity/rest rhythm, using the monomorphic ant
    <italic>Diacamma</italic>
    (putative species
    <italic>indicum</italic>
    ). When isolated from a colony, nurses exhibited a clear circadian rhythm. However, when paired with eggs or larvae, they exhibited around-the-clock activity with no apparent rhythm. In contrast, a clear activity rhythm emerged when nurses were paired with a pupa, requiring little care. Such brood-type-specific changes in circadian activity are considered to arise from the difference in caretaking demands. Our finding may contribute to the understanding of the organization of a colony in the context of behavioural variability under different microenvironments.

    DOI: 10.1098/rsbl.2016.0743

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    その他リンク: https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2016.0743

  • 動物社会における行動の定量的計測とデータ解析 査読

    阿部真人, 藤岡春菜

    日本ロボット学会誌   36 ( 6 )   22 - 28   2017年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.7210/jrsj.35.455

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▼全件表示

共同研究・競争的資金等の研究

  • スズメバチにおける栄養交換の機能解析

    2022年

    八雲財団 

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    担当区分:研究代表者 

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  • アリ類における生物時計の社会的制御機構と適応的意義の解明

    研究課題/領域番号:20J01766  2020年04月 - 2022年03月

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    藤岡 春菜

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    担当区分:研究代表者 

    配分額:4810000円 ( 直接経費:3700000円 、 間接経費:1110000円 )

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  • 時空間からみた社会性昆虫の分業メカニズム:全個体トラッキングによるアリの行動解析

    研究課題/領域番号:18J13369  2018年04月 - 2020年03月

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    藤岡 春菜

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    配分額:1700000円 ( 直接経費:1700000円 )

    社会性昆虫では、ワーカー(働きアリ)が巣内の育児や掃除、防御、採餌などさまざま仕事について、分業が行われている。どの個体がどの仕事を行うかという担当は、日齢によっておおまかに決まるが、コロニー(巣)内の状況により、仕事量は変動する。その変動に柔軟に対応するため、個体間相互作用による仕事の割り当てや働く時間の調整がなされていると考えられる。しかし、技術的な問題から、社会性昆虫の集団レベルでの定量的な行動観察はほとんど行われていなかった。本研究は、コロニーレベルでトゲオオハリアリ(Diacamma sp. from Okinawa)の行動を定量的に測定し、各個体の仕事内容がどのように決まるのかという、分業メカニズムの解明をめざした。
    本年度は、継時的な飼育により各個体の日齢を把握している、計11コロニーを観察し、どの個体が、いつ何をしているのかを解析した。位置情報から自動的に巣内と巣外の滞在時間を個体ごとに計算し、外勤活動率を調べた。従来の報告通り、老齢の個体が外勤活動を盛んに行なっていたものの、同じ齢でも個体差が大きいことを発見した。このことから、採餌個体は、日齢だけではなく、生理状態や経験など、複数の要因によって、影響を受けることが示唆された。さらに、1日の中で、採餌など外勤活動や育児活動には、変動がなく、昼夜問わず仕事をしていることがわかった。この成果について、論文化に向け準備中である。

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