Center for Ecological Research, Kyoto University

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CER seminars

CER holds a seminar inviting outside people at the lecture room 2 on the third Friday of each month (which may change) except in August and March. In addition, we special hold CER seminars and independent open seminars irregularly. For the CER seminar schedule, please see the CER website.

To prevent the spread of covid-19, CER seminars are currently only available in either 1) within-CER limited zoom distribution or 2) online web (live) distribution , depending on the situation. Please note that the seminar will not be available at the Center for Ecological Research, which is different from regular seminars (17 July, 2020).

318th 18 September, 2020 (Fri.) 14:00~17:00

Takeshi Osawa (Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University)

(within-CER limited zoom distribution)

Strategic management for alien invasive plants -case for Ogasawara islands-

Ogasawara islands is one of highest biodiversity area in Japan. In Ogasawara islands there are investing much efforts for management of the alien invasive species. In any cases on management of alien invasive species, effective and low-cost management strategies are needed. In this talk I would like to introduce the basic idea on what is management strategy first, then, I reviewed current status for management on 3 alien invasive plants these are Bischofia javanica, Leucaena leucocephala and Casuarina equisetifolia in Ogasawara islands. Finally I would like to introduce some studies which aim to contribute management strategy on Leucaena leucocephala in Ogasawara islands.

Kenji Hata (College of Commerce, Nihon University)

(within-CER limited zoom distribution)

Loss of ecosystem functions caused by severe disturbances of feral goats in oceanic islands can limit restoration

For restoration and management of ecosystems disturbed by invasive mammals, they have been eradicated in many islands. Ecosystem recovery after the eradication would depend on processes of loss of ecosystem functions before and after their eradication. I introduce several studies about processes of changes in ecosystem functions before and after eradication of feral goats in Nakodo-jima, a subtropical archipelago in the northwestern Pacific. I focused on relationships between vegetation states and soil chemical properties with vegetation degradation, soil erosion. In addition, I propose a new framework of more flexible and practical restoration of island ecosystem disturbed by invasive mammals using a concept "novel ecosystem", which should be one of goals of disturbed ecosystems in islands.

317th 17 July, 2020 (Fri.) 14:00~17:00

Kohmei Kadowaki (Field Science Education and Research Center, Kyoto University)

(online web distribution)

Plant-soil feedback and the dynamics of temperate forest communities

Plant-soil feedback is defined as an interaction among plants, soil organisms, and abiotic soil conditions, and recent studies suggest that plant-soil feedback is considered as a significant factor regulating plant species diversity and community structure. I have investigated how soil fungi mediate plant-soil feedback and affect the structure and dynamics of tree communities through field manipulation experiments. In the seminar I show some recent findings about the effects of plant soil feedback revealed by comprehensive analysis of various seedling growth parameters, soil chemical composition, soil microbial communities and above-ground herbivorous insects and predator communities. I focus primarily on the effects of plant-soil feedback on seedling growth inequality and the role of terrestrial herbivorous and predatory insects, both of which have often been neglected in previous studies.

Yasuo YAMAUCHI (Graduate School of Agricultural Science, Kobe University)

(within-CER limited zoom distribution)

How plants use volatiles as communication tools?

Green leaf volatiles (GLVs) are rapidly emitted volatiles when leaves are wounded. (E)-2-Hexenal is a representative member of GLVs emitted when not only wounded but oxidative and heat stress conditions. (E)-2-Hexenal induces oxidative and heat stress-responsive genes, thus (E)-2-Hexenal acts as an infochemical involved in the stresses. Rapid production of (E)-2-Hexenal is supported by a series of enzymes, and plants can recognize 2-hal by plausible receptor resemble those of mammals and insects. Therefore, plants can communicate with others via (E)-2-Hexenal to inform the coming emergency. In this seminar, I introduce a concept that plants use volatile infochemicals as "Phyto-language" as communication tools.

316th 19 June, 2020 (Fri.) 14:00~17:00

Michitaka Notaguchi (Nagoya University)

(within-CER limited zoom distribution)

Study on Nicotiana grafting revealed a common mechanism among grafting, wound healing and parasitism

Ken Naito (NARO)

(within-CER limited zoom distribution)

I am mesmerized -Diversity and utility of salt tolerance evolution in the genus Vigna

315th 15 May, 2020 (Fri.) 14:00~17:00

Shin-ichi Nakano (Center for Ecological Research, Kyoto University)

(within-CER limited zoom distribution)

A unique microbial loop in the hypolimnion of Lake Biwa

Noboru Okuda (Center for Ecological Research, Kyoto University)

(within-CER limited zoom distribution)

Ecology in Transdisciplinary Science: A case study of watershed governance

315th 17 April, 2020 (Fri.) 14:00~17:00 Canceled

This Seminar has been canceled due to the severe situation where coronavirus (COVID-19) is still expanding. The abstract of the scheduled lecture will be posted as it is.

Matteo Convertino (Faculty of Information Science and Technology, Hokkaido University)

Critical Interactions: Disentangling Environment-Biota Complexity across Life Scales in Basin Ecosystems

A unified theoretical and computational multiplex metacommunity model is presented to infer, predict and design complex ecosystems at different biological and spatio-temporal scales. The fundamental role of the environment (specifically hydrogemorphological networks) and critical interactions is highlighted in shaping functional species networks, extreme events, and phase transitions associated to healthy and dysbiotic ecosystems states. The model is proposed for ecosystems of increasing complexity form rivers, wetlands, to ocean systems in which species populations and communities are analyzed. Patterns of collective organization and early-warning indicators are proposed to assess the optimality of ecosystems and their divergence. The quest is for a general metabolic theory of basin ecosystem function (such as information processing machines) which leads to understanding complex environmental dynamics underpinning biota organization, bio-inspired monitoring technology design, and multiscale ecosystem engineering for desired ecosystem services. Examples of ongoing microbiome engineering projects connecting science and technology are provided for aquatic and terrestrial ecosystems as well as ecohydrological design where ecological function is explicitly taken into account.

Kohmei Kadowaki (Field Science Education and Research Center, Kyoto University)

Plant-soil feedback and the dynamics of temperate forest communities

Plant-soil feedback is defined as an interaction among plants, soil organisms, and abiotic soil conditions, and recent studies suggest that plant-soil feedback is considered as a significant factor regulating plant species diversity and community structure. I have investigated how soil fungi mediate plant-soil feedback and affect the structure and dynamics of tree communities through field manipulation experiments. In the seminar I show some recent findings about the effects of plant soil feedback revealed by comprehensive analysis of various seedling growth parameters, soil chemical composition, soil microbial communities and above-ground herbivorous insects and predator communities. I focus primarily on the effects of plant-soil feedback on seedling growth inequality and the role of terrestrial herbivorous and predatory insects, both of which have often been neglected in previous studies.

Special 28 February, 2020 (Fri.) 14:00~15:30

Ji Zhou (Head of Data Sciences, Cambridge Crop Science, UK; Professor of Crop Phenomics, Nanjing Agricultural University, China)

Multi-scale crop phenomics for breeding resource use efficiency cereal crops between the UK and China

With the development of cross-disciplinary research, plant phenotyping and phenotypic analysis have become a popular research domain in recent years, an area catalysed by a range of technologies such as computer vision, remote sensing, machine learning and deep learning. Phenotyping is aiming to collect evidence of plant during its entire life cycle and at different scales. Using indoor and outdoor phenotyping platforms in the UK and China, we are studying a variety of key performance-related phenotypes for both wheat and rice. We analysed different levels of phenotypes for cereal crops, from cells, tissues, organs and plants, to plots and fields, in a high-throughput and reproducible manner. Phenotypic analysis results are then utilised for gene discovery, crop breeding, cultivation, and agricultural production. In the seminar, the speaker is going to talk about these platforms and how they are applied in studying resource use efficiency for wheat and genetic variation for rice. A number of new deep learning and computer vision approaches will also be introduced, which unravel how to extract complex traits that enabled us to link traits to key genes in multi-year field experiments.

314th 21 February, 2020 (Fri.) 14:00~17:00

Yuuya Tachiki (Department of Biological Sciences, Tokyo Metropolitan University)

Mathematical Modeling for the interpretation of ecological phenomena

Mathematical Models (e.g., dynamical systems) have been used for the interpretation of the ecological phenomena. In this talk, I would like to talk how to utilize mathematical models in the context of the feedback between empirical and theoretical approaches. I would like to propose two approaches from the various ways to utilize mathematical models. The first one is the qualitative prediction by a mathematical model and the validation by experiments. The strength of simple models is the interpretability. Understanding how the model works helps to construct how we can confirm its logic by experiments. The second one is an approach for estimating parameters included in a mathematical model. We are basically interested in phenomena within a range of biologically plausible region in the parameter space. Estimating parameters by experiments should help restricting ourselves within a biologically meaningful range. I, this time, try to explain how to utilize these approaches by giving specific examples of researches of mine.

Mayumi Seto (Faculty of Science, Nara Women's University)

Bioenergetic challenges of understanding the microbial interactions and metabolic evolution

Hydrothermal vents are one of the many likely incubators for the first life on Earth. The recent findings of the metabolic feature of the last universal common ancestor, short for LUCA, that harnesses H2 and CO2, also supports the idea of hydrothermal vents as the location for life's origin. Whereas animals are purely dependent upon aerobic respiration reaction as their energy source, microorganisms can harness a variety of reactions. In general, the energy-harvesting reactions of microbes inhabiting the deep subsurface generate significantly lower energy in comparison with aerobic respiration. Our recent researches based on the bioenergetic population model showed that the survival of microbes in such environments might significantly rely on the mutualistic interactions. I here introduce the basics of bioenergetics, the examples of mutualistic energetic interactions among microbes, and our recent findings on the microbial survival strategies under energetic constraints and how microbes enable them to invade a new environment.

313th 17 January, 2020 (Fri.) 14:00~17:00

Fumitoshi Ishino (Medical Research Institute, Tokyo Medical and Dental University)

Mammalian-specific genomic functions: genomic imprinting and retrotransposon-derived acquired genes

Mammals have evolved a unique viviparous reproductive system and a highly developed central nervous system. How did these unique characteristics emerge in mammalian evolution, and what kinds of changes did occur in the mammalian genomes as evolution proceeded? A key conceptual term in approaching these issues is "mammalian-specific genomic functions", a concept covering both mammalian-specific epigenetics and genetics, such as genomic imprinting and LTR retrotransposon-derived acquired genes, respectively. I will show how they play essential roles in the current mammalian developmental system and discuss how the genomic imprinting mechanism and the acquired genes emerged in the course of mammalian evolution.

Tetsuji Kakutani (Graduate School of Science,The University of Tokyo)

Evolution of sequence-specific anti-silencing systems in Arabidopsis

The arms race between parasitic sequences and hosts is a major driving force for evolution of gene control systems. Since transposable elements (TEs) are potentially deleterious, eukaryotes silence them by epigenetic mechanisms such as DNA methylation. Little is known about how TEs counteract the silencing to propagate during evolution. Here we report behavior of sequence-specific anti-silencing proteins used by Arabidopsis TEs and coevolution of those proteins and their target sequences. Through this coevolution, these TEs propagate with minimum host damage. Our findings provide insight into the evolutionary dynamics of these apparently "selfish" sequences.

312th 20 December, 2019 (Fri.) 14:00~17:00

Naoko Tokuchi (Field Science Education and Research Center)

Social system for Connectivity of hills, humans and oceans

The Field Science Education and Research Center engages in educational and research activities aimed at reinforcing the Connectivity of hills, humans and oceans. In this presentation, I would like to introduce the social cooperation component of the project supported by the Nippon Foundation. The purpose of this project is to clarify the linkage between forests and oceans, and to show the influence of land environmental factors over oceans' biological components and diversity. Even though the research has advanced on these topics, the results must still return back to the society and knowledge sharing is needed. For that reason, we have explored the arrangement of mechanisms/ ways to share the achieved knowledge and to promote the cooperation/coordination between forests and oceans related stakeholders. In this presentation, I would like to explain our effort to reinforce the cooperation between varied stakeholders.

Kazuo Isobe (Graduate School of Agricultural and Life Sciences, The University of Tokyo)

Role of soil microbes in nitrogen cycling and their response to environmental change

Soil microbial communities play critical roles in ecosystem functioning such as carbon transformation, nutrient cycling and plant host defense. The composition of these communities can change over space and time and is sensitive to a variety of global changes, and such shifts can alter their functioning. However, the enormous diversity of soil microbes creates a challenge for a predict understanding of microbial community shift. In this seminar, I will introduce the studies focusing on how seasonal and spatial shift in composition and functions of a soil microbial community can contribute to nitrogen cycling and plant growth in a forest. I will also introduce a phylogenetic approach for predicting how soil microbial communities respond to a variety of global changes.

311th 15 November, 2019 (Fri.) 14:00~17:00

Ko Yasumoto (School of Marine Biosciences, Kitasato University)

Polyamines A biogenic substance for CO2 capture

Polyamines are generally considered low-molecular-weight compounds that have multiple amino groups, are present at high concentrations in the cells of all organisms and are essential for both cell differentiation and proliferation. We recently reported that polyamines can capture CO2 and accelerate bicarbonate/carbonate formation in aqueous solutions. Polyamines may function in the formation of dissolved inorganic carbon reservoir in organisms, which regulates biogenic calcification and photosynthesis. This novel mechanism of CO2 fixation by polyamines adds a new pathway to the global carbon cycle and further suggests a new concept for CO2 removal that could reduce atmospheric CO2 levels and, therefore, global warming.

Keiko Yamaji (Graduate School of Life and Environmental Sciences, University of Tsukuba)

Root-endophytic fungi could enhance metal-tolerance in plants naturally growing at mine sites

Plants naturally growing in mine sites ecologically and physiologically adapt to high concentrations of metals and acidity in the soils. Recently, many researchers have paid attention to root-endophytes, which enhance stress-tolerance in plants. In this presentation, metal-tolerances of Clethra barbinervis and Miscanthus sinensis growing in mine sites will be explained, considering functional root-endophytes. For example, root-endophytes enhanced heavy-metal tolerance in C. barbinervis via the increase of the growth and the decrease of heavy-metal concentrations. Root-endophytes also enhanced aluminum tolerance in M. sinensis via production of siderophore, which can detoxify metals. Therefore, these plants would survive in mine sites, via interactions with root-endophytes symbiotically. Additionally, in this presentation, other research examples showing interactions between plants and root-endophytes will be explained.

Special 24 October, 2019 (Thurs.) 14:00~17:00

Luisa Isaura Falcon Alvarez (Universidad Nacional Autonoma de Mexico)

Bacalar lagoon microbialite reefs

Microbialites are highly diverse bacterial communities that represent modern similes of the oldest life forms, stromatolites (dated >3.5 Ga). Bacalar lagoon, in Mexico, harbors the largest freshwater microbialite occurrences of the world, yet diverse anthropogenic activities are changing the oligotrophic conditions of the lagoon. In this seminar, we will review current research aimed at the exploration of the microbialites in Bacalar lagoon, in order to analyze their microbial genetic diversity and correlate the environmental parameters that structure these communities following a 16S rDNA sequencing approach. Results suggest that there are two main microbialite bioregions associated to gradients in conductivity, bicarbonates, ammonium and NOX. The difference between these microbialite bioregions was further associated with a strong anthropogenic pressure on water quality (agriculture, landfill leachate, lack of water treatment infrastructure and intensive tourism).

Christine L. Weilhoefer (Visiting Associate Professor, Center for Ecological Research, Kyoto University / University of Portland)

The use of microalgae as a bioassessment tool in large-scale aquatic surveys within the United States

Bioassessment is the evaluation of the health of an ecosystem based on the community of organisms that live within it. The bioassessment approach is used by scientists and resource managers around the world to quantitatively measure the ecological health of aquatic ecosystems and to monitor the impacts of stressors on these ecosystems. This seminar will focus on the utility of microalgae in the bioassessment of aquatic ecosystems. Microalgae are ideal organisms for aquatic bioassessment due to their short lifespans, rapid reproduction rate, and sensitivity to a variety of environmental conditions, particularly nutrients. Data from several microalgae-based bioassessments conducted throughout the United States on lakes, streams, wetlands, and coastal areas will be presented.

Special 21 October, 2019 (Mon.) 14:00~17:00

Horst Malchow (Institute of Environmental Systems Research School of Mathematics / Computer Science, Osnabruck University Barbarastr. 12, 49076 Osnabruck, Germany

Functional response of competing residents and invaders to environmental variability

The possible control of competitive invasion by infection of the invader and multiplicative noise is studied. The basic model is the Lotka-Volterra competition system with emergent carrying capacities. Several stationary solutions of the non-infected and infected system are identified as well as parameter ranges of bistability. The latter are used for the numerical study of diffusive invasion phenomena. The Fickian diffusivities, the infection but in particular the white and colored multiplicative noise are the control parameters. It is shown that not only competition, possible infection and mobilities are important drivers of the invasive dynamics but also the noise and especially its color and the functional response of populations to the emergence of noise. The variability of the environment can additionally be modelled by applying Fokker-Planck instead of Fickian diffusion. An interesting feature of Fokker-Planck diffusion is that for spatially varying diffusion coeffcients the stationary solution is not a homogeneous distribution. Instead, the densities accumulate in regions of low diffusivity and tend to lower levels for areas of high diffusivity. Thus, the stationary distribution of the Fokker-Planck diffusion can be interpreted as a refection of different levels of habitat quality [1-5]. The latter recalls the seminal papers on environmental density, cf. [6-7]. Appropriate examples will be presented. References [1] Bengfort, M., Malchow, H., Hilker, F.M. (2016). The Fokker-Planck law of diffusion and pattern formation in heterogeneous media. Journal of Mathematical Biology 73(3), 683-704. [2] Siekmann, I., Malchow, H. (2016). Fighting enemies and noise: Competition of residents and invaders in a stochastically uctuating environment. Mathematical Modelling of Natural Phenomena 11(5), 120-140. [3] Siekmann, I., Bengfort, M., Malchow, H. (2017). Coexistence of competitors mediated by nonlinear noise. European Physical Journal Special Topics 226(9), 2157-2170. [4] Kohnke, M.C., Malchow, H. (2017). Impact of parameter variability and environmental noise on the Klausmeier model of vegetation pattern formation. Mathematics 5, 69 (19 pages). [5] Bengfort, M., Siekmann, I., Malchow, H. (2018). Invasive competition with Fokker-Planck diffusion and noise. Ecological Complexity 34, 134-13. [6] Morisita, M. (1971). Measuring of habitat value by the \environmental density" method. In: Spatial patterns and statistical distributions (Patil, C.D., Pielou, E.C., Waters, W.E., eds.), Statistical Ecology, vol. 1, pp. 379-401. Pennsylvania State University Press, University Park. [7] N. Shigesada, N., Kawasaki, K., Teramoto, E. (1979). Spatial segregation of interacting species. Journal of Theoretical Biology 79, 83-99.

Merlin C. Kohnke (Institute of Environmental Systems Research School of Mathematics / Computer Science, Osnabruck University Barbarastr. 12, 49076 Osnabruck, Germany)

Spatiotemporal patterns in a predator-prey model with Holling type IV functional response

A simple reaction-diffusion predator-prey model with Holling type IV functional response and logistic growth in the prey is considered. The functional response can be interpreted as a group defense mechanism, i.e., the predation rate decreases with resource density when the prey density is high enough [1]. Such a mechanism has been described in diverse biological interactions [2,3]. For instance, high densities of filamentous algae can decrease filtering rates of filter feeders [4]. The model will be described and linked to plankton dynamics. Nonspatial considerations reveal that the predator may go extinct or coexistence (stationary or oscillatory) between predator and prey may emerge depending on the choice of parameters. However, including space, the dynamics are more complex. In particular, spatiotemporal irregular oscillations can rescue the predator from extinction. These oscillations can be characterized as spatiotemporal chaos. Possible underlying mechanisms for this phenomenon will be discussed. References [1] Freedman, H. I., Wolkowicz, G. S. (1986). Predator-prey systems with group defence: the paradox of enrichment revisited. Bulletin of Mathematical Biology, 48(5-6), 493-508. [2] Tener, J. S.. Muskoxen in Canada: a biological and taxonomic review. Vol. 2. Dept. of Northern Affairs and National Resources, Canadian Wildlife Service, 1965. [3] Holmes, J. C. (1972). Modification of intermediate host behaviour by parasites. Behavioural aspects of parasite transmission. [4] Davidowicz, P., Gliwicz, Z. M., Gulati, R. D. (1988). Can Daphnia prevent a blue-green algal bloom in hypertrophic lakes? A laboratory test. Limnologica. Jena, 19(1), 21-26.

310th 18 October, 2019 (Fri.) 14:00~17:00

Osamu Kishida (Field Science Center for Northern Biosphere, Hokkaido University)

Toxicity appeared: exploring the impacts of an alien toad on native amphibians in Hokkaido

Ryoichi Tabata (The origin and history of endemic fishes in Lake Biwa based on molecular genetics)

The origin and history of endemic fishes in Lake Biwa based on molecular genetics

309th 20 September, 2019 (Fri.) 14:00~17:00

Yusuke Saijo (Graduate School of Science and Technology, Nara Institute of Science and Technology)

How do plants recognize and control pathogens and endophytes?

Plants are in nature colonized by a rich diversity of microbial communities, which provide a key basis for plant adaptation to fluctuating environments. Plant-inhabiting microbes range from pathogens, commensals to mutualists, and even change their infection modes depending on the environmental conditions. Indeed, abiotic factors, such as nutrients, humidity or temperature, profoundly influence mutualistic plant-microbe associations and plant disease epidemics. Plant immunity largely relies on cell-surface immune receptors that recognize microbe- or damage-associated signals and intracellular receptors that recognize pathogen-derived virulence effectors. Following a basic framework of the plant immune system and pathogen recognition principles, I will introduce recent studies on the mechanisms by which plants integrate microbial and environmental cues to modulate immune responses and beneficial associations with microbes.

Tokitaka Oyama (Graduate School of Science, Kyoto University)

The circadian system of plants from a cell's point of view

Most organisms have circadian clocks and adapt themselves in the diurnal environments. The circadian clock is a cell-autonomous system and individual cells work as cellular clocks. Time of the clock can be detected by using bioluminescence reporter systems with circadian rhythms. By observing plants/organs/tissues/cells for bioluminescence rhythms, time of the circadian clock can be detected at various hierarchies of plant. Through studies of those circadian rhythms, qualities/precisions of cellular clocks, coordination of circadian behavior in a plant body, synchronization of the clock to day-night cycles have been revealed. Recent results for the circadian system of plants will be introduced.

Special 2 August, 2019 (Wed.) 15:00~16:30

Ji Zhou (Project leader, Earlham Institute (EI), Norwich Research Park (NRP), UK / Professor of Crop Phenomics, Nanjing Agricultural University, China)

Combining machine learning and computer vision to address challenges in multi-scale plant phenotyping for crop improvement

308th 19 July, 2019 (Fri.) 14:00~17:00

Motohiro Hasegawa (Faculty of Science and Engineering, Doshisha University)

The relationships between soil mesofaunal community structures and forest disturbances

Community of soil mesofauna (Collembola, Oribatida etc.) has been studied with the relationships of their feeding habit and decomposition process of litter. The forest disturbances have caused the changes in the community structures of mesofauna. Manipulation studies have been used to clarify the reason of the changes in community structures of mesofauna. I would like to introduce the studies above and discuss about the future study using trait of soil fauna or stable isotope.

Nobuhiro Kaneko (Faculty of Food and Agricultural Sciences, Fukushima University)

Designing conservation agriculture based on soil ecology

Ecological studies in agriculture mostly focused on conservation of organisms in and around croplands, whereas there are only few studies on diversity and agricultural productivity. While, birds and pollinators are major target organisms, soil biodiversity has been ignored. Conservation agriculture is defined as minimal soil disturbance (no-till, NT) and permanent soil cover (mulch) combined with rotations, as a more sustainable cultivation system, and is recommended by FAO for small-scale family based farmers. This management will ecologically enhance soil biodiversity, thus it enable us to maintain stable production with lower cost by using plant-soil feedback. We studied soil food web structures comparing different agricultural management in field manipulation and farmers practices. Modern agriculture largely violates natural nutrient cycling. In order to establish sustainable food production, we propose a method to promote conservation agriculture by evaluating soil ecosystem functioning.

307th 21 June, 2019 (Fri.) 14:00~17:00

Yosuke Toda (Institute of Transformative Bio-Molecules, Nagoya University)

Plant phenotyping via utilization and understanding of representation learning in image quantification

Keisuke Koba (Center for Ecological Research, Kyoto University)

Stable isotope techniques applicable to the ecological studies: recent progress in the methodologies and the future directions

Special 17 April, 2019 (Wed.) 15:00~

Allen Herre (Smithsonian Tropical Research Institute, Panama)

Coevolutionary Vignettes of (Mostly) Mutualistic Interactions

I will discuss the implications of recent empirical advances in our understanding of the evolution and ecology of species interactions, with special reference to the constellation of organisms associated with figs, and the interactions between host plants and their foliar endophytic and arbuscular mycorrhizal fungi (AMF).

Special 10 June, 2019 (Mon.) 14:00~

Michael Bode (Queensland University of Technology)

Creating empirically-validated models of pelagic larval dispersal

Most coral reef fish spend their larval stage dispersing in the open ocean. The distance they travel has important implications for coral reef ecology and conservation, but our current understanding of where larvae go is limited because our data is sparse, and our simulation models are unvalidated. I will outline new methods for validating oceanographic simulations of larval dispersal using genetic parentage assignment datasets. I will then apply them to a case-study of Plectropomus maculatus dispersal from the southern Great Barrier Reef in Australia. A coupled oceanographic-biological model of larval dispersal was constructed for the system, based on our best understanding of the species' behaviour (adult spawning, larval behaviour and ontogeny). This model was parameterised to match an extensive genetic parentage dataset that collected and analysed a large number of adults and juveniles in the system (> 2,000), and positively identified 69 parent-juvenile relationships, over distances of up to 200 km. I will then describe two different examples of how larval dispersal can have a substantial impact on the conservation and management of reef fish metapopulations.

Hiroyuki Yokomizo (National Institute for Environmental Studies)

A new population statistic for comparative plant demography - Inter-stage flow matrix

Population matrix models enable us to derive population statistics that describe the life history characteristics of species or populations such as life expectancy, elasticity and population growth rate. I developed a new population statistic, inter-stage flow matrix, which explicitly describes the inter-stage flows of individuals derived from projection matrices and stable stage distributions. I compared the inter-stage flows of several functional groups using projection matrices from the Plant Matrix Database, COMPADRE version 4.0.1. Inter-stage flows describe distinct demographic properties compared to elasticity and other population statistics. Elasticity describes how a perturbation will influence future population growth rate. In contrast, inter-stage flow directly describes current contributions to population growth rate (at present). Inter-stage flow matrices have potential to provide unique ecological insights that complement other population statistics.

306th 17 May, 2019 (Fri.) 14:00~17:00

Wataru Iwasaki (Graduate School of Science, the University of Tokyo)

Bioinformatics toward "meta"-ecosystem analysis

Daichi Morimoto (Graduate School of Agriculture, Kyoto University)

The interactions between toxic bloom-forming cyanobacteria and its viruses

Special 17 April, 2019 (Wed.) 15:00~

Allen Herre (Smithsonian Tropical Research Institute, Panama)

Coevolutionary Vignettes of (Mostly) Mutualistic Interactions

I will discuss the implications of recent empirical advances in our understanding of the evolution and ecology of species interactions, with special reference to the constellation of organisms associated with figs, and the interactions between host plants and their foliar endophytic and arbuscular mycorrhizal fungi (AMF).

305th 19 April, 2019 (Fri.) 14:00~17:00

Maiko Kagami (Graduate School of Environment and Information Sciences, Yokohama National University)

Fungi in aquatic ecosystems: Diversity, spatial-temporal dynamics and ecosystem functioning

Aquatic ecosystems remain frequently overlooked as fungal habitats, although fungi potentially hold important roles for organic matter cycling and food web dynamics. Molecular analyses of environmental DNA samples have revealed an unexpectedly large diversity of undescribed fungi, so called "dark matter fungi" (DMF). Combining molecular techniques with isolation and microscopic observations are powerful tools, by which we indeed discovered that most of DMF belongs to the novel linages of early diverging branches of the fungal tree of life, i.e. Chytridiomycota. Many of them have zoospores, which can swim in water and utilize various organic matters, including phytoplankton in lakes and oceans. In this talk, I will talk about diversity and spatial-temporal dynamics of aquatic fungi, biological interactions and functioning in biogeochemical cycling.

Takeshi Miki (Faculty of Science and Technology, Ryukoku University)

Feedback between bacterial community assembly and carbon accumulation in aquatic ecosystems

Microbial communities in the ocean are responsible for carbon processes. Microbial carbon pump, proposed by Nianzi Jiao and his colleagues, hypothesizes that bacteria community and trophic interactions within microbial food web are the producer of refractory dissolved organic matter (RDOM) and thus responsible for its accumulation. The likely mechanism is that bacteria physiologically produce RDOM (e.g. compounds to realize stable cell membrane) for maximizing individual survival. In this study, we investigated another mechanism from ecological point of view, especially based on the concepts of community assembly and feedback between community and environment. Through mathematical modeling of bacteria community-carbon cycle feedback and metaanalysis of published data from the ocean, we demonstrated the potential impact of the feedback on carbon accumulation in the ocean.

304th 15 February, 2019 (Fri.) 14:00~17:00

Takaaki Itai (Graduate School of Science, The University of Tokyo)

(I) Geochemical cycle of manganese and arsenic in Lake Biwa

(II) Application of mercury stable isotope ratio for the ecological research

(I) Biogeochemical cycle of Mn and As in bottom of Lake Biwa is of interest because (i) these elements clearly enriches in the surface sediment due to active redox cycle and (ii) spatial distribution of the enriched-layer has been changed since 1970s. Here I present result of geochemical survey including speciation of Mn and As in cored sediment and porewater to model these dynamics near the lake bottom. (II) Mercury stable isotope can be a unique tool in ecological research because it often gives mass-independent fractionation (MIF) via specific photochemical reaction in atmosphere and aquatic environment. This characteristics enable us to examine the depth of MeHg assimilation by aquatic organisms. Here I show an application study using skipjack tuna from North Western Pacific Ocean.

Yasuhiko T. Yamaguchi (Lake Biwa Environmental Research)

Microbial production and degradation of organic nitrogen in aquatic environments indicated by amino acids and nitrogen isotope analysis

Most organic nitrogen in environments exists as detrital nitrogenous material in dissolved and particulate organic matter (DON and PON), which play key roles in nitrogen cycling across multiple aquatic environments such as the ocean and lakes. We have been exploring the use of compound-specific nitrogen isotope ratio of amino acids or enantiomer ratio of amino acids of DON and PON samples as new approaches to examine relative sources, transformation processes, and the potential coupling of these two major forms of N cycle in the aquatic environments. In this seminar, I discuss the roles of heterotrophic microbes in production and degradation of DON and PON based on our recent results.

303rd 18 January, 2019 (Fri.) 14:00~17:00

Keiichiro Tokita (Graduate School of Informatics, Nagoya University)

Species Abundance Distribution of Ecological Networks

In community ecology, the relation between diversity, stability and species abundance distribution (SAD) has been discussed as one of the "unanswered questions in ecology in the last century" (May, 2000)'. In special, theoretical understanding of SAD for a system in a single trophic level has been greatly progressed in the last decade, based on Hubbell's neutral theory. Meanwhile, for more complex systems occurring on multiple trophic levels and including non-neutral species with various types of interspecies interactions among them, a pioneering work by May, which triggered a controversial debate on the relation between diversity and stability, has demonstrated efficacy of a linear analysis and the theory of random matrices. Beyond the linear model, statistical mechanics have been employed for analyzing nonlinear models and have provided global and quantitative information for diversity, stability and SAD. While we have clarified relationships among the strength of the intraspecific competition, asymmetry of interspecies interactions and SAD for a system with fully-connected interactions (Tokita 2004, 2006; Yoshino, Galla and Tokita, 2008; Tokita 2015), we here present that sparse interactions essentially change SAD and it reveals multiple peaks which have been discovered in several field researches but was not demonstrated theoretically (Obuchi, Kabashima and Tokita, 2016). Sparseness of the interspecies interactions, moreover, gives novel non-monotonic dependence of diversity on the ratio of mutualistic interactions, suggesting that the mutualism is not a positive factor for species coexistence in a system with sparse interactions. Since the present theory is based on the general replicator dynamics, the theoretical prediction can be verified not only in community ecology but also in ecological epidemiology, population genetics, game theory, chemical reaction networks, gene regulatory networks and evolution of grammer, etc., and the significance of sparse and mutualistic interactions may give a broad impact on those areas.

Atsushi Mochizuki (Institute for Frontier Life and Medical Sciences, Kyoto University)

Controlling cell fate specification system based on network structure

Modern biology provides many networks describing regulations between bio-molecules. It is widely believed that dynamics of molecular activities based on such regulatory networks are the origin of biological functions. On the other hand, we have a limited understanding for the dynamics of molecular activity based on such complex networks. To overcome these problems, we developed a new theoretical framework (linkage logic theory) with which key nodes for controlling nonlinear dynamics are identified only from network structures without assuming quantitative details, such as functional form, parameter or initial state. According to this theory, the dynamics of a system is controllable to converge on any solution by controlling a subset of nodes called a feedback vertex set (FVS). Here, we applied this theory to a gene regulatory network for the cell fate specification of seven tissues in the ascidian embryo, and found that dynamics of this network consisting of 92 factors are controllable by controlling only five key molecules. By controlling the activities of these key molecules, the specific gene expression of six out of seven tissues observed in the embryo was reproduced. This work is a collaboration with group of Dr. Yutaka Satou, Kyoto University.

302nd 21 December, 2018 (Fri.) 14:00~17:00

Futoshi Nakamura (Graduate School of Agriculture, Hokkaido University)

Current status of Japanese rivers, focusing on habitat environment, ecosystem linkage, and climate change

Hikaru Nakagawa (Field Science Education and Research Center, Kyoto University)

Changes in a stream ecosystem by deer overabundance

Special 19 November., 2018 (Mon.) 10:30~12:30

Stacey Halpern (Professor, Pacific University/Guest Research Associate, Center for Ecological Research, Kyoto University)

Insect herbivore effects on population dynamics of the clonal weed Solanum carolinense

Understanding what determines population size and how it changes over time is a central question in basic plant ecology. It also has important conservation applications to both threatened and invasive species. This project asks whether insect herbivore effects on individual plant fitness also influence plant population dynamics. Herbivores may affect plant populations by altering the population growth rate (λ), a density-independent measure. They may also affect population regulation by changing patterns of density dependence in the plant population. Assessing herbivore effects on density dependence is required to determine whether herbivores affect the equilibrium population size of a plant, a key assumption of biological control efforts and the enemy release hypothesis. We tested the effects of herbivores on population dynamics over four years using experimental populations of Solanum carolinense in its native range. The experimental populations varied in plant density and herbivory, which affected plant size and reproduction; oviposition by a specialist beetle (Leptinotarsa juncta) also increased on plants growing at lower density. Using data from these populations, we parameterized models, and described population dynamics with and without herbivores. Herbivores affected population growth (λ), though effects varied in magnitude and direction among years. Herbivores also altered density dependence, sometimes increasing it and sometimes decreasing it. Finally, herbivores reduced equilibrium plant population size, with effects again varying among years. These results demonstrate that understanding how herbivores contribute to plant population processes like invasions or control of weedy species requires accounting for density dependence, but that herbivore effects on plant population dynamics vary greatly among years. Herbivore effects may also differ in introduced populations in Japan, where preliminary results show lower damage levels than in the US and the loss of a latitudinal gradient in damage.

301st 9 November, 2018 (Fri.) 14:00~17:00

Asano Ishikawa (National Institute of Genetics)

Molecular and genetic basis underlying freshwater colonization and adaptation in sticklebacks

Colonization of empty niches can trigger rapid speciation and adaptive diversification. One of the remarkable examples is the diversification of threespine sticklebacks. After glacial retreats, marine ancestral sticklebacks have colonized newly formed freshwater habitats, resulting morphological, physiological and behavioral diversification. Not all lineages, however, have seized these ecological opportunities to colonize freshwater environments. Here we focused on two stickleback species, threespine stickleback (Gasterosteus aculeatus) and closely related Japan Sea stickleback (G. nipponicus): the former has colonized novel freshwater habitats and diversified, but the latter could not. What molecular and genetic factors determine the difference in the ability to colonize novel niches? In this talk, we will present a key gene responsible for variation in the physiological ability of freshwater colonization and the subsequent adaptation in sticklebacks.

Koji Takayama (Graduate School of Science, Kyoto University)

Global phylogeography of pantropical plants with sea-drifted seeds

Pantropical plants with sea-drifted seeds have an extraordinarily wide range of distribution in littoral areas of the tropics and subtropics worldwide. The global distribution of such plants could be attributed to interactions between geographical barriers and long-distance seed dispersal via ocean currents, which are manifest in species distribution, genetic structuring, and evolutionary history. In this study, I conducted global phylogeographic analyses in two genera, Hibiscus (Malvaceae) and Rhizophora (Rhizophoraceae), to discuss, 1) biogeographic history of species, 2) evolutionary consequences of extreme long-distance seed dispersal, and 3) ecological niches shift of coastal plants.

300th 19 October, 2018 (Fri.) 14:00~17:00

Akira Umehara (Environmental Research Management Center, Hiroshima University)

Dynamics of cyanotoxin in ecosystems

Eutrophication of freshwaters and brackish waters has led to an increase in the occurrence of harmful cyanobacterial blooms in various geographically different areas of the world. Toxic cyanobacteria produce the potent hepatotoxins, microcystins (MCs), which are highly toxic to the livers of mammals, and often promote liver tumors. In this presentation, I'd like to focus on the widespread dispersal and accumulation of MCs in ecosystems of the Isahaya reservoir and its surrounding sea area.

Kanako Ishikawa (Lake Biwa Environmental Research Institute)

Submerged macrophyte management in the South Basin of Lake Biwa

An ecological regime shift from a turbid water state to a clear water state has occurred since 1994 in the South Basin of Lake Biwa. Excessive submerged macrophytes cause oxygen depletion in the bottom layer and cyanobacterial blooms (Aoko) in coastal areas. They can also block pumps and sluices, impede navigation, and cause a decline in the fishery industry and recreational activities. Controlling their proliferation is a major challenge for lake management. We have studied effective removal methods, including the timing of cutting and removal, macrophyte effects on associated organisms, development of a benchmark indicating when management intervention is required and prediction of seasonal growth using a logistic model. Recently, a new problem of filamentous algae has been appearing in areas where the macrophytes have been removed. In this seminar, I discuss the difficulty of managing excessive aquatic plant growth based on our past studies.

299th 21 September., 2018 (Fri.) 14:00~17:00

Yuki Baba (Institute for Agro-Environmental Sciences, NARO)

Effects of environmentally friendly farming on biodiversity and biological control potential in rice paddy ecosystems

Taizo Nakamori (Graduate School of Environment and Information Sciences,Yokohama National University)

Role of sporocarp traits in the interaction between fungi and fungivorous microarthropods

298th 20 July., 2018 (Fri.) 14:00~19:00

Yuma Takahashi (Graduate School of Science, Chiba University)

(1) Linking evolution and ecological functions of genetic diversity

(2) Information design principles for scientific presentation

297th 15 June., 2018 (Fri.) 14:00~17:00

Tomoyuki Saitoh (Tohoku Research Center, Forestry and Forest Products Research Institute)

Gregarious flowering habit and regeneration process of tropical bamboos under the influence of forest fire

Knowledge about life history and reproductive characteristics are recently accumulated in Japan. Little is known about tropical bamboos. We investigated the demography data of culm for the four bamboo species coexist in mixed deciduous forest in Thailand on the period from flowering stage to early regeneration process, and have identified the genet from a clump structure. We have investigated the mortality factors in the reduction curve of genet of bamboo to start the regeneration all at once. Gregarious flowering event of GA and CP was detected by demography data in 1998 and 2001, respectively. GA flowered almost of all genets in 8 of the nine plots. A huge number of genets participated in the flowering event, and died after that. Then, survived genets were observed in all plots. There is a possibility that flowering genets were reproductive or no flowering genets were extant. When the parent genet of them were died, lack of bamboo canopy was occurred, because the next generation start from seed germination. Genet of BT with a large culm began to increase immediately while flowering event have occurred. BT in 6 of nine sub-quadrats was to become the primary dominant species. For the forest fire occurred in 2010, genets with culm >1m high would not be affected by the fire. However, genets with culm only <1m high are affected by the fire.

Takuya Okabe (Graduate School of Integrated Science and Technology, Shizuoka University)

What drives the evolution of phyllotaxis?

Leaf-like appendages of different plant groups are arranged in common patterns categorized into two types: whorled and spiral arrangement, phyllotaxis. The evolutionary cause of this morphological convergence is unknown. While whorled arrangement shows a persistent pattern of alternating whorls of leaves, spiral arrangement entails occasional changes among a sequence of patterns in the course of growth. In the latter, the sequential patterns of mature leaves originate from non-overlapping patterns of nascent leaves characterized with a unique divergence angle 137.5 (degrees). Here I put forward a new view that phyllotaxis is an internal adaptation to a structural constraint rather than an adaptation to environment. Both types of arrangement are caused by a common tendency of leaves to overlap on each other, which is in direct opposition to an intuitive view that leaves avoid overlap to maximize light capture.

296th 18 May., 2018 (Fri.) 14:00~17:00

Shinji Yabuta (Faculty of Life and Environmental Sciences, Teikyo University of Science)

Evolution of motivational conflicting behaviors

When conflicting between two motivations of inconsistent actions, such as an attack and flight, animals often perform a third-party action: displacement actions, ambivalent actions, and/or the autonomic responses. What advantage is there to performing these conflicting behaviors? We are considering that these behaviors have been evolving for better decision-making. In this seminar, I am going to introduce some motivational conflicting behaviors in animals in fighting and then talk about our models to explain the evolution of these behaviors.

Kayoko O. Kameda (Lake Biwa Museum)

Is the Great Cormorant a pest or benefactor?: ecological function and ecosystem services and disservices of the Great Cormorant

The Great Cormorant has ecosystem function of nutrient transportation from aquatic to terrestrial areas by foraging fish in freshwater areas and build a nests on the tree in a forest. Although this function provides supporting and provisioning services by contributing global nutrient cycles and supplying a good organic fertilizer, the Great Comorant also has conflicts with people such as competition over Ayu, the most important fish for present inland fisheries in Japan, and deforestation caused by the breeding activities and the excreta. In order to decrease the conflicts between cormorants and people and enjoy ecosystem services, it is important to clarify the factors causing ecosystem services and disservices and balance between them. In the seminar, I would like to introduce various relationships between cormorants, forests, and people and discuss the factors related to ecosystem services and disservices by the cormorants.

Special 24 April., 2018 (Tues.) 15:00~

Marc T. J. Johnson (Distinguished Visiting Associate Professor, Center for Ecological Research, Kyoto University / University of Toronto, Mississauga)

Evolution in the urban Jungle

Urban areas represent the fastest growing ecosystem on earth, in which the development of cities dramatically changes the biotic and abiotic environment to create novel ecosystems. Despite the importance of urbanization, we have little understanding of how urbanization affects the evolution of species that live in cities. In this talk, I will review our current knowledge of about the effects of cities on multiple evolutionary processes, including mutation, gene flow, genetic drift and natural selection. I will then describe our work examining how these evolutionary processes affect the ability of plants to adapt to urban environments. I will conclude with a discussion of existing gaps in our knowledge and a description of the first global study of urban evolution, in which we are looking for Japanese collaborators.

295th 20 April., 2018 (Fri.) 14:00~17:00

Hitoshi Nakayashiki (Graduate School of Agricultural Science, Kobe University)

Are viruses alive?

"What is life?" is a fundamental question in biology. However, this question is more frequently asked in popular science rather than in academic research. In this seminar, I will ask "What is life?" focusing on viruses. Viruses are generally regarded as a pathogen but they can also be mutualistic with the host. Recent research has revealed that viruses are very diverse in terms of genome size, encoded genes, population, and ecology. Especially, I focus on giant viruses that carry genomic DNA larger than some bacterial genomes, and mutualistic viruses that could have contributed to the evolution of the host.

Kohei Koyama (Obihiro University of Agriculture and Veterinary Medicine)

A lognormal distribution of the lengths of terminal twigs on branches of elm trees

It is well known that the "additive" effect of errors generated the normal (Gaussian) distribution and the "multiplicative" effect of errors generated the lognormal distribution. The sequential breakage model has established a link between sequential processes and lognormal distributions and has been used to explain species abundance distributions. We applied this idea to a tree branch that was generated by a sequential branching process. We tested the hypotheses that the distribution of the lengths of terminal stems of Japanese elm trees (Ulmus davidiana var. japonica), the end products of a sequential branching process, approaches a lognormal distribution. Our results were generally in agreement with the hypothesis. (Koyama et al. 2017 Proc Roy Soc B 284:20162395)

294th 16 February., 2018 (Fri.) 15:00~17:00

Takahiro Irie (Atmosphere and Ocean Research Institute, the University of Tokyo)

Intraspecific variation and larval dispersion of marine benthos

Marine benthos shows a broad life-history variation in the early ontogenetic stage, ranging from the direct development lacking dispersal ability to the indirect development species with a long-time planktonic stage. Their ecological study is still quite preliminary and leaves many unsolved questions, because they are too minute to trace in the field, distribution area is vast, and the total number of individuals is uncountable. Nevertheless, continuing technological progress and low-pricing of DNA-sequencing and parallel computing hardware provide us a good opportunity to address the challenging problems. I will talk about the ongoing project on the planktonic larvae of intertidal cowries and present a future perspective.

293rd 19 January., 2018 (Fri.) 14:00~17:00

Shingo Iwami (Department of Biology, Kyushu University)

New era of ECOEPI in Japan

Since 2016.4.1, we are trying to establish a new feild "Ecological Epidemiology", called ECOEPI(http://ecoepi.jp/), by internationally collaborating with several groups as a vitual network institute. Especially, we are inerested in infectious diseases among human, animal and insect. In this CER seminar, I would like to talk about our activity from the percspective of both pure science and social implementation sience. Specifically, I am going talk about our modeling and prediction study on malaria spread in South Africa, collaboraing with NEKKEN, Nagasaki University. Then, I would like to introduce our developing web application, called "Virtual ECOSYSTEM", in order to tell how ecology and population dynamics, which are basis of our technical approaches, are interesting for non-academic peoples including junior high and high school students. If I have much time, I will talk about our activity to implement Virtual ECOSYSTEM in our society as well.

Tomoki Nakaya (Department of Geography, Ritsumeikan University)

Spatial epidemiology with perspectives on the past, present and future of infectious disease outbreaks in Japan

Spatial epidemiology is a newly emerged field to spatially describe and analyse epidemiological phenomena, particularly about geographical variations in health risks and their association with environmental factors. Spatial analysis has occasionally played a special role to reveal hidden knowledge for controlling diseases in observed epidemiological data, particularly through effective geo-visualization of health risks. In recent days, spatial epidemiology has been substantially advanced by the advent of the geographical information system (GIS), development of various geo-spatial information, and the enhancement of spatial statistics functionalities. Considering another talk focusing on infectious disease ecology in this seminar, I will introduce the approaches of spatial epidemiology with selected topics on the past, present and future of infectious disease outbreaks in Japan. The topics may include historical disease map study on Typhoid fever in early 20th century, modelling of recent infectious disease outbreaks (syphilis or influenza), and estimating future risk distribution of a mosquito-borne disease (Dengue fever) in Japan. With these, I intend to argue on the possibilities and challenges in spatial models, geo-visualization methods, and newly available geographic information, as well as possible applicability of these to the research field of ecology which has developed spatial analysis likewise if time allows.

292nd 15 December., 2017 (Fri.) 14:00~17:00

Kaoru Kitajima (Graduate School of Agriculture, Kyoto University)

Tolerance of the ultimate shade in the understory of tropical moist forests

Shade tolerance is one of the most central concept in ecology of vegetation succession and dynamics of forest communities. Yet, conflicting views exist on the mechanisms that underpin shade tolerance, i.e., what ecophysiological traits explain species differences in shade tolerance. In today's presentation, I will share my research insights from tropical moist forest in Panama, including the long-term monitoring of growth and survival of a seedling cohort of Tachigali versicolor (Fabaceae) for 29 years, a field experiment in which seedlings of several species transplanted in the understory (0.8% of the full sun) received a treatment of additional 90% shade, and comparative analysis of over 60 tree species to link the species differences in seedling survival and their functional traits. A perspective emerging from these studies is that seedling survival in the deep shade of forest understory, where light availability is just about the light compensation point, hinges upon NOT on traits that allow maximization of photosynthetic income and growth rates, but traits that enhance tissue toughness to defend against a broad array of natural enemies, as well as resource storage that enables rapid recover from unfortunate setback caused by accidents and natural enemy attacks.

Makoto Kobayashi (Field Science Center for Northern Biosphere, Hokkaido University)

EEffect of unique disturbance and climate change in cold biome on northern vegetation

Although tundra and boreal forests have important ecosystems function such as huge carbon storage, it is known to be vulnerable for warming climate. To predict the future of structure and function of these vegetation, we still need to enhance our basic understanding how these vegetation in cold biome is maintained. Our group has been investigating the mechanisms through which the soil frost and fire dynamically influence the structure of tundra and boreal forest respectively, with special focus on soil change. It has been demonstrated that time after the severe soil frost creates the gradient of species diversity in tundra vegetation. Furthermore, the growth of regenerating plants in post-fire forest is revealed to be supported by the fire-produced charcoal. In the end, we would like to introduce some latest achievements about the influence of ongoing advancing snowmelt on northern plants, which is being evaluated with large-scale field manipulation in our experimental forest.

291st 17 November., 2017 (Fri.) 14:00~17:00

Masakazu Shimada (Graduate School of Arts and Sciences, University of Tokyo)

Coexistence or extinction?: projection matrix analysis and adaptive evolution in two Anisopteromalus parasitic wasps

Comparing the two closely related parasitic wasps, Anisopteromalus quinarius and A. calandrae, is very interesting to analyze elasticity of the Leslie matrix with phenotypic plasticity. A. calandrae did not show any plasticity of life history parameters because they suck host larvae with straw they made using the ovipositor. On the other hand, A. quinarius showed great phenotypic plasticity of life history parameters, depending on feeding (honey) or not. We analyzed the Leslie matrix and analyzed elasticity of the two species. Competition replacement experiments showed that density-dependent growth rate of A. quinarius could never compete better than A. calandrae. Therefore, coexistence of A. quinarius with A. calandrae in Europa and Northern America widely is suggested due to the niche separations on the primary host insects and their habitats.

Shigeto Dobata (Graduate School of Agriculture, Kyoto University)

Experimental tests of social evolution in insects

In this seminar, I will provide two topics from my recent research: 1) We identified socially parasitic lineage in the parthenogenetic ant Pristomyrmex punctatus. Individuals of the lineage, called "cheaters," reproduce more than workers but never participate in cooperative tasks for their colonies. We experimentally confirmed that the fitness interaction of cheaters and workers meets the conditions of the public goods dilemma. 2) To test how kin selection affects the evolution of competitive traits, an experimental evolution using the adzuki been weevil Callobruchus chinensis is running. Preliminary results support the view that an altruistic trait indeed evolves in the high-relatedness treatment.

290th 20 October., 2017 (Fri.) 14:00~17:00

Yuko Sasaki-Sekimoto (School of Life Science and Technology, Tokyo Institute of Technology)

Evolution and diversity of land plant extracellular lipid

Adaptation of plants to land environments is a crucial point for current prosperity of life on this planet. To understand such land adaptation processes, we focused on a terrestrial alga Klebsormidium nitens (Division Charophyta, Order Klebsormidiales), and reported the draft genome sequence (Hori et. al., Nat commun 2014). Our comparative genome analysis revealed that K. nitens has a set of genes to synthesize cuticular waxes. We chemically analyzed wax components of K. nitens, and found that triacylglycerols (TAGs) and alkanes were the major components. We also investigated aliphatic substances in the cell wall fraction of K. nitens. Many of fatty acids were determined to be lipophilic monomers in K. nitens. Therefore, we propose that K. nitens has a cuticle-like hydrophobic layer composed of lipids and glycoproteins, with a different composition from the cutin polymer typically found in land plant cuticles (Kondo et al., Front Plant Sci. 2016). I compared the composition of cuticular waxes extracted from land plants as well as K. nitens. K. nitens had TAGs on cell walls, and land plants have highly diversified cuticular waxes. I will discuss about the roles of cuticular during land adaptation process of plants.

Kazuyuki Tanaka (Takii & Co., Ltd.)

Traditional vegetable breeding in seed company and application of new breeding technology

Vegetable breeding was started by selecting local landrace which performed better in that region. Hybrid variety were developed to improve its performance based on human demand and economical reason. If we change our viewpoint, we can say that vegetables are the result of evolution by such artificial selection. Now we can apply many new breeding technologies and genome information which lead to accelerate this egoistic procedure. Now it will be possible to create a new vegetable crop ever exist. I will present some examples to show what we achieved by traditional breeding and what happened now in this segment.

289th 15 September., 2017 (Fri.) 14:00~17:00

Richard Karban (Visiting Professor, Center for Ecological Research, Kyoto University / Department of Entomology and Nematology, UC Davis)

What can plant biologists learn about communication from animals?

Animal communication and behavior are far better understood than similar processes in plants. Plants lack central nervous systems but nonetheless face similar selection pressure to sense their environments and to respond appropriately. Human behaviorists differentiate between judgment and decision making. This distinction may also be useful for plants. Plants that do not respond appropriately may err in judgment or decision making.

Animals and plants differ in other important ways. Plants tend to be less mobile; instead of fleeing, they redistribute defenses or valuable resources. Plants tend to be made up of redundant, modular organs; this allows them to be better able at accomplishing multiple tasks simultaneously. Plants can generally tolerate attack and loss of tissues better than animals; this makes induced defenses a more profitable strategy for plants than for animals.

Junji Takabayashi (Center for Ecological Research, Kyoto University)

A novel enzyme secreted from spinnerets of feeding silkworms hampers green leaf volatile production in mulberry leaves

In response to herbivory, plants emit volatile organic compounds, such as green leaf volatiles (GLVs) and volatiles terpenoids that attract carnivorous natural enemies of herbivores. The attraction was called induced indirect defense of plants against herbivores. Since the attraction of natural enemies is maladaptive to currently infesting herbivores, it is likely that herbivores have evolved to suppress the production of such volatiles to make themselves more inconspicuous to natural enemies. However, this possibility has not yet been tested. Here, we clarified this in a tritrophic system of mulberry plants, silkworms and parasitoid flies, Zenillia dorosa. Silkworms suppressed the GLV production in mulberry leaves by using a novel enzyme in the spinneret secretion, and its function was only for this suppression. The suppression made silkworms less conspicuous to the parasitoid flies. This study showed that herbivorous insects could manipulate induced-indirect defense in plants.

Stable Isotope Ecology seminar (open) 27 July., 2017 (Thur.) 14:00~15:30

Erik Hobbie (University of New Hampshire, http://www.eos.sr.unh.edu/Faculty/Hobbie)

Isotopic Explorations of Fungal Functioning in Ecosystems

Fungi are ubiquitous in terrestrial ecosystems, with many either being key decomposers (saprotrophs) or forming symbioses with many of the dominant plants of temperate, boreal, and tundra ecosystems (ectomycorrhizal fungi). In this latter function, fungi receive carbon as sugars and in return supply nutrients to their host plants, with fungi differing greatly in their exploration strategies and enzymatic capabilities. Here, we explore fungal functioning using stable isotope (C and N) and radiocarbon measurements, including: (1) saprotrophic lawn fungi as integrators of competition between C3 and C4 grasses in lawns, (2) wood decay fungi partitioning resources among species based on the age of the wood being assimilated; (3) fungivorous small mammals preserving a signal of organic nitrogen uptake by fungi in their hair, and (4) linking exploration type in ectomycorrhizal fungi to enzymatic capabilities, carbon demand, and where fungi are active in the soil profile.

288th 21 July., 2017 (Fri.) 14:00~17:00

Ryutaro Goto (Seto Marine Biological Laboratory, Field Science Education and Research Center, Kyoto University)

Evolution and adaptation in commensal clams

Symbiotic associations between animals are common and abundant in the sea and play an important role in generation and maintenance of marine biodiversity. The Galeommatidae is a group of small clams that exhibits tremendous diversity in the intertidal zone and is the most species-rich family among the Bivalvia. Interestingly, many members of this family are commensals associated in highly specific relationships with benthic invertebrates, such as crustaceans, annelids and echinoderms, that burrow in soft sediments. I will talk about their evolutionary transitions between commensal and free-living lifestyles, diversification pattern involving host shifts across phyla, and morphological adaptations to each host association.

Taisuke Kanao (Graduate School of Human and Environmental Research, Kyoto University)

Biodiversity and evolution of termitophilous rove beetles

Termite colonies host many other insects that are commonly referred to as termitophiles. A large number of termitophiles have evolved within the beetle family Staphylinidae, especially in lineages of the subfamily Aleocharinae. The termitophilous robe beetles generally have species-specific relationships with their host termites and exhibit unique morphology such as physogastric and limuloid body plans. Most termitophilous rove beetles, together with termites, are distributed in tropical regions, although many countries within these regions remain poorly studied. I performed faunal surveys in several tropical regions to clarify the species diversity of termitophiles and to get materials for further phylogenetic study. I will present the result of taxonomic works and molecular phylogeny of termitophilous species in Aleocharinae as well as the current knowledge on their basic ecology.

287th 16 June., 2017 (Fri.) 14:00~17:00

Kazuya Kobayashi (Field Science Education and Research Center, Kyoto University)

Selfish genes establish complex community

In the Origin of Species, Darwin discussed one of the challenges that workers of eusocial insects presented to his theory of natural selection. The natural selection theory predicted that traits producing more children will spread throughout the population, but in social insects such as ants and bees, very few individuals (queens) in the nest only reproduce, and many other individuals (workers) do not produce offspring by themselves. Why this sterility can be spread in some lineages of Hymenoptera? This challenge was solved by Hamilton in 1964. His breakthrough was to realize that the gene coding sterility can be transmit to the next generation through the reproduction of relatives. Thus, he showed that natural selection does not maximize number of offspring but that of genes. This expanded theory of natural selection, called as kin selection theory, has been supported by diverse aspects of social organisms. One of the strong evidences is female-biased investment by workers in the eusocial Hymenoptera where relatedness to sisters is higher than to brothers due to haplodiploidy. In recent years, there has been an increasing debate over whether the evolution of altruism is better understood using kin selection. Difficulty to test the theory in diplodiploidy is a potential source of doubts about generality of the theory. In the seminar, I introduce our research where we expanded the kin selection theory to explain biased sex allocations of diplodiploidy. Our model predicts that allocation will be biased towards the sex that contributes more of its genes to the next generation only when sex-asymmetric inbreeding occurs. The prediction matches well with the empirical sex allocation of Reticulitermes termites. Our findings indicated that diplodiploidy organisms also maximize number of their genes due to kin selection. I also introduce my recent research focusing on biological community, which showed that, even in this scale that is over species differences, the principal factor creating biological patterns will be the evolutionary force on genes.

Shinya Shoda (Nara National Research Institute for Cultural Properties / BioArCh, University of York)

Organic residue analysis for the reconstructing of cuisine in the coastal area of the Japan Sea during the Holocene sea level rise

Investigating the use of natural resources and foodways of people in the past are important topic in archaeology. In these decades, mostly in UK, organic residue analysis of pottery has been widely applied to understand what kind of food were processed using pottery, that is frequently found through excavations. In Japan, our previous study revealed that in Torihama site in Fukui prefecture, from the Late Pleistocene to mid Holocene (14k to 5k BP), pottery was predominantly used for cooking marine and freshwater resources despite environmental and socio-economic change. Here, to test whether this pattern is applicable for other sites, Torihama was compared with other four sites (8k-6k BP) located coastal area of the Japan Sea. 143 potsherds and 78 adhered organic materials were analyzed by GC-MS and GC-c-IRMS. As a result, frequent existence of aquatic biomarkers, high SRR diastereomer ratio in phytanic acid, as well as relatively high carbon stable isotope ratio of specific fatty acids corresponding to modern/archaeological marine organisms were observed, that are reliably support the intensity of aquatic resource processing in these pottery. This pattern contrasts strongly with that of other Eurasian prehistoric cultures such as in Europe and Middle East, which helps us to understand the diversity of use of natural resource and foodways in global scale.

286th 19 May., 2017 (Fri.) 14:00~17:00

Karel simek (Biology Centre AS CR, Hydrobiological Institute)

Community dynamics of bacteria and bacterivorous flagellates modulates carbon flow to higher trophic levels in freshwater ecosystems

Small protists, largely heterotrophic flagellates, are considered to be the major link connecting dissolved organic material, bacteria and the grazer food chain in aquatic ecosystems. We are now facing a paradox in contemporary microbial ecology: high throughput molecular techniques have provided detailed insights into bacterioplankton community composition, but this is in sharp contrast to our knowledge concerning the ultimate fate of particular bacterial groups. Ignorance of dynamics, both bottom-up and top-down induced, translates into the discovery of high proportions of particular lineages in freshwater bacterioplankton but this may not imply that these bacterial groups grow rapidly or play an important role in carbon flow to higher trophic levels. Selective grazing of flagellates on bacteria has been suggested to modulate bacterioplankton community composition. However, the flagellate predator-bacterial prey relationships are so flexible that changes in the prey community, vice versa, may induce extremely rapid changes in the flagellate predator community as well. We show that the rapid flagellate growth, as detected by their feeding on different bacteria, tightly corresponds to doubling times for rapidly growing bacterioplankton groups. Notably, different bacterioplankton species likely represent different food quality resources for flagellate communities, affecting their growth, community dynamics and carbon flow to higher trophic levels. However, our knowledge of these essential aspects of carbon dynamics in plankton environments is quite limited. In this seminar, I present our research on the flagellate predator-bacterial prey trophic interactions, efficiency of carbon transfer from relevant bacterioplankton groups to the predators, and some novel techniques allowing us to study these trophic interactions at a high taxonomic resolution. We propose a conceptual model explaining the strong linkages between rapid bacterial community shifts and succeeding flagellate predator community shifts, which optimize prey utilization rates and carbon flow from various bacteria to the microbial food chain.

Luisa I. Falcon Alvarez (Visiting Professor, Center for Ecological Research, Kyoto University / Professor, Universidad Nacional Autonoma de Mexico)

Biogeography and phylogeny of Synechococcus: Lake Biwa and Mexican lakes, home of sister groups

Cyanobacteria have evolved to be one of the most diverse and ancient groups of bacteria on Earth. They contribute significantly to global primary production via photosynthesis and some in addition to the nitrogen cycle via nitrogen (N2) fixation. Cyanobacteria are common components of aquatic ecosystems, responsible for ~40% of global CO2 fixation. Genome scale analysis suggests that oxygenic photosynthesis evolved early in the cyanobacterial radiation. The capacity to use water as electron donor in oxygenic photosynthesis, with its consequent generation of free oxygen, most likely appeared by 2,700 million years ago (MYA). Picocyanobacteria are common in lakes and oceans, where Synechococcus are amongst the dominant genera. Synechococcales are a non-monophyletic diverse group comprising both unicellular and filamentous forms, all with parietal thylakoids. Although the ecological relevance of this group is widely acknowledged, questions regarding the phylo-genesis of Synechococcus remain unclear. So far we know that there are endemic Synechococcus, whereas other members of the genus relate to environmental parameters including salinity, and certain species are widely distributed, while others are constrained. Recent advances in the field have suggested that Synechococcus form clades with specificity to oceanic, epilimnetic saline and freshwater ecosystems. Interestingly, Lake Biwa Synechococcus isolates are closely related to strains from Lake Atexcac in central Mexico. Both lakes are freshwater, P-limited environments that sustain large populations and diversity of picocyanobacteria, including Synechococcus. The Biwa/Atexcac cluster is further associated to subalpine lake Synechococcus, as well as to high altitude Patagonian lakes. The vast genetic dispersal of certain Synechococcus strains makes them an excellent model to study both biogeographic patterns in microorganisms and adaptation mechanisms from closely related picocyanobacteria inhabiting a vast geographical and environmental range. I will discuss the proposed approach to work with Synechococcus from different ecogeographic regions as a model to help explain the phylogenetic relationships in the group, as well as ecological parameters related to s diversity. The study models are Synechococcus from Lake Biwa as well as other strains from Mexican lakes. We want to understand the life history behind similar Synechococcus strains retrieved from highly different environments. This study aims to unravel what are the contributing factors that explain co-occurrence of Synechococcus from distant environments and if there are other components of the bacterioplankton assemblage also shared between geographically distant sites.