Researchers Database

TAKASU Fugo

    Vice President Vice President
    Faculty Division of Natural Sciences Research Group of Environmental Sciences Professor
    International Exchange Center Director, International Exchange Center
Contact:
taasues.nara-wu.ac.jp
Last Updated :2021/06/02

researchmap

Degree

  • Doctor of Science, Kyoto University

Research Interests

  • Mathematical and computational study on population and evolutionary dynamics (Mathematical modeling).\nPoint pattern dynamics, evolutionary games, stochastic population dynamics applied to biological conservation. 

Research Areas

  • Life sciences, Biophysics

Research Experience

  • Jan. 2007, Professor
  • Nov. 2000 Dec. - 2006, Associate Professor
  • Jan. 1997 Nov. - 2000, Lecturer
  • Sep. 1994 Dec. - 1996, Research Assistant
  • Apr. 1994 Aug. - 1994, JSPS Research Fellow

Education

  • Apr. 1990, Aug. - 1994, Kyoto University, Graduate School, Division of Natural Science, 生物物理学
  • Mar. - 1990, Kyoto University, Faculty of Science, Department of Biophysics

Committee Memberships

  • 20022003Ecological Society of Japan近畿地区会事務局幹事
  • Japan Society of Mathematical Biology運営委員
  • Ornithological Society of Japan英文誌編集委員、広報委員

Awards

  • The Akira Okubo Prize, The Society for Mathematical Biology and the Japanese Society for Mathematical Biology, Jul. 2007
  • Ecological Research Award 2007, Ecological Society of Japan, Mar. 2007

Published Papers

  • Asymptotic behaviors of stochastic epidemic models with jump-diffusion

    Nguyen Thanh Dieu; Takasu Fugo; Nguyen Huu Du

    Elsevier BV, Oct. 2020, Applied Mathematical Modelling, 86, 259 - 270, doi

    Scientific journal

  • Rumination Behavior Difference During Rutting Season Between Cervus nippon nippon in Japan and Elaphurus davidianus in Dafeng

    Zhang Yigui; Ullah Sana; TAKASU Fugo; Li Zhongqiu

    Jan. 2020, Journal of Sichuan University (Engineering Science Edition), 39, 50 - 55

  • マツ枯れ進展における潜在感染木の役割に関する数理的研究

    TAKASU Fugo

    Jan. 2019, 日本森林学会誌101巻1号30-34, 101 (1), 30-34, doi

  • Equilibrium properties of the spatial SIS model as a point pattern dynamics - How is infection distributed over space?

    TAKASU Fugo

    2019, Journal of Theoretical Biology, 468, 12-26, doi

  • How can distinct egg polymorphism be maintained in the rufescent prinia (Prinia rufescens)-plaintive cuckoo (Cacomantis merulinus) interaction-a modeling approach

    Wei Liang; Canchao Yang; Fugo Takasu

    In avian brood parasitism, both the host and the parasite are expected to develop various conflicting adaptations; hosts develop a defense against parasitism, such as an ability to recognize and reject parasitic eggs that look unlike their own, while parasites evolve egg mimicry to counter this host defense. Hosts may further evolve to generate various egg phenotypes that are not mimicked by parasites. Difference in egg phenotype critically affects the successful reproduction of hosts and parasites. Recent studies have shown that clear polymorphism in egg phenotype is observed in several host-parasite interactions, which suggests that egg polymorphism may be a more universal phenomenon than previously thought. We examined the mechanism for maintaining egg polymorphism in the rufescent prinia (Prinia rufescens) that is parasitized by the plaintive cuckoo (Cacomantis merulinus) from a theoretical viewpoint based on a mathematical model. The prinia has four distinct egg phenotypes: immaculate white, immaculate blue, white with spots, and blue with spots. Only two egg phenotypes, white with spots and blue with spots, are found in the cuckoo population. We show that the observed prinia and cuckoo phenotypes cannot be at an equilibrium and that egg polymorphism can be maintained either at stationary equilibrium or with dynamic, frequency oscillations, depending on the mutation rates of the background color and spottiness. Long-term monitoring of the prinia-cuckoo interaction over a wide geographic range is needed to test the results of the model analyses., WILEY, Aug. 2017, ECOLOGY AND EVOLUTION, 7 (15), 5613 - 5620, doi;web_of_science

    Scientific journal

  • Spatially explicit model applied to pine wilt disease dispersal based on host plant infestation

    Tuyen Van Nguyen; Young-Seuk Park; Chang-Sik Jeoung; Won-Il Choi; Yong-Kuk Kim; Il-Hyo Jung; Nanako Shigesada; Kohkichi Kawasaki; Fugo Takasu; Tae-Soo Chon

    Pine wilt disease is a serious pest for pine trees in many countries, especially in Asia (e.g., South Korea, Japan, China and Taiwan). In this study, we characterised dispersal patterns (e.g., direction and area) of pine wilt disease in the southern part of Korea in four-year period based on the cross-correlation function. The most likely distance of the highest infestation probability after one year is around 1.2 km from the disease source according to the distribution of pairwise distance. Subsequently, a spatially explicit model was developed in two dimensions by incorporating biological and environmental events, including influence of infested neighbourhoods, short- and long-distance dispersal, asymptomatic carriers and typhoon. The model results were in good agreement with field data when evaluated using the receiver operating characteristics and pair-correlation functions. Asymptomatic carrier played an important role in the spread of PWD. The infestation probabilities based on the spatially explicit model provided the map of spatial conformations that would be effective in addressing disease occurrence in both local and global aspects. (C) 2016 Elsevier B.V. All rights reserved., ELSEVIER SCIENCE BV, Jun. 2017, ECOLOGICAL MODELLING, 353, 54 - 62, doi;web_of_science

    Scientific journal

  • Disappearance of eggs from nonparasitized nests of brood parasite hosts: the evolutionary equilibrium hypothesis revisited

    Bard G. Stokke; Eivin Roskaft; Arne Moksnes; Anders Pape Moller; Anton Antonov; Frode Fossoy; Wei Liang; German Lopez-Iborra; Csaba Moskat; Jacqui A. Shykoff; Manuel Soler; Johan R. Vikan; Canchao Yang; Fugo Takasu

    The evolutionary equilibrium hypothesis was proposed to explain variation in egg rejection rates among individual hosts (intra- and interspecific) of avian brood parasites. Hosts may sometimes mistakenly reject own eggs when they are not parasitized (i.e. make recognition errors). Such errors would incur fitness costs and could counter the evolution of host defences driven by costs of parasitism (i.e. creating equilibrium between acceptors and rejecters within particular host populations). In the present study, we report the disappearance of host eggs from nonparasitized nests in populations of seven actual and potential hosts of the common cuckoo Cuculus canorus. Based on these data, we calculate the magnitude of the balancing parasitism rate provided that all eggs lost are a result of recognition errors. Importantly, because eggs are known to disappear from nests for reasons other than erroneous host rejection, our data represent the maximum estimates of such costs. Nonetheless, the disappearance of eggs was a rare event and therefore incurred low costs compared to the high costs of parasitism. Hence, costs as aresult of recognition errors are probably of minor importance with respect to opposing selective pressure for theevolution of egg rejection in these hosts. We cannot exclude the possibility that low or intermediate egg rejection rates in some host populations may be caused by spatiotemporal variation in the occurrence of parasitism and gene flow, creating a variable influence of opposing costs as a result of recognition errors and the costs of parasitism., WILEY-BLACKWELL, Jun. 2016, BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, 118 (2), 215 - 225, doi;web_of_science

    Scientific journal

  • Modeling the cuckoo's brood parasitic behavior in the presence of egg polymorphism

    Wei Liang; Canchao Yang; Fugo Takasu

    The common cuckoo Cuculus canorus is a brood parasite that utilizes many host species. These have evolved defense against parasitism to reject cuckoo eggs that look unlike their own and some cuckoos have evolved egg mimicry to counter this defense. Egg phenotype indeed plays a key role for both the cuckoo and its hosts to successfully reproduce. It has been argued that cuckoos should parasitize host nests where egg phenotype matches because this makes parasitism more successful. Details of the cuckoo's parasitic behavior, however, largely remains unknown if they really parasitize hosts depending on "egg matching". In this paper, we model a time sequence of parasitic events in which a cuckoo finds host nests and decides to parasitize them or not in the presence of egg polymorphism. We evaluate which strategy is optimal: (1) opportunistic parasitism where cuckoos parasitize hosts irrespective of the phenotype, or (2) non-opportunistic parasitism where cuckoos parasitize hosts where egg phenotype matches. The analysis showed that either of the two strategies can be optimal. Factors not considered in the model, e.g., ecological and evolutionary changes both in the cuckoo and the host side, are discussed to explain apparent contrasts observed in some cuckoo-host interactions., SPRINGER JAPAN KK, May 2016, JOURNAL OF ETHOLOGY, 34 (2), 127 - 132, doi;web_of_science

    Scientific journal

  • Ancient origin and maternal inheritance of blue cuckoo eggs

    Frode Fossoy; Michael D. Sorenson; Wei Liang; Torbjorn Ekrem; Arne Moksnes; Anders P. Moller; Jarkko Rutila; Eivin Roskaft; Fugo Takasu; Canchao Yang; Bard G. Stokke

    Maternal inheritance via the female-specific W chromosome was long ago proposed as a potential solution to the evolutionary enigma of co-existing host-specific races (or 'gentes') in avian brood parasites. Here we report the first unambiguous evidence for maternal inheritance of egg colouration in the brood-parasitic common cuckoo Cuculus canorus. Females laying blue eggs belong to an ancient (similar to 2.6 Myr) maternal lineage, as evidenced by both mitochondrial and W-linked DNA, but are indistinguishable at nuclear DNA from other common cuckoos. Hence, cuckoo host races with blue eggs are distinguished only by maternally inherited components of the genome, which maintain host-specific adaptation despite interbreeding among males and females reared by different hosts. A mitochondrial phylogeny suggests that blue eggs originated in Asia and then expanded westwards as female cuckoos laying blue eggs interbred with the existing European population, introducing an adaptive trait that expanded the range of potential hosts., NATURE PUBLISHING GROUP, Jan. 2016, NATURE COMMUNICATIONS, 7 (10272), doi;web_of_science

    Scientific journal

  • Beyond pairs: Definition and interpretation of third-order structure in spatial point patterns

    Chiho Kaito; Ulf Dieckmann; Akira Sasaki; Fugo Takasu

    Spatial distributions of biological species are an important source of information for understanding local interactions at the scale of individuals. Technological advances have made it easier to measure these distributions as spatial point patterns, specifying the locations of individuals. Extensive attention has been devoted to analyzing the second-order structure of such point patterns by focusing on pairs of individuals, and it is well known that the local crowdedness of individuals can thus be quantified. Statistical measures such as a point pattern's pair correlation function or Ripley's K function show whether a given point pattern is clustered (excess of short-distance pairs) or overdispersed (shortage of short-distance pairs). These notions are naturally defined in comparison with control patterns exhibiting complete spatial randomness, i.e., an absence of any spatial structure. However, there is no rational reason why the analysis of point patterns should stop at the second order. In this paper, we focus on triplets of individuals in an attempt to quantify and interpret the third-order structure of a point pattern. We demonstrate that point patterns with "bandedness", in which individuals are primarily distributed within bands, can be detected by an excess of thinner triplets at a characteristic spatial scale linked to the band's width. In this context, we show how the generation of control patterns as a reference for gauging a test pattern's triplet frequencies is critical for defining and interpreting the third-order structure of point patterns. Since perfect information on a point pattern's second-order structure typically suffices for its unique reconstruction (up to translation, rotation, and reflection), we conjecture that it is essential to minimally coarse-grain such second-order information before using it to generate control patterns for identifying a point pattern's third-order structure. We recommend the further exploration of this conjecture for future studies. (C) 2015 Elsevier Ltd. All rights reserved., ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, May 2015, JOURNAL OF THEORETICAL BIOLOGY, 372, 22 - 38, doi;web_of_science

    Scientific journal

  • Why cuckoos should parasitize parrotbills by laying eggs randomly rather than laying eggs matching the egg appearance of parrotbill hosts?

    Canchao Yang; Fugo Takasu; Wei Liang; Anders P. Moller

    The coevolutionary interaction between cuckoos and their hosts has been studied for a long time, but to date some puzzles still remain unsolved. Whether cuckoos parasitize their hosts by laying eggs randomly or matching the egg morphs of their hosts is one of the mysteries of the cuckoo problem. Scientists tend to believe that cuckoos lay eggs matching the appearance of host eggs due to selection caused by the ability of the hosts to recognize their own eggs. In this paper, we first review previous empirical studies to test this mystery and found no studies have provided direct evidence of cuckoos choosing to parasitize host nests where egg color and pattern match. We then present examples of unmatched cuckoo eggs in host nests and key life history traits of cuckoos, e.g. secretive behavior and rapid egg-laying and link them to cuckoo egg laying behavior. Finally we develop a conceptual model to demonstrate the egg laying behaviour of cuckoos and propose an empirical test that can provide direct evidence of the egg-laying properties of female cuckoos. We speculate that the degree of egg matching between cuckoo eggs and those of the host as detected by humans is caused by the ability of the hosts to recognize their own eggs, rather than the selection of matching host eggs by cuckoos. The case of Common Cuckoos (Cuculus canorus) and their parrotbill hosts (Paradoxornis alphonsianus), where it has been shown that both have evolved polymorphic eggs (mainly blue and white), was used to develop a conceptual model to demonstrate why cuckoos should utilize parrotbill hosts by laying eggs randomly rather than laying eggs matching the appearance of host eggs. In conclusion, we found no evidence for the hypothesis that cuckoos lay eggs based on own egg color matching that of the parrotbill-cuckoo system. We argue theoretically that laying eggs matching those of the hosts in this system violates a key trait of the life history of cuckoos and therefore should be maladaptive., BIOMED CENTRAL LTD, Apr. 2015, AVIAN RESEARCH, 6 (5), doi;web_of_science

  • Population viability analysis of the Japanese rock ptarmigan Lagopus muta japonica in Japan

    Ayaka Suzuki; Atsushi Kobayashi; Hiroshi Nakamura; Fugo Takasu

    The Japanese rock ptarmigan Lagopus muta japonica breeds only in limited alpine areas at high elevations (> 2,500 m a.s.1.) in Japan. The estimated population size is about 2,000 birds and their breeding distribution is subdivided into several local areas, in each of which they may be at risk of local extinction. We estimated age-specific demographic parameters of the core population breeding on Mt. Norikura in Gifu and Nagano prefecture in Japan. We also estimated population viability using deterministic and stochastic population models. Age-specific fertility (the number of female offspring that survived to the next breeding season per female) was 0.417 +/- 0.086, 0.490 +/- 0.080, 0.513 +/- 0.153, 0.435 +/- 0.078, 0.562 +/- 0.139, 0.580 +/- 0.122 (mean SE) for ages 1-6 +, respectively. The annual survival rate was 0.739 +/- 0.047, 0.624 +/- 0.064, 0.513 +/- .087, 0.732 +/- 0.151, 0.447 +/- 0.220, 0.486 +/- 0.089. The population growth rate, evaluated by use of a deterministic projection-matrix model, predicted a stable population, lambda= 1.105 +/- 0.063, 95% CI = 0.985-1.231 and lambda= 1.114 +/- 0.062, 0.996-1.239, using two different assumptions for the final age of reproduction by ptarmigan. We evaluated the risk of extinction as the proportion of Xs that was <= 1, and this was <= 4.4%. To complement the deterministic model, we developed an individual-based stochastic population model in which each of the individuals produced a variable number of offspring and survived one year with certain probabilities that were drawn from estimated distributions of age-specific clutch size and survival rates. Averaged population growth rate under the stochastic model was lambda= 1.1, and the risk of extinction defined as the proportion of trials in which population size <= 1 within 30 years was <= 8.9%, even when the starting population was small (15 birds). These results suggest that the local population at Mt. Norikura is stable in size and suffers a relatively low risk of extinction. We suggest that this population can serve as a potential source for surrounding small local populations that may be sink populations., WILDLIFE BIOLOGY, Dec. 2013, WILDLIFE BIOLOGY, 19 (4), 339 - 346, web_of_science

    Scientific journal

  • Egg arrangement in avian clutches covaries with the rejection of foreign eggs

    Lenka Polacikova; Fugo Takasu; Bard G. Stokke; Arne Moksnes; Eivin Roskaft; Phillip Cassey; Mark E. Hauber; Tomas Grim

    In birds, the colour, maculation, shape, and size of their eggs play critical roles in discrimination of foreign eggs in the clutch. So far, however, no study has examined the role of egg arrangement within a clutch on host rejection responses. We predicted that individual females which maintain consistent egg arrangements within their clutch would be better able to detect and reject foreign eggs than females without a consistent egg arrangement (i.e. whose eggs change positions more often across incubation). We tested this "egg arrangement hypothesis" in blackbirds (Turdus merula) and song thrush (T. philomelos). Both species are suitable candidates for research on egg rejection, because they show high inter-individual variation and individual repeatability in egg rejection responses. As predicted, using our custom-defined metrics of egg arrangement, rejecter females' clutches showed significantly more consistent patterns in egg arrangement than acceptor females' clutches. Only parameters related to blunt pole showed consistent differences between rejecters and acceptors. This finding makes biological sense because it is already known that song thrush use blunt pole cues to reject foreign eggs. We propose that a disturbance of the original egg arrangement pattern by the laying parasite may alert host females that maintain a consistent egg arrangement to the risk of having been parasitized. Once alerted, these hosts may shift their discrimination thresholds to be more restrictive so as to reject a foreign egg with higher probability. Future studies will benefit from experimentally testing whether these two and other parasitized rejecter host species may rely on the use of consistent egg arrangements as a component of their anti-parasitic defence mechanisms., SPRINGER HEIDELBERG, Sep. 2013, ANIMAL COGNITION, 16 (5), 819 - 828, doi;web_of_science

    Scientific journal

  • Dynamic Regulation of Myosin Light Chain Phosphorylation by Rho-kinase

    Takako Kaneko-Kawano; Fugo Takasu; Honda Naoki; Yuichi Sakumura; Shin Ishii; Takahiro Ueba; Akinori Eiyama; Aiko Okada; Yoji Kawano; Kenji Suzuki

    Myosin light chain (MLC) phosphorylation plays important roles in various cellular functions such as cellular morphogenesis, motility, and smooth muscle contraction. MLC phosphorylation is determined by the balance between activities of Rho-associated kinase (Rho-kinase) and myosin phosphatase. An impaired balance between Rho-kinase and myosin phosphatase activities induces the abnormal sustained phosphorylation of MLC, which contributes to the pathogenesis of certain vascular diseases, such as vasospasm and hypertension. However, the dynamic principle of the system underlying the regulation of MLC phosphorylation remains to be clarified. Here, to elucidate this dynamic principle whereby Rho-kinase regulates MLC phosphorylation, we developed a mathematical model based on the behavior of thrombin-dependent MLC phosphorylation, which is regulated by the Rho-kinase signaling network. Through analyzing our mathematical model, we predict that MLC phosphorylation and myosin phosphatase activity exhibit bistability, and that a novel signaling pathway leading to the auto-activation of myosin phosphatase is required for the regulatory system of MLC phosphorylation. In addition, on the basis of experimental data, we propose that the auto-activation pathway of myosin phosphatase occurs in vivo. These results indicate that bistability of myosin phosphatase activity is responsible for the bistability of MLC phosphorylation, and the sustained phosphorylation of MLC is attributed to this feature of bistability., PUBLIC LIBRARY SCIENCE, Jun. 2012, PLOS ONE, 7 (6), e39269. doi:10.1371/journal.po, doi;web_of_science

    Scientific journal

  • Modelling the maintenance of egg polymorphism in avian brood parasites and their hosts

    W. Liang; C. Yang; B. G. Stokke; A. Antonov; F. Fossoy; J. R. Vikan; A. Moksnes; E. Roskaft; J. A. Shykoff; A. P. Moller; F. Takasu

    In avian brood parasitism, egg phenotype plays a key role for both host and parasite reproduction. Several parrotbill species of the genus Paradoxornis are parasitized by the common cuckoo Cuculus canorus, and clear polymorphism in egg phenotype is observed. In this article, we develop a population genetics model in order to identify the key parameters that control the maintenance of egg polymorphism. The model analyses show that egg polymorphism can be maintained either statically as an equilibrium or dynamically with frequency oscillations depending on the sensitivity of the host against unlike eggs and how the parasite targets host nests with specific egg phenotypes. On the basis of the model, we discuss egg polymorphism observed in parrotbills and other host species parasitized by the cuckoo. We suggest the possibility that frequencies of egg phenotypes oscillate and we appeal for monitoring of cuckoohost interactions over a large spatiotemporal scale., WILEY-BLACKWELL, May 2012, JOURNAL OF EVOLUTIONARY BIOLOGY, 25 (5), 916 - 929, doi;web_of_science

    Scientific journal

  • Sex roles in egg recognition and egg polymorphism in avian brood parasitism

    Wei Liang; Canchao Yang; Anton Antonov; Frode Fossoy; Bard G. Stokke; Arne Moksnes; Eivin Roskaft; Jacqui A. Shykoff; Anders P. Moller; Fugo Takasu

    Avian brood parasites impose strong selection on their hosts leading to the evolution of antiparasite defenses like egg recognition and rejection. Discordance and template-based cognitive mechanisms may form the base for egg recognition by hosts. For discordance, hosts recognize eggs that constitute the minority in a clutch as alien, whereas in template-based recognition, hosts recognize eggs as alien when they do not match a template that can be innate or learnt. Template-based recognition by learning can be compromised in host species with polymorphic egg color like Paradoxornis parrotbills, hosts of the common cuckoo Cuculus canorus, because a male that learns an egg color in his first breeding attempt can subsequently mate with females having different colors and therefore reject his own eggs. We present a simple conceptual model to understand how an asymmetry in sex roles of care for eggs and egg polymorphism influence the evolution of egg recognition by hosts. We derive host reproductive success in the presence of variation in egg phenotype for both host and parasite. Our model shows that male recognition by learning is disadvantageous unless the host has monomorphic eggs. We suggest that interclutch variation in egg phenotype is the key to understanding the evolution of egg recognition and the sex involved., OXFORD UNIV PRESS INC, Mar. 2012, BEHAVIORAL ECOLOGY, 23 (2), 397 - 402, doi;web_of_science

    Scientific journal

  • Development of an individual-based simulation model for the spread of citrus greening disease by the vector insect Diaphorina citri

    TAKASU Fugo; Youichi Kobori; Fugo Takasu; Yasuo Ohto

    2012, Zoology, Dr. Mar?a-Dolores Garc?a (Ed.), ISBN: 978-953-51-0360-8, InTech, 87-102

  • Cuckoo parasitism on two closely-related Acrocephalus warblers in distant areas: a case of parallel coevolution?

    TAKASU Fugo; Csaba Mosk?t; Fugo Takasu; A. Roman Mu?oz; Hiroshi Nakamura; Mikl?s B?n; Zolt?n Barta

    2012, Chinese Birds, 3 (4), 320-329, doi

  • 日本におけるコウノトリの再導入個体群の存続可能性分析

    TAKASU Fugo

    2012, 野生復帰, 2, 1-6

  • The analysis of common cuckoo's egg shape in relation to its hosts' in two geographically distant areas

    M. Ban; Z. Barta; A. R. Munoz; F. Takasu; H. Nakamura; C. Moskat

    Evolutionary adaptations are required by common cuckoos Cuculus canorus to match host eggs. Hosts may discriminate against alien eggs; hence, accurate matching of the parasite egg to the hosts' is essential. Egg shape is the least-studied component of egg mimicry, and it may also have other functions: an optimal egg shape is necessary for effective incubation. For this reason, cuckoo eggs may show a wide range of variations in shape to a set of host species. Here, we compare cuckoo and host eggs by using egg shape parameters in two distant areas: from the nests of great reed warblers Acrocephalus arundinaceus, robins Erithacus rubecula and marsh warblers Acrocephalus palustris in Hungary, and oriental reed warblers Acrocephalus orientalis, bull-headed shrikes Lanius bucephalus and black-faced buntings Emberiza spodocephala from Japan. Our results suggest the lack of evolutionary adaptation of different cuckoo gentes to their corresponding hosts in terms of egg shape. However, our analyses revealed that cuckoo eggs showed a geographical difference in egg shape., WILEY-BLACKWELL, Jun. 2011, JOURNAL OF ZOOLOGY, 284 (2), 77 - 83, doi;web_of_science

    Scientific journal

  • Isolation by time and habitat and coexistence of distinct host races of the common cuckoo

    A. P. Moller; A. Antonov; B. G. Stokke; F. Fossoy; A. Moksnes; E. Roskaft; F. Takasu

    Isolation by time occurs when different populations of a single species reproduce at different times and thereby reduce the probability of interbreeding, potentially causing divergent adaptation to timing of reproduction, eventually resulting in ecological species separated by timing of reproduction. We analysed extensive data on timing of reproduction by different host races of the common cuckoo Cuculus canorus that is an obligate brood parasite laying eggs in the nests of many different species of passerine birds. Because different hosts breed at different times, specific host races of cuckoos have adapted to specific hosts by laying eggs when nests of these hosts are available, and such divergence may be further exaggerated by differences in timing of breeding among host races with similar habitat requirements. Host species accounted for a quarter of the variance in timing of breeding by the cuckoo. Common cuckoos reproduced at a similar, but narrower subset of dates as did possible hosts, showing that only a fraction of hosts with specific breeding dates were parasitized. Common cuckoo eggs laid in the 'right' kind of nests, phenotypically matching the eggs of the host, were laid later during the season than cuckoo eggs laid in the 'wrong' kind of nests where the eggs did not mimic those of the host. Pairs of sympatric cuckoo host races differed more in timing of breeding than pairs of allopatric host races, and pairs of cuckoo host races with similar breeding habitat differed more in breeding date than pairs of cuckoo host races with dissimilar habitat, as expected from reproductive character displacement. These findings are consistent with cuckoo host races being isolated by timing of breeding and habitat., WILEY-BLACKWELL, Mar. 2011, JOURNAL OF EVOLUTIONARY BIOLOGY, 24 (3), 676 - 684, doi;web_of_science

    Scientific journal

  • Dispersal of adult Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), the vector of citrus greening disease, in artificial release experiments

    Youichi Kobori; Tadafumi Nakata; Yasuo Ohto; Fugo Takasu

    Artificial release of marked adult Diaphorina citri, the insect vector of citrus greening disease, was performed in July 2007 (10,000 adults released, experiment 1) and October 2008 (1,000 adults released, experiment 2) to determine the association of the dispersal pattern with disease invasion risk. During the experimental periods, in experiment 1, the mean dispersal distances from the release point were 5-6 m and in experiment 2 they were 6-12 m. Further examination of the relationship between dispersal distance and season is needed. The number of released D. citri declined with increasing distance from the release point and did not change markedly with time. The center of distribution moved little during the experimental period. These results suggest that the adult D. citri barely moved once they had colonized a host plant within a few days after their release. Our results also suggest that the released D. citri moved with the wind. The diffusion coefficient was estimated at 7.23 from experiment 1, but random diffusion might be a poor descriptor of the dispersal of adult D. citri., SPRINGER TOKYO, Feb. 2011, APPLIED ENTOMOLOGY AND ZOOLOGY, 46 (1), 27 - 30, doi;web_of_science

    Scientific journal

  • Modeling the consequence of increased host tolerance toward avian brood parasitism

    Fugo Takasu; Csaba Moskat

    Avian brood parasites greatly reduce the reproductive success of their hosts. Empirical studies have demonstrated that some hosts have evolved defenses against parasitism like an ability to recognize and reject parasitic eggs that are dissimilar to their own eggs. Detailed mechanisms of how hosts recognize parasitism still remain unknown, but recent studies have shown that the host's recognition, in many cases, is based on discordance of the eggs in a clutch, and that hosts are more error-prone when the nest is multiply parasitized, i.e., hosts tend to accept more multiple parasitism than single parasitism. In an area in Hungary, the great reed warbler Acrocephalus arundinaceus, one of the main hosts of the common cuckoo Cuculus canorus, is heavily parasitized and the parasitism rate has been kept at quite a high level for decades. Previous mathematical models suggest that such a high parasitism rate can be maintained because the focal host population behaves as a sink where few hosts can reproduce but immigration from outside replenishes the loss of host reproduction in the sink population. Here, we explore the consequences of the increased host tolerance towards multiple parasitism which has been overlooked in the previous studies using a simple model. Our model analysis shows that the increased host tolerance can dramatically contribute to both the parasite abundance and the parasitism rate being kept at a high level. We suggest that such a host behavior, combined with host immigration, can be an important factor responsible for the observed severe parasitism., SPRINGER JAPAN KK, Jan. 2011, POPULATION ECOLOGY, 53 (1), 187 - 193, doi;web_of_science

    Scientific journal

  • Coevolution in Action: Disruptive Selection on Egg Colour in an Avian Brood Parasite and Its Host

    Canchao Yang; Wei Liang; Yan Cai; Suhua Shi; Fugo Takasu; Anders P. Moller; Anton Antonov; Frode Fossoy; Arne Moksnes; Eivin Roskaft; Bard G. Stokke

    Background: Trait polymorphism can evolve as a consequence of frequency-dependent selection. Coevolutionary interactions between hosts and parasites may lead to selection on both to evolve extreme phenotypes deviating from the norm, through disruptive selection. Methodology/Principal finding: Here, we show through detailed field studies and experimental procedures that the ashy-throated parrotbill (Paradoxornis alphonsianus) and its avian brood parasite, the common cuckoo (Cuculus canorus), have both evolved egg polymorphism manifested in discrete immaculate white, pale blue, and blue egg phenotypes within a single population. In this host-parasite system the most common egg colours were white and blue, with no significant difference in parasitism rates between hosts laying eggs of either colour. Furthermore, selection on parasites for countering the evolution of host egg types appears to be strong, since ashy-throated parrotbills have evolved rejection abilities for even partially mimetic eggs. Conclusions/Significance: The parrotbill-cuckoo system constitutes a clear outcome of disruptive selection on both host and parasite egg phenotypes driven by coevolution, due to the cost of parasitism in the host and by host defences in the parasite. The present study is to our knowledge the first to report the influence of disruptive selection on evolution of discrete phenotypes in both parasite and host traits in an avian brood parasitism system., PUBLIC LIBRARY SCIENCE, May 2010, PLOS ONE, 5 (5), e10816. doi:10.1371/journal.po, doi;web_of_science

    Scientific journal

  • Adaptations in the common cuckoo (Cuculus canorus) to host eggs in a multiple-hosts system of brood parasitism

    Fugo Takasu; Csaba Moskat; A. Roman Munoz; Sadao Imanishi; Hiroshi Nakamura

    The common cuckoo Cuculus canorus parasitism greatly reduces the reproductive success of its hosts and imposes strong selection pressure for hosts to evolve defences against parasitism, such as the ability to recognize and reject dissimilar parasitic eggs, which, in turn, selects for better egg mimicry by the cuckoo. In the co-evolutionary interaction, however, it remains unknown how the cuckoo successfully expanded its range of host usage and how they developed egg mimicry. Most previous studies were conducted in areas where a very few number of host species (i.e. one or two at most) are sympatric with the cuckoo. Several host species, however, breed sympatric with the cuckoo and have been parasitized in the study site in Nagano, central Japan. Such a multiple-hosts system will provide valuable insights for understanding the cuckoo-hosts interactions in the past. In the present study, we report quantitative profiles of eggs based on spectrometer reflectance for four major host species and the corresponding cuckoo gentes. The hosts include the oriental reed warbler (Acrocephalus orientalis), bull-headed shrike (Lanius bucephalus), azure-winged magpie (Cyanopica cyana), and black-faced bunting (Emberiza spodocephala). We show that (1) egg morphs of each host and corresponding cuckoo gens can be categorized by two chromatic components of reflectance spectra and (2) there is a significant difference in a particular chroma component between hosts and the cuckoo. We suggest that the cuckoo parasitism in central Japan originated from parasitism on the black-faced bunting. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 291-300., WILEY-BLACKWELL, Oct. 2009, BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, 98 (2), 291 - 300, web_of_science

    Scientific journal

  • Individual-based modeling of the spread of pine wilt disease: vector beetle dispersal and the Allee effect

    Fugo Takasu

    Pine wilt disease is caused by the pinewood nematode Bursaphelenchus xylophilus, which is vectored by the Japanese pine sawyer beetle Monochamus alternatus. Due to their mutualistic relationship, according to which the nematode weakens and makes trees available for beetle reproduction and the beetle in turn carries and transmits the nematode to healthy pine trees, this disease has resulted in severe damage to pine trees in Japan in recent decades. Previous studies have worked on modeling of population dynamics of the vector beetle and the pine tree to explore spatial expansion of the disease using an integro-difference equation with a dispersal kernel that describes beetle mobility over space. In this paper, I revisit these previous models but retaining individuality: by considering mechanistic interactions at the individual level it is shown that the Allee effect, an increasing per-capita growth rate as population abundance increases, can arise in the beetle dynamics because of the necessity for beetles to contact pine trees at least twice to reproduce successfully. The incubation period after which a tree contacted by a first beetle becomes ready for beetle oviposition by later beetles is crucial for the emergence of this Allee effect. It is also shown, however, that the strength of this Allee effect depends strongly on biological mechanistic properties, especially on beetle mobility. Realistic individual-based modeling highlights the importance of how spatial scales are dealt with in mathematical models. The link between mechanistic individual-based modeling and conventional analytical approaches is also discussed., SPRINGER TOKYO, Jul. 2009, POPULATION ECOLOGY, 51 (3), 399 - 409, doi;web_of_science

    Scientific journal

  • The importance of clutch characteristics and learning for antiparasite adaptations in hosts of avian brood parasites

    Bard G. Stokke; Fugo Takasu; Arne Moksnes; Eivin Roskaft

    There is considerable variation in rejection rates of parasitic eggs among hosts of avian brood parasites. In this article, we develop a model that can be used to predict host egg rejection behavior in brood parasite-host systems in general, by considering both intra- and interclutch variation in host egg appearance; clutch characteristics that may be important in calculating the fitness of individuals adopting rejecter or acceptor strategies. In addition, we consider the importance of learning the appearance of own eggs during the first breeding attempt and host probability of survival between breeding seasons on evolution of rejection behavior. Based on this model we can predict at which level of parasitism fitness of rejecter individuals is higher than that of acceptor individuals and vice versa. The model analyses show that variation in egg appearance can be a key factor for the evolution of host defense against parasitism. In more detail, analyses show that we should expect to find a prolonged learning period only in hosts that have a high intraclutch variation in egg appearance, because such hosts may potentially experience high costs in terms of recognition errors. Furthermore, learning is in general more adaptive in parasite-host systems in which hosts do have some reproductive success even when parasitized, and when parasitism rates are moderate. By including variables that have not been considered in previous models, our model represents a useful tool in investigations of host rejection behavior in various host-parasite systems., WILEY-BLACKWELL, Sep. 2007, EVOLUTION, 61 (9), 2212 - 2228, web_of_science

  • Nest light environment and the potential risk of common cuckoo (Cuculus canorus) parasitism

    A. Roman Munoz; Maria Altamirano; Fugo Takasu; Hiroshi Nakamura

    Brood parasitism represents a significant cost in reproduction; thus, natural selection should favor the evolution of host defenses, which in turn may favor evolution of more sophisticated techniques by the parasite to overcome host defenses. These host defenses include egg rejection, attacking parasites near the nest, and avoiding parasitism by concealing nest sites. In all these antiparasitism strategies, nest light environment may play an important role. In the present study, the risk of Common Cuckoo (Cuculus canorus) parasitism for the Great Reed Warbler (Acrocephalus arundinaceus) was modeled in relation to the in situ nest light environment, from far ultraviolet (UV) to infrared (IR) radiation (280-1,100 nm), and nest situation and structure. The percentage of photosynthetically active radiation (PAR) plus IR radiation (400-1,100 nm) falling on the nest, maximum nest width, and distance between the nest and the nearest active conspecific neighbor were significantly related to the risk of parasitism. Photosynthetically active radiation alone explained 65% of variation in parasitism risk in the final model. Although solar radiation levels in nests were low (<4%. for UV-B and UV-A radiation, 5% for PAR, and 22% for PAR plus IR radiation when cloudless), UV-B, UV-A, and visible-plus-IR radiation levels were significantly lower in nonparasitized nests. These findings provide the first evidence of a relationship between parasitism risk and nest concealment related to microhabitat light environment, with brighter nests suffering a higher risk of parasitism., AMER ORNITHOLOGISTS UNION, Apr. 2007, AUK, 124 (2), 619 - 627, web_of_science

    Scientific journal

  • Importance of spatial habitat structure on establishment of host defenses against brood parasitism

    Eivin Roskaft; Fugo Takasu; Arne Moksnes; Bard Gunnar Stokke

    We used metapopulation dynamics to develop a mathematical simulation model for brood parasites and their hosts in order to investigate the validity of the "spatial habitat structure hypothesis," which states that a low level of parasite egg rejection in host populations is due to the immigration of acceptor individuals from nonparasitized populations. In our model, we varied dispersal rate and the relative carrying capacity of host individuals in parasitized and unparasitized patches. When both the relative carrying capacity in the parasite-free patch and the dispersal rate increase, the nonparasitized patch will provide more acceptor individuals to the parasite-prone patch. As the relative carrying capacity in the parasite-free patch increases, the equilibrium frequency of rejecters both in the parasite-prone and in the parasite-free patch decreases toward zero for intermediate levels of the dispersal rate. Although the rejecter strategy is more adaptive than the acceptor strategy in the parasite-prone patch, large numbers of acceptors are produced in the parasite-free patch dispersing to the parasitized patch. As the number of individuals in the parasite-free patch increases, parasitism rate can be maintained stable at a high equilibrium level in the parasite-prone patch., OXFORD UNIV PRESS INC, Sep. 2006, BEHAVIORAL ECOLOGY, 17 (5), 700 - 708, doi;web_of_science

    Scientific journal

  • How does stochasticity in colonization accelerate the speed of invasion in a cellular automaton model?

    TAKASU Fugo; Kawasaki, K; F. Takasu; H. Caswell; N. Shigesada

    Mar. 2006, Ecological Research, 21, 334-354

  • A theoretical consideration on coevolutionary interactions between avian brood parasites and their hosts

    Fugo Takasu

    It has been suggested that parasitic interactions in general result in coevolutionary arms races where parasites and hosts evolve adaptive behaviours and traits to maximize their fitness in a conflicting manner. Avian brood parasitism provides an ideal system for the study of such coevolutionary interactions. In this paper I show and discuss possible consequences of the coevolutionary arms race inherent in avian brood parasitism, especially focusing on egg appearance, a key factor for the reproduction of both hosts and parasites. In such an arms race, hosts evolve the ability to recognize and hence to reject dissimilar parasitic eggs, while parasites counter host defences by more closely mimicking their eggs. Egg mimicry by parasites might then be de-stabilized by hosts changing the appearance of their eggs, thus exposing the mimics. The evolutionary trajectory of the arms race varies depending on the specific detailed mode of interaction between parasite and host individuals. Mathematical modeling, as an important parallel approach to empirical study, helps point the way for further study of avian brood parasitism so as to better understand coevolution in general. © 2005, The Ornithological Society of Japan. All rights reserved., 2005, Ornithological Science, 4 (1), 65 - 72, doi

    Scientific journal

  • How many eggs should be laid in one's own nest and others' in intra-specific brood parasitism?

    F Takasu

    Recent field studies have demonstrated that many bird species practice intra-specific brood parasitism. They lay eggs in the nests of other individuals of the same species, let the foster parents rear their offspring and avoid the cost of parental care. It has been shown that many birds, including starlings, swallows and geese, practice intra-specific brood parasitism in various forms. Intra-specific brood parasitism can be viewed in terms of optimal resource allocation: how many eggs should be put in the nests of other individuals under the risk of being parasitized by others. The situation here is a "game", because the fitness of a parasitic individual depends on how other individuals behave (how many individuals practice parasitism and to what extent). The ecology of intra-specific brood parasitism has been investigated extensively by field ornithologists recently and it is full of material for modeling population/evolutionary biology. In this paper, I present a simple individual-based model to challenge the resource allocation problem in intra-specific brood parasitism. Previous theoretical studies of intra-specific brood parasitism have been based on ESS or quantitative genetics models, where a population is implicitly assumed to be homogeneous and the distribution form of the trait being studied (the allocation rate or the number of eggs laid parasitically) is inherently monomorphic. This paper aims to explore the evolution of intra-specific brood parasitism without these restrictions. In the model, an individual is assigned a strategy, an allocation ratio of eggs that are laid parasitically in the nests of other individuals, and the strategy is inherited by offspring either asexually or sexually. Based on the simulation analysis, the evolution of the allocation rate (the extent of intra-specific brood parasitism) is discussed. The extension of this model to a tractable analytical model is also discussed., SPRINGER TOKYO, Dec. 2004, POPULATION ECOLOGY, 46 (3), 221 - 229, doi;web_of_science

    Scientific journal

  • Modelling the range expansion of pine wilt disease

    Yukie Mimura; Kohkichi Kawasaki; Fugo Takasu; Katsumi Togashi; Nanako Shigesada

    Pine wilt disease is caused by pinewood nematode (PWN), Bursaphelenchus xylophilus. The pine sawyer beetle, Monochamus alternatus, in a relationship of obligatory mutalism, vectors this nematode. For more than a century pine wilt disease has spread throughout much of Japan, and in recent times intense management efforts have been taken. These management strategies, however, have not been overly efficient. In this study, we have constructed a mathematical model to describe the spatial-temporal spread of pine wilt disease as a way to investigate the dependency of the range expansion speed (RES) of the disease on the eradication of the vector insect and the patch size of pine stands. We assume that beetles are eradicated at a rate theta only where the infected pine density is larger than a threshold, H-T and investigate how the range expansion speed changes with varying values of theta and H-T. Moreover, we change the patch size of pine stands, with the total area of pine stands being kept constant. The main results are as follows: i) as the eradication rate, theta, increases, the RES initially decreases gradually and then suddenly drops to zero at a certain value of theta; ii) it is impossible to eradicate the disease regardless of the value of theta, when the threshold of the infected pine density, H-T, exceeds a certain value; iii) as H-T decreases, the RES initially shows a gradual decrease and then suddenly drops to zero at a certain value of H-T; iv) it is impossible to eradicate pine wilt disease regardless of the value of H-T, when theta is below a certain value; and v) as the patch size of pine stands becomes larger, the RES increases., E J BRILL, 2004, Proceeding of the Fourth International Congress of Nematology, 2, 843 - 853, web_of_science

    International conference proceedings

  • Survival and anti-parasite defense in a host metapopulation under heavy brood parasitism: a source-sink dynamic model

    L Barabas; B Gilicze; F Takasu; C Moskat

    The obligate brood parasite common cuckoo Cuculus canorus, widespread in Eurasia, occasionally reaches a high parasitism rate (over 20%), which usually exists only for a short period of time and in cases of new parasitism. Recent results from Hungary proved that a remarkably high parasitism rate (50-66%) can also be maintained constantly for several decades. In this paradoxical situation the reproductive success of the strongly exploited host population is lower than would be necessary for self-reproduction. We developed a model for a hypothetical host-brood parasite system that demonstrated that immigration of naive individuals from a highly reproductive ("source") host population might explain the survival of the highly parasitized ("sink") population. Our results also showed the possibility of maintaining the high parasitism rate and the imperfection of the host's counter-adaptation against the brood parasite over a longer period. Gene flow was necessary to maintain both the acceptor genes and the non-mimetic cuckoo eggs in heavy parasitism. When the immigration rate was low (1-2%), an early expansion of the mimetic cuckoos was followed by a spread of anti-parasite defense, and consequently, the parasitism rate stabilized at a lower, but still relatively high level of about 45-60%., SPRINGER JAPAN KK, 2004, JOURNAL OF ETHOLOGY, 22 (2), 143 - 151, doi;web_of_science

    Scientific journal

  • How does spatio-temporal disturbance influence species diversity in a hierarchical competitive system? Prospective order of species coexistence and extinction

    K Ohsawa; K Kawasaki; F Takasu; N Shigesada

    To address how habitat destruction and hierarchical competition among species affect the spatio-temporal dynamics of a multi-species community, we present a compartment model in which multiple species undergo dispersal and competitive interactions in a patchy habitat arranged in a two-dimensional lattice. We assume that disturbances are periodically imposed on some parts of the lattice in a block, followed by a period free of disturbance. For convenience, species are ranked in order of competitive ability. We further assume that the intrinsic growth rate of species i, epsilon(i), and the dispersal ability, D-i, increase in decreasing order of rank. Our model can analytically determine the exact number of surviving species when disturbance is absent. In the presence of disturbance, we numerically examine how spatio-temporal changes in environmental heterogeneity affect species coexistence and extinction, for the case in which the value of epsilon(i)/D-i monotonically increases or decreases with rank. The results demonstrate that (1) when the interspecific competition is smaller than the intraspecific competition, we can provide predictions on the prospective order of species to be driven extinct and the order of potential species to revive with increasing extents of disturbance; (2) when the interspecific competition is stronger than intraspecific competition, a small difference in the disturbance level can lead to drastic changes in the species composition, their densities and the order of species extinction. In addition, comparison with other similar models reveals that differences in species interaction in local population dynamics critically affect the disturbance-mediated species diversity., SPRINGER-VERLAG TOKYO, Dec. 2003, POPULATION ECOLOGY, 45 (3), 239 - 247, doi;web_of_science

    Scientific journal

  • Co-evolutionary dynamics of egg appearance in avian brood parasitism

    F Takasu

    In avian brood parasitism, interactions between parasites and their hosts lead to a co-evolutionary process called an arms race. Field studies have shown that many host species have evolved an ability to recognize and reject parasite eggs that look unlike their own and that some parasites lay eggs of sophisticated mimicry. Egg appearance is a crucial factor that determines the reproductive success both of the parasites and their hosts in the arms race. The appearance of eggs, however, is a quantitative trait and the variation within a population could critically affect the dynamics of the arms race; parasite individuals that lay eggs more similar to those of the host are more likely to reproduce successfully, whereas host individuals that lay eggs more unlike those of the parasite have a better chance of rejecting parasitism and reproducing, which would de-stabilize the parasites' good mimicry. To explore the arms race for egg appearance, I constructed a model described by an integro-difference equation. The temporal change of the 'distributions' of egg appearance along a continuous spectrum was analysed both for the parasite and host populations. The model analyses show that (1) a conventional view of an arms race-'parasites chasing their hosts escaping from the parasites'-is realized in the early stage of the dynamics, but (2) the distributions of egg appearance finally converge to discrete point-distributions (polymorphism) even when any continuous distributions are used as the initial state. The latter might be relevant to the maintenance of polymorphism of egg appearance. Based on the model analysis, I discuss the implications of this model for general (co)evolutionary processes for quantitative traits and suggest a new modelling framework to account for such processes., EVOLUTIONARY ECOLOGY LTD, Mar. 2003, EVOLUTIONARY ECOLOGY RESEARCH, 5 (3), 345 - 362, web_of_science

    Scientific journal

  • Biological invasion into periodically fragmented environments: A diffusion-reaction model.

    N. Shigesada; N. Kinezaki; K. Kawasaki; F. Takasu

    (2003), 2003, In: Morphogenesis and Pattern Formation in Biological Systems: Experiments and Models (eds. T.Sekimura, S.Noji, N.Ueno & P.K.Maini). Springer-Verlag Tokyo., 215 - 222

  • Modeling biological invasions into periodically fragmented environments(共著)

    TAKASU Fugo

    2003, Theoretical Population Biology, 64, 291-302

  • Recurrent habitat disturbance and species diversity in a multiple-competitive species system

    K Ohsawa; K Kawasaki; F Takasu; N Shigesada

    To address how species interactions, dispersal and environmental disturbances interplay to affect the spatial distribution and diversity of species, we present a compartment model in which multiple species undergo competitive interaction of Lotka-Volterra type in a patchy environment arranged in a square lattice. Dispersal of species occurs between adjacent patches. Disturbances are periodically imposed on a central part of the environment in a belt-like block or an island-like block of various sizes where each species is killed for a certain time interval and then allowed to recover for the rest of a disturbance cycle. We deal with a case in which the local population dynamics within each patch is analytically determinable and has multiple locally stable equilibrium states in the absence of environmental disturbance. We further assume a trade-off between the reproductive rate of species and its dispersal ability. With these settings, we numerically examine how the spatio-temporal distributions of species are affected by changes in the pattern, size and duration of disturbances. The results demonstrate that: (1) in the undisturbed area, environmental disturbances could generate spatially segregated distributions of species; (2) in the disturbed area, species with higher dispersal abilities quickly invade and preferentially recover their population during the post-disturbance period, being temporarily relieved of competition from other species. These mechanisms collectively lead to increased species diversity in the whole habitat, functioning best when both the size and duration of disturbances are intermediate. In particular, the belt-like disturbance is more effective than the island-like disturbance in sustaining spatial heterogeneity for a wider range of duration of disturbance. (C) 2002 Elsevier Science Ltd. All rights reserved., ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, May 2002, JOURNAL OF THEORETICAL BIOLOGY, 216 (2), 123 - 138, doi;web_of_science

    Scientific journal

  • Modeling spawning strategy for sex change under social control in haremic angelfishes

    Y Hamaguchi; Y Sakai; F Takasu; N Shigesada

    In haremic angelfishes where protogynous (female to male) sex change is favored, females have been reported to adopt several tactics for earlier sex change on the basis of a trade-off between reproduction and growth, or survivorship. A recent field study on Centropyge ferrugatus revealed that females reduce spawning frequency in competition with similar-sized neighbors for social dominance. To evaluate the optimal spawning strategy taken by haremic fishes, we developed an evolutionarily stable strategy model that focuses on their life history and social structure based on field data of C. ferrugatus. The results of the analysis predict that the spawning frequency will be low when the mortality rate of females is high compared with males, the harem size is large, and there is a moderate degree of social control. Our model further predicts conditions under which females completely stop spawning, as if they have become bachelors. Thus, the regulated spawning frequency may be taken as a strategy to optimize the reproductive success of an individual in response to the available choices for sex change, social control, and environmental conditions. Social control would also play an important role in sex change in many other haremic species., OXFORD UNIV PRESS INC, Jan. 2002, BEHAVIORAL ECOLOGY, 13 (1), 75 - 82, web_of_science

    Scientific journal

  • Diffusive waves, dynamical stabilization and spatio-temporal chaos in a community of three competitive species

    S Petrovskii; K Kawasaki; F Takasu; N Shigesada

    The spatio-temporal dynamics of three competitive species is considered. Mathematically, the community is described by a system of partial differential equations of Lotka-Volterra type. The properties of the system are investigated both numerically and analytically. We show that for finite initial conditions the dynamics of the system is typically reduced to a succession of travelling diffusive waves, some of which demonstrate rather an unusual behaviour. Particularly, a locally unstable equilibrium can become stable in the wake of a diffusive front. After propagation of the waves, the domain is invaded by irregular spatiotemporal population oscillations that can be classified as spatio-temporal chaos., KINOKUNIYA CO LTD, Jun. 2001, JAPAN JOURNAL OF INDUSTRIAL AND APPLIED MATHEMATICS, 18 (2), 459 - 481, web_of_science

    Scientific journal

  • Spatial spread of pine wilt disease : modeling the dispersal distance distribution of the pine sawyer beetle, Monochamus alfernatus(共著)

    Nunotani H; K. Kawasaki; F. Takasu; K. Togashi; N. Shigesada

    2001, Protection of World Forests from Insect Pests: Advances in Research (eds. H. Evans & A. Liebhold) IUFRO World Series, 11, 79-85

  • Morphological plasticity in the coral Porites sillimaniani and its adaptive significance

    S Muko; K Kawasaki; K Sakai; F Takasu; N Shigesada

    The whole-colony morphology of the coral, Porites sillimaniani, varies dramatically in accordance with light intensity from plate-like shape to branching shape. To determine whether the variation is based on genetic difference or phenotypic plasticity, we conducted a field experiment by transplanting coral fragments taken from seven plate-like colonies to different light conditions. The fragments that transplanted to the high-light condition started to have branches in 8 mo period of the experiment, whereas those to the low-light condition remained to be flat. This result suggests that the morphological variation is the phenotypic plasticity in response to light availability. To examine the adaptive significance of this plasticity a simple mathematical model of coral shape is constructed in which the number of branches, their angles and lengths are morphological parameters. The circumference of the model coral is assumed to be uniformly covered with polyps. Each polyp survives if its light flux is larger than a certain threshold value. The optimal morphology that can support a maximum number of viable polyps is calculated for a given light intensity. The optimal coral shape changes with light intensity, which agrees qualitatively with the observation of P. sillimaniani colony in natural habitats., ROSENSTIEL SCH MAR ATMOS SCI, Jan. 2000, BULLETIN OF MARINE SCIENCE, 66 (1), 225 - 239, web_of_science

    Scientific journal

  • Modeling the expansion of an introduced tree disease

    Fugo Takasu; Namiko Yamamoto; Kohkichi Kawasaki; Katsumi Togashi; Yoichi Kishi; Nanako Shigesada

    Pine wilt disease is caused by the introduced pinewood nematode, Bursaphelenchus xylophilus, for which the vector is the pine sawyer beetle, Monochamus alternatus. Native Japanese pines, black pine “Pinus thunbergii” and red pine “P. densiflora”, are extremely sensitive to the nematode's infection, and the parasite has been expanding nationwide in the last few decades, despite intensive control efforts. To understand the parasite's range expansion in Japan, we modeled the dynamics of the pines and the beetle that disperses the nematode, using an integro-difference equation in a one-dimensional space. Based on field data collected in Japan, we investigated the dependence of the parasite's rate of range expansion on the eradication rate of the beetle, the initial pine density, and the beetle dispersal ability. Our model predicts several results. “1” The Allee Effect operates on beetle reproduction, and consequently the parasite cannot invade a pine stand, once the beetle density decreases below a threshold. “2” The distribution of the dispersal distance of the beetles critically affects the expansion rate of the disease. As the fraction of the beetles that travel over long distance increases from zero, the range expansion accelerates sharply. “3” However, too frequent long-range dispersal results in a failure of the parasite invasion due to the Allee Effect, suggesting the importance of correctly assessing the beetle's mobility to predict the speed of range expansion of the parasite. “4” As the eradication rate is increased, the range expansion speed decreases gradually at first and suddenly drops to zero at a specific value of the eradication rate., 2000, Biological Invasions, 2 (2), 141 - 150, doi

    Scientific journal

  • マツ枯れシステムのダイナミクスと大域的伝播の数理解析(共著)

    YAMAMOT Namiko; TAKASU Fugo; KAWASAKI Kohkichi; TOGASHI Katsumi; KISHI Youichi; SHIGESADA Nanako

    2000, 日本生態学会誌 50, 50, 269-276

  • Modeling the spread of pine wilt disease caused by nematodes with pine sawyers as vector

    A Yoshimura; K Kawasaki; F Takasu; K Togashi; K Futai; N Shigesada

    An epidemic of pine wilt disease has been spreading in wide areas of Japan for nearly a century. The disease is caused by the pinewood nematode, Bursaphelenchus xylophilus, with the pine sawyer, Monochamus alternatus, as vector. The spread of disease is facilitated by an obligatory mutualism between the nematode and the pine sawyer: the pine sawyer helps the nematode transmit to a new host tree, while the nematode supplies the pine sawyer with newly killed trees on which to lay eggs. We present a mathematical model to describe the host-vector interaction between pines and pine sawyers carrying nematodes, on the basis of detailed data on the population dynamics of pine sawyers and the incidence of pine wilt disease at a study site located on the northwest coast of Japan. We used the model to simulate the dynamics of the disease and predict how the epidemic could be controlled by eradication of the pine sawyer, The main results are as follows: (1) There is a minimum pine density below which the disease always fails in invasion. However, even if the pine density exceeds this minimum, the disease fails in invasion due to the Allee effect when the density of pine sawyers is very low. (2) The: minimum pine density increases disproportionately with increase in the eradication rate. (3) The probability that a healthy tree will escape from infection until the epidemic dies out decreases sharply with increase in the initial pine density or the initial density of pine sawyers., ECOLOGICAL SOC AMER, Jul. 1999, ECOLOGY, 80 (5), 1691 - 1702, web_of_science

    Scientific journal

  • Mathematical models for biological invasions-competition for open spaces(共著)

    Takasu F; M. Shiraishi; K. Kawasaki; N. Shigesada

    1999, Biological Invasions of Ecosystem by Pests and Beneficial organisms, NIAES Series 3, 78-87

  • Population dynamics of nitrifying bacteria in an aquatic ecosystem(共著)

    Kubo Y; F. Takasu; R. Shimura; S. Nagaoka; N. Shigesada

    1999, Biological Sciences in Space, 13 (4), 333-340

  • Modelling the arms race in avian brood parasitism

    F Takasu

    In brood parasitism, interactions between a parasite and its host lead to a co-evolutionary process called an arms race, in which evolutionary progress on one side provokes a further response on the other side. The host evolves defensive means to reduce the impact of parasitism, while the parasite evolves means to counter the host's defence. To gain insights into the co-evolutionary process of the arms race, a model is developed and analysed, in which the host's defence and the parasite's counterdefence are assumed to be genetically determined. First, the effect of parasite counterdefence on host defence is analysed. I show that parasite counterdefence can critically affect the establishment of host defence, giving rise to three situations in the equilibrium state: The host shows (1) no defence, (2) an intermediate level of defence or (3) perfect defence. Based on these results, the evolution of parasite counterdefence is considered in connection with host defence. It is suggested that the parasite can evolve counterdefence to a certain degree, but once it has established counterdefence beyond this, the host gives up its defence against parasitism provided the defence entails some cost to perform. Dynamic aspects of selection pressure are crucial for these results. Based on these results, I propose a hypothetical evolutionary sequence in the arms race, along which interactions between the host and parasite proceed., KLUWER ACADEMIC PUBL, Nov. 1998, EVOLUTIONARY ECOLOGY, 12 (8), 969 - 987, web_of_science

    Scientific journal

  • Why do all host species not show defense against avian brood parasitism: Evolutionary lag or equilibrium?

    F Takasu

    Avian brood parasitism reduces the reproductive success of hosts and is therefore expected to select for host defenses against parasitism, such as an ability to reject parasitic eggs. Field studies have shown that some hosts recognize and reject parasitism, whereas others do not, and the degree of the defense varies from population to population. One long-standing debate concentrates on the differences in the distribution of host defenses observed in hosts parasitized by the brown-headed cowbird and the common cuckoo. The cowbird's hosts show either few or nearly perfect defenses, whereas the cuckoo's hosts have defenses varying from none to complete, with most falling in between the two extremes. To explore the mechanisms underlying this pattern, I constructed a mathematical model in which host defense is assumed to be genetically determined and analyzed how the host defense is established under parasitic pressure. The model shows that differences in the defense-level distribution can be attributed to the difference in the parasite's breeding strategy, generalized or specialized: hosts parasitized by generalists show perfect, none, or intermediate levels of the defense depending on the host abundances, whereas hosts parasitized by specialists always exhibit either none or intermediate levels of the defense if the parasite lacks counterdefenses such as egg mimicry. This result provides a testable explanation for the existence of accepter species of the brown-headed cowbird, which might reconcile the previously conflicting hypotheses., UNIV CHICAGO PRESS, Feb. 1998, AMERICAN NATURALIST, 151 (2), 193 - 205, web_of_science

    Scientific journal

  • Simulation study of Stratitied Diffusion Model(共著)

    TAKASU Fugo; KAWASAKI Kohkichi; SHIGESADA Nanako

    1997, Forma, 12, 167-175

  • 行動と共進化-托卵鳥とその宿主

    TAKASU Fugo

    1995, 日本生態学会誌, 45 (2), 191-197

  • MODELING THE POPULATION-DYNAMICS OF A CUCKOO-HOST ASSOCIATION AND THE EVOLUTION OF HOST DEFENSES

    F TAKASU; K KAWASAKI; H NAKAMURA; JE COHEN; N SHIGESADA

    Cuckoo parasitism in Nagano Prefecture in Japan has shown dramatic changes in the parasitism rate, host usage by the cuckoo, and defensive behavior of hosts during the past 60 yr. To gain insights into these phenomena, we model the population dynamics of a cuckoo-host association together with the population genetics of a rejecter gene in the host population. Analysis shows that both the dynamical change in the host-parasite association and the establishment of the host's counteradaptation crucially depend on the product of two factors, the carrying capacity of the host and cuckoo's searching efficiency. When the product is less than a critical value, the host population cannot evolve a counteradaptation even if parasitized by the cuckoo. Hence, the lack of counteradaptation does not necessarily imply that the host population only recently has become parasitized. As the product becomes larger, the rejection behavior will be eventually established at higher levels in the host population. In this case, the spreading of rejection behavior is very fast, which suggests that the cuckoo-host association reaches an equilibrium state within a relatively short period. These results make possible new interpretations of several circumstances reported about cuckoo-host associations., UNIV CHICAGO PRESS, Nov. 1993, AMERICAN NATURALIST, 142 (5), 819 - 839, web_of_science

    Scientific journal

MISC

  • フィールド研究と数理モデル研究

    TAKASU Fugo

    Jan. 2003, 生物科学, 54 (2), 111-118

  • The role of theoretical models explaining the relationships between brood parasites and their hosts

    TAKASU Fugo

    1999, Proceedings of 22nd International Ormthological Congress Adams, N-J. & Slotow, R. H. (eds.), 3146-3164

Books etc

  • Chapter "Evolution and Maintenance of Egg Rejection by Hosts as Adaptation Against Conspecific Brood Parasites: An Individual-Based Model" in Avian Brood Parasitism, Behaviour, Ecology, Evolution and Coevolution

    TAKASU Fugo (, Range: 分担)

    Springer International Publishing, Apr. 2018

  • 招かれない虫たちの話 虫がもたらす健康被害と害虫管理, 第11章「感染症流行の数理的研究」執筆

    TAKASU Fugo (, Range: 分担)

    東海大学出版部, Mar. 2017 (ISBN: 9784486021254)

  • 行動生物学辞典

    TAKASU Fugo (, Range: 分担)

    東京化学同人, Nov. 2013

  • シリーズ現代の生態学・第5巻・行動生態学 第5章執筆

    TAKASU Fugo (, Range: 分担)

    共立出版, Jun. 2012, 98- 119 (ISBN: 9784320057388)

  • 数理科学事典

    TAKASU Fugo (, Range: 筆頭著者)

    丸善, Nov. 2009, 278-281

  • 個体性を保ったダイナミクスモデル シリーズ 数理生物学要論 巻2「空間」の数理生物学 第6章

    TAKASU Fugo (, Range: 筆頭著者)

    共立出版, May 2009, 第6章

  • オナガの分布域拡大に伴うカッコウとの新たな関係、「鳥の自然史」第6章

    TAKASU Fugo (, Range: 分担)

    北海道大学出版会, 2009, 第6章

  • Phenotypic Evolution

    TAKASU Fugo (, Range: 分担)

    メディカル・サイエンス・インターナショナ, 2009, 第20章

  • 持続不可能性 - 環境保全のための複雑系理論入門(共訳)\nFragile Dominion by Simon Levin (1999) Perseus Publishing, Cambridge, Massachusetts

    TAKASU Fugo

    持続不可能性 - 環境保全のための複雑系理論入門 文一総合出版, Oct. 2003, 1-376頁

  • リンデンマイヤー・システムとしての植物根系の形態(共著)

    TAKASU Fugo

    生物の形の多様性と進化 - 遺伝子から生態系まで -\n関村利朗・野地澄晴・森田利仁 共編 裳華房 第14章, Jun. 2003, 152-162頁

  • 数理生態学と鳥類学-托卵を題材にして- 第8章執筆(191-222)

    TAKASU Fugo

    これからの鳥類学\n山岸哲・樋口広芳 共編 裳華房, 2002, 第8章(191-222項)

  • 新人口論-生態学的アプローチ\nHow many people can the earth support? Joel. E. Cohen\n共訳

    TAKASU Fugo

    新人口論-生態学的アプローチ\n農山漁村文化協会, 656 pages, 1998

Presentations

  • Spatial metapopulation dynamics as a point pattern dynamics

    TAKASU Fugo

    日本数理生物学会2019年大会, 16 Sep. 2019

  • Equilibrium properties of the spatial SIS model as a point pattern dynamics

    TAKASU Fugo; Fugo TAKASU

    Seminar at the department of mathematics, Dhaka University, Bangladesh, Feb. 2019

  • Equilibrium properties of the spatial SIS model as a point pattern dynamics

    TAKASU Fugo; Fugo TAKASU

    Mathematical modeling workshop at EnFRA, Dec. 2018, EnFRA in Busan, Korea

  • An approach to study adaptive community dynamics

    TAKASU Fugo; Fugo TAKASU

    Mini-workshop on the new development of aquatic ecosystem model, Dec. 2018, Hanyang University ERICA, Korea

  • Equilibrium properties of the spatial SIS model as a point pattern dynamics

    TAKASU Fugo; Fugo TAKASU

    Seminar at the department of biology, Kyung Hee University, Korea, Dec. 2018, Kyung Hee University, Seoul, Korea

  • Equilibrium properties of the spatial SIS model as a point pattern dynamics

    TAKASU Fugo; Fugo TAKASU

    Seminar at the department of physics, Inha University, Korea, Dec. 2018, Inha University, Incheon, Korea

  • Spatial metapopulation dynamics as a point pattern dynamics

    TAKASU Fugo; Fugo TAKASU

    The 8th EAFES (East Asian Federation of Ecological Societies) International Congress, Apr. 2018, East Asian Federation of Ecological Societies, Nagoya University, Nagoya, Japan

  • Spatial metapopulation dynamics as a point pattern dynamics

    TAKASU Fugo

    日本生態学会第65回大会, Mar. 2018, 日本生態学会, 札幌コンベンションセンター、札幌市

  • Spatial population dynamics of biological phenomena

    TAKASU Fugo; Fugo Takasu

    Seminar at the School of Mathematics and Statistics of Wuhan University, Dec. 2017, School of Mathematics and Statistics of Wuhan University, Wuhan, China

  • Mathematical and Computational Approaches to Spatial Modeling in Ecology

    TAKASU Fugo; Fugo Takasu

    Seminar at the School of Mathematical Sciences of Soochow University, Dec. 2017, School of Mathematical Sciences of Soochow University, Suzhou, China

  • Mathematical and computational approaches to spatial modelling in ecology

    TAKASU Fugo; Fugo Takasu

    ISEM 2017 Global Conference Pre-conference short course, Sep. 2017, Society of Ecological Modeling, Jeju island, Korea

  • Modeling the spatial spread spread of the pine wilt disease - how does vector beetle dispersal affect disease expansion?

    TAKASU Fugo; Fugo Takasu

    ISEM 2017 Global Conference, Jeju, Korea, Sep. 2017, Society of Ecological Modeling, Jeju island, Korea

  • Meta-population dynamics as a stochastic point pattern

    TAKASU Fugo; Fugo Takasu

    Seminar at National Institute of Ecology of Korea, Sep. 2017, National Institute of Ecology of Korea, Gunsan, Korea

  • Point pattern dynamics - a challenge to work on spatial population dynamics

    TAKASU Fugo; Fugo Takasu

    VNU NUS Miniworkshop "Selected topics in mathematical modeling", Nov. 2016, VNU University of Science, Hanoi, Vietnam

  • Spatial population dynamics as a point pattern dynamics

    TAKASU Fugo; Fugo Takasu

    Symposium - What is a good model? Evidential statistics, information criterion and model evaluation, Jan. 2016, 統計数理研究所

  • Hidden Markov Model as a tool to study animal behaviors

    TAKASU Fugo; Fugo Takasu

    Seminar at the Institute of Forestry and Environmental Science, Chittagong University, Bangladesh, Nov. 2015, Chittagong University, Bangladesh

  • Spatial population dynamics as a point pattern dynamics

    TAKASU Fugo

    東京大学大学院数理科学研究科・数理生物学セミナー, Nov. 2015, 東京大学駒場キャンパス

  • Spatial epidemic models as a point pattern dynamics

    TAKASU Fugo; Fugo Takasu

    Symposium "Advances in spatial ecology", JSMB CJK 20015, Doshisha University 26- 29 August 2015., Aug. 2015, Japan Society for Mathematical Biology, Joint meeting with China, Japan, and Korea 2015, 同志社大学今出川キャンパス

  • Modeling the spatial spread of the pine wilt disease - an individual-based approach

    TAKASU Fugo; Fugo Takasu

    Seminar talk at the Chinese Academy of Forestry, Beijing, Jan. 2015, Beijing, China

  • Modeling the maintenance of egg polymorphism over geographic scale

    TAKASU Fugo; Fugo Takasu

    Seminar talk at the Institute of Zoology, Chinese Academy of Sciences, Beijing, Jan. 2015, Beijing, China

  • Modeling the spatial spread of the pine wilt disease - an individual-based approach

    TAKASU Fugo; Fugo Takasu

    Seminar at Kyung Hee University, Seoul, Korea, Dec. 2014, Seoul, Korea

  • Modeling spatial spread of infectious disease - an individual-based approach

    TAKASU Fugo; Fugo Takasu

    Seminar at the Institute of Forestry and Environmental Science of the University of Chittagong, Chittagong, Bangladesh, Nov. 2014, Chittagong, Bangladesh

  • Modeling the spatial spread of the pine wilt disease - an individual-based approach

    TAKASU Fugo; Fugo Takasu

    Seminar at Busan National University, Busan, Korea, Nov. 2014, Busan, Korea

  • Modeling the spatial spread of the pine wilt disease - an individual-based approach

    TAKASU Fugo; Fugo Takasu

    IUFRO 2014, International Union of Forest Research Organizations, Oct. 2014, Salt Lake City, Utah, USA

  • A spatial modeling of egg mimicry in avian brood parasitism

    TAKASU Fugo; Fugo Takasu

    The Joint annual meeting of the Japanese society for mathematical biology and the society for mathematical biology, Aug. 2014, Japanese society for mathematical biology and the society for mathematical biology, 大阪グランキューブ

  • Modeling the maintenance of egg polymorphism over geographic scale

    TAKASU Fugo; Fugo Takasu

    The 26th International Ornithological Congress, Aug. 2014, Rikkyo University, Tokyo

  • Modeling spatial dynamics of egg polymorphism in a cuckoo-host interactions

    TAKASU Fugo; Fugo Takasu

    Seminar talk at Jeju National University, Jeju, Korea, Jun. 2014, Jeju, Korea

  • 1) Spatial population dynamics of "games for territory", 2) Modeling spatial spread of infectious disease - an individual-based approach, 3) Modeling spatial dynamics of egg polymorphism in a cuckoo-host interactions

    TAKASU Fugo; Fugo Takasu

    Seminar talks at Busan National University, Busan, Korea, Jun. 2014, Busan, Korea

  • Individual-based modeling of the spread of the pine wilt disease

    TAKASU Fugo; Fugo Takasu

    College of Life Sciences, Hainan Normal University, China, Dec. 2013

  • 1) A spatial territory game in continuous space\n2) Individual-based modeling of the spread of pine wilt disease

    TAKASU Fugo; Fugo Takasu

    Institute of Forestry and Environmental Sciences, University of Chittagong, Bangladesh, May 2013, Chittagong

  • 連続空間上の個体ベース個体群動態

    TAKASU Fugo

    日本生態学会第60回全国大会\n企画集会T05「個体の視点から構成する空間個体群動態」, Mar. 2013, 日本生態学会, 静岡県コンベンションセンター(グランシップ)

  • Modeling maintenance of egg polymorphism over a geographical scale

    TAKASU Fugo; Fugo Takasu

    International Symposium on Avian Brood Parasitism in Honour of Significant Brood Parasitism Scientists, Nov. 2012, Hainan Normal University, Norwegian University of Science and Technology, and China Ornithological Society, Haikou, Hainan province, China

  • 日本のライチョウ集団のの絶滅可能性解析

    TAKASU Fugo

    第13回ライチョウ会議岐阜大会, Oct. 2012, 高山市役所ホール

  • An individual-based stochastic population dynamics of the Rock Ptarmigan in Japan

    TAKASU Fugo; Fugo Takasu; Ayaka Suzuki; nAtsushi Kobayashi; Hiroshi Nakamura

    The 12th International Grouse Symposium, Jul. 2012, Matsumoto, Nagano, Japan

  • Individual-based models of spatial population/evolutionary dynamics

    TAKASU Fugo; Fugo Takasu

    China-Japan-Korea International Conference of Mathematical Biology, May 2012, Korean Society of Mathematical Biology, Busan, Korea

  • 鳥類育児寄生における卵色多型の集団遺伝モデル

    TAKASU Fugo

    日本鳥学会員近畿地区懇談会第103回例会, Dec. 2011, 奈良女子大学

  • 個体の視点から組み立てる個体群動態モデル

    TAKASU Fugo

    個体群生態学会 第27回大会(岡山大学 10月14- 16日) 企画シンポジウム「個体ベースで考える集団の争い」, Oct. 2011, 岡山大学

  • 連続空間上の個体ベース個体群動態とその数理的取り扱いについて

    TAKASU Fugo

    第21回日本数理生物学会(明治大学 9月13- 15日)企画シンポジウム「空間的制約下におけるダイナミクス」, Sep. 2011, 明治大学

Teaching Experience

  • Science Open Laboratory II E (Nara Women's University)

  • Science Open Laboratory I E (Nara Women's University)

  • Academic Guidance Understand Biology using Matheamtics (Nara Women's University)

  • Passage 24A (Nara Women's University)

  • Population dynamics (Nara Women's University)

Association Memberships

  • Ecological Society of Japan

  • Japan Society of Mathematical Biology

  • Ornithological Society of Japan

Works

  • Evolutionary games in continuous space

    2008

  • Evolutionary games in continuous space

    2008

  • Evolution of competition

    Mar. 2005, Dec. - 2005

  • Evolution of competition

    Mar. 2005, Dec. - 2005

  • Brood parasitism in arctic area

    Nov. 2005

  • Brood parasitism in arctic area

    Nov. 2005

  • Avian brood parasitism

    Sep. 2005

  • Avian brood parasitism

    Sep. 2005

  • Coevolution of avian brood parasites and their hosts

    Jun. 2003, May - 2005

  • Coevolution of avian brood parasites and their hosts

    Jun. 2003, May - 2005

  • Evolution of host defense in avian brood parasitism

    Jan. 2002

  • Evolution of host defense in avian brood parasitism

    Jan. 2002



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