## TAKAHASHI SatoshiFaculty Division of Natural Sciences Research Group of Environmental Sciences Professor Contact： takahasilisboa.ics.nara-wu.ac.jp |

Last Updated :2021/06/02

- 2007, -:奈良女子大学大学院人間文化研究科准教授
- 2000, -:奈良女子大学大学院人間文化研究科助教授
- 1997, -:大阪大学大学院理学研究科講師
- 1994, -:大阪大学理学部講師
- 1994, -:大阪大学教養部講師
- 1990, -:大阪市立大学理学部助手

- - 1990, Kyoto University, 理学研究科, 生物物理学専攻, Japan
- - 1990, Kyoto University, Graduate School, Division of Natural Science

- Zoological Science Award, Michio Hori;Mifuyu Nakajima;Hiroki Hata;Masaki Yasugi;Satoshi Takahashi;Masanori Nakae;Kosaku Yamaoka;Masanori Kohda;Jyun-ichi Kitamura;Masayoshi Maehata;Hirokazu Tanaka;Norihiro Okada;Yuichi Takeuchi, Laterality is Universal Among Fishes but Increasingly Cryptic Among Derived Groups, 日本動物学会, Jun. 2018

Measuring and evaluating morphological asymmetry in fish: Distinct lateral dimorphism in the jaws of scale-eating cichlids

The left-right asymmetry of scale-eating Tanganyikan cichlids is described as a unilateral topographical shift of the quadratomandibular joints. This morphological laterality has a genetic basis and has therefore been used as a model for studying negative frequency-dependent selection and the resulting oscillation in frequencies of two genotypes, lefty and righty, in a population. This study aims were to confirm this laterality in Perissodus microlepis Boulenger and P. straeleni (Poll) and evaluate an appropriate method for measuring and testing the asymmetry. Left-right differences in the height of the mandible posterior ends (HMPE) and the angle between the neurocranium and vertebrae of P. microlepis and P. straeleni were measured on skeletal specimens. Snout-bending angle was also measured using a dorsal image of the same individuals following a previous method. To define which distribution model, fluctuating asymmetry (FA), directional asymmetry (DA), or antisymmetry (AS), best fit to the lateral asymmetry of the traits, we provided an R package, IASD. As a result, HMPE and neurocranium-vertebrae angle of both species were best fitted to AS, suggesting that P. microlepis and P. straeleni showed a distinct dimorphism in these traits, although snout-bending angle of P. microlepis was best fitted to FA. Measurement error was low for HMPE comparing the snout-bending angle in P. microlepis, indicating that measuring HMPE is a more accurate method. The scale-eating tribe Perissodini showed distinct antisymmetry in the jaw skeleton and neurocranium-vertebrae angle, and this laterality remains a valid marker for further evolutionary studies. © 2013 The Authors., Nov. 2013, Ecology and Evolution, 3 (14), 4641 - 4647, doiScientific journal

Evolution of dwarf males and a variety of sexual modes in barnacles: an ESS approach

Questions: Why do barnacles have many modes of sexuality, including hermaphroditism, androdioecy (large hermaphrodites with dwarf males), and dioecy (large females with dwarf males)? Can mating group size, relative body size, competitive advantage or survival rate of dwarf male individuals explain which type of sexuality is favoured by natural selection? Mathematical methods: We developed an ESS model to investigate factors affecting the optimal proportion of larvae that become dwarf males (q*). Allocation to male function of large hermaphrodites is calculated according to Charnov's sex allocation theory, although sperm competition with dwarf males is taken into account. Our model is based on a life history of androdioecious barnacles, which includes hermaphroditism (q* = 0) and dioecy (q* > 0 and the male allocation of large hermaphrodites = 0) as special cases. We incorporate average mating group size (m) into the model, together with body size, competitive advantage, and survival rate of dwarf males relative to large hermaphrodites. Results: The proportion of dwarf males, q*, increases from 0 (hermaphroditism) as mating group size decreases, and approaches 0.5 when group size, m, nears 0. At the latter extreme, large individuals should become females instead of hermaphrodites. Thus mating group size can explain the major trend of sexuality in barnacles: hermaphroditism in relatively large mating groups, androdioecy in smaller groups, and dioecy in even smaller groups. Relative body size, competitive advantage, and survival rate of dwarf males all have positive effects on the evolutionarily stable proportion of males. If there is a simple trade-off between body size and survival rate, survival rate will have the greater influence on sexuality., EVOLUTIONARY ECOLOGY LTD, Jul. 2009, Evolutionary Ecology Research, 11 (5), 713 - 729, web_of_scienceScientific journal

Mating group size and evolutionarily stable pattern of sexuality in barnacles

Barnacles, marine crustaceans, have various patterns of sexuality depending on species including simultaneous hermaphroditism, androdioecy (hermaphrodites and dwarf males), and dioecy (females and dwarf males). We develop a model that predicts the pattern of sexuality in barnacles by two key environmental factors: (i) food availability and (ii) the fraction of larvae that settle on the sea floor. Populations in the model consist of small individuals and large ones. We calculate the optimal resource allocation toward male function, female function and growth for small and large barnacles that maximizes each barnacle's lifetime reproductive success using dynamic programming. The pattern of sexuality is defined by the combination of the optimal resource allocations. In our model, the mating group size is a dependent variable and we found that sexuality pattern changes with the food availability through the mating group size: simultaneous hermaphroditism appears in food-rich environments, where the mating group size is large, protandric simultaneous hermaphroditism appears in intermediate food environments, where the mating group size also takes intermediate value, the other sexuality patterns, androdioecy, dioecy, and sex change are observed in food-poor environments, where the mating group size is small. Our model is the first one where small males can control their growth to large individuals, and hence has ability to explain a rich spectrum of sexual patterns found in barnacles. © 2008 Elsevier Ltd. All rights reserved., ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 07 Jul. 2008, Journal of Theoretical Biology, 253 (1), 61 - 73, doi;web_of_science;pubmedScientific journal

Do tiny males grow up? Sperm competition and optimal resource allocation schedule of dwarf males of barnacles

Barnacles, marine crustaceans, have three sexual patterns: simultaneous hermaphroditism, dioecy and androdioecy. In dioecy and androdioecy, large individuals (females and hermaphrodites, respectively) are attached by dwarf males. Depending on species, some dwarf males grow up, others do not in their life time. To investigate which environmental conditions affect growth patterns of dwarf males of barnacles, we investigate the evolutionarily stable life history strategy of dwarf males using Pontryagin's maximum principle. Sperm competition among dwarf males and that among dwarf males and large hermaphrodites is taken into account. Dwarf males grow up in food-rich environments, while they do not grow at all in food-poor environments. ESS of the resource allocation schedule between reproduction and growth follows an "intermediate growth strategy" (simultaneous growth and reproduction) for dioecious species, in which sperm competition is not severe. On the other hand, it approaches "bang-bang control" (switching from allocating all resources toward growth then to reproduction), as sperm competition against surrounding large hermaphrodites becomes severe in androdioecious species. © 2006 Elsevier Ltd. All rights reserved., ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 21 Mar. 2007, Journal of Theoretical Biology, 245 (2), 319 - 328, doi;web_of_science;pubmedScientific journal

Effects of dormant duration, body size, self-burial and water condition on the long-term survival of the apple snail, Pomacea canaliculata (Gastropoda : Ampullariidae)

We investigated factors influencing the survival of the apple snail, Poinacea canalicidata during dormancy in the laboratory at 20-26 degrees C. We placed snails of three size classes in small pots with soil and water, drained the water to induce self-burial, and subsequently checked the snails' survival at intervals. The duration of the dormant period, body size and the success of self-burial all affected the survival of the snails. The effects of water conditions (dry or moist) affected the survival of the snails through interactions with body size and duration. The longest duration of survival under dry conditions was 11 months, and a small proportion of medium-sized and large snails survived the entire experimental period of 29 months under moist conditions., JAPAN SOC APPL ENTOMOL ZOOL, Nov. 2006, APPLIED ENTOMOLOGY AND ZOOLOGY, 41 (4), 627 - 632, doi;web_of_scienceScientific journal

Coexistence of competing species by the oscillation of polymorphisms

Scale-eating cichlids in Lake Tanganyika exhibit genetically determined lateral asymmetry, especially in their mouth-opening. Frequencies of the morphs oscillate due to strong frequency-dependent selection caused by the switching of prey's attention, and its delayed effect by their growth period. Two scale-eaters coexist in similar densities at south shore of the lake, with their morph frequencies oscillating in phase. We investigated the effect of the oscillation in morph frequencies to the coexistence of competing species. If the difference of two species' growth period is large, the oscillation facilitates the coexistence of the two species, while small difference of growth periods hinders their coexistence. In the latter case, the species with shorter growth period drives the other species to the extinction. (c) 2005 Elsevier Ltd. All rights reserved., ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD, Aug. 2005, JOURNAL OF THEORETICAL BIOLOGY, 235 (4), 591 - 596, doi;web_of_scienceScientific journal

Dimension spectra of self-affine sets

The dimension spectrum H(delta) is a function characterizing the distribution of dimension of sections. Using the multifractal formula for sofic measures, we show that the dimension spectra of irreducible self-affine sets (McMullen's Carpet) coincide with the modified Legendre transform of the free energy Psi(d)(beta). This variational relation leads to the formula of Hausdorff dimension of self-affine sets, max(delta+H(delta)) = Psi(d) (eta), where 71 is the logarithmic ratio of the contraction rates of the affine maps., MAGNES PRESS, 2002, Israel Journal of Mathematics, 127, 1 - 18, web_of_scienceScientific journal

Oscillation maintains polymorphisms - a model of lateral asymmetry in two competing scale-eating cichlids

Scale-eating cichlids in Lake Tanganyika exhibit lateral asymmetry polymorphism in their mouth-opening. Frequency of left- and right-handed phenotypes oscillates around unity. In the southern shore of the lake, two scale-eaters coexist in similar densities, where their oscillations synchronize. This phenomena is analysed by a time-delay differential equation model, and a new mechanism which maintains polymorphism is discovered. In a wide range of parameters, the oscillation keeps the frequencies of the same phenotype in the two species at a similar level, and prevents the fixation of one phenotype in either species. (C) 1998 Academic Press., ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Nov. 1998, JOURNAL OF THEORETICAL BIOLOGY, 195 (1), 1 - 12, doi;web_of_scienceScientific journal

A shape theorem for the spread of epidemics and forest fires in two-dimensional Euclidean space

OSAKA JOURNAL OF MATHEMATICS, Dec. 1996, OSAKA JOURNAL OF MATHEMATICS, 33 (4), 915 - 925, web_of_scienceScientific journal

Minimal cocycles with the scaling property and substitutions

'Fractal' functions are formulated as a minimal cocycle on a topological dynamics which admits nontrivial scaling transformations. In this paper, it is proved that if in addition it admits a continuous family of scaling transformations, then its capacity is not in o(N-2). We define minimal cocycles with nontrivial scaling transformations coming from substitutions on a finite alphabet which are proved to have capacity O(N), so that they admit only a discrete family of scaling transformations. We also construct one which has capacity O(N-2) and admit a continuous family of scaling transformations., MAGNES PRESS, 1996, ISRAEL JOURNAL OF MATHEMATICS, 95, 393 - 410, web_of_scienceScientific journal

Unstable geodesics and topological field theory

A topological field theory is used to study the cohomology of mapping space. The cohomology is identified with the Becchi-Rouet-Stora-Tyutin cohomology realizing the physical Hilbert space and the coboundary operator given by the calculations of tunneling between the perturbative vacua. The method is illustrated by a simple example. © 1994 American Institute of Physics., AMER INST PHYSICS, 1994, Journal of Mathematical Physics, 35 (9), 4547 - 4567, doi;web_of_scienceScientific journal

A variational formula for dimension spectra of linear cellular automata

Space-time patterns of the evolution of linear cellular automata exhibit self-similar patterns. The distribution of fractal dimensions of space patterns is characterized by dimension spectra. Using multifractal formalism, the dimension spectrum is shown to be equal to the Legendre transformation of the free energy. © 1994 Hebrew University of Jerusalem., 1994, J. Analyse Math, 64 (1), 1 - 51, doiScientific journal

Competitive coexistence in a seasonally fluctuating environment II. Multiple stable states and invasion success

ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS, 1993, Theor. Popl. Biol., 44 (3), 374 - 402, web_of_scienceScientific journal

Cellular automata and multifractals: dimension spectra of linear cellular automata

ELSEVIER SCIENCE BV, 1990, Physica D, 45 (1-3), 36 - 48, web_of_scienceScientific journal

Limiting behaviour of linear cellular automata

1987, Proc. Japan Acad., 63A, 182 - 185Dynamics of Laterality in Lake Tanganyika Scale-Eaters Driven by Cross-Predation

Scale-eating cichlid fishes, Perissodus spp., in Lake Tanganyika have laterally asymmetrical bodies, and each population is composed of righty and lefty morphs. Righty morphs attack the right side of prey and lefty morphs do the opposite. This anti-symmetric dimorphism has a genetic basis. Temporal changes in the frequencies of morphs in two cohabiting scale-eating species (Perissodus microlepis and P. straeleni) were investigated over a 31-year period on a rocky shore at the southern end of the lake. Dimorphism was maintained dynamically during the period in both species, and the frequencies oscillated with a period of about four years in a semi-synchronized manner. Recent studies have indicated that this type of anti-symmetric dimorphism is shared widely among fishes, and is maintained by frequency-dependent selection between predator and prey species. The combinations of laterality in each scale-eater and its victim were surveyed. The results showed that “cross-predation”, in which righty predators catch lefty prey and lefty predators catch righty prey, occurred more frequently than the reverse combination (“parallel-predation”). The cause of the predominance of cross-predation is discussed from the viewpoint of the physical and sensory abilities of fishes., MDPI AG, 20 Jan. 2019, Symmetry, 11 (1), 119 - 119, doi;urlScientific journal

生物の形の多様性と進化

裳華房, 2003Macintosh ではじめる C

牧野書店, 1996エルゴード理論とフラクタル

シュプリンガー・フェアラーク東京, 1993Chaos in Australia

World Scientific Publishing, 1993Chaos in Australia

World Scientific Publishing, 1993カオス

サイエンス社, 1990

ニクバエの蛹休眠を誘導する臨界日長の性比の進化

日本応用動物昆虫学会, 2016半倍数性害虫における殺虫剤抵抗性発達

日本応用動物昆虫学会, 2015繁殖干渉を伴う島の生物地理モデル

日本生態学会, 2014樹上性カタツムリの左右二型にみる進化的安定性

日本進化学会, 2013左利きホモはどのように消えていくか ― 魚類左右性多型の不和合性の進化

日本生態学会, 2009リッチなメスは性転換しない?ーツマジロモンガラの性転換の数理モデルー

日本生態学会, 2009ハクセンシオマネキの左右性の遺伝システムのモデル

日本生態学会, 2009Size dependent resource allocation and patterns of sexuality in sedentary marine animals

日本数理生物学会, 2008リッチなメスは性転換しない？

日本動物行動学会, 2008小さい雄は成長するか?-フジツボ類の矮雄の成長パターンと生活史戦略-

個体群生態学会, 2008A model on the evolution of cooperation in an asymmetric prisoner’s dilemma in an intertidal crab

Japanese Society of Mathmatical Biology, 2008同性間伝播と異性間伝播の両方を考えた HIV のモデル

数理生物学会, 2008ハクセンシオマネキの左右性の遺伝システムのモデル

日本数理生物学会, 2008左利きホモはなぜ存在しない？魚類左右性の遺伝システムの進化

行動学会, 2008ハクセンシオマネキの左右性の遺伝システムのモデル

行動学会, 2008Oscillation induces the evolution of homozygote incompatibilities in the lateral asymmetry genetics of fish

The Society of Population Ecology, 2008干潟の蟹における非対称な囚人のジレンマの協力の進化

個体群生態学会, 2008ハクセンシオマネキの左右性の遺伝システムのモデル

個体群生態学会, 2008Size dependent resource allocation and patterns of sexuality in sedentary marine animals

Japanese Society of Mathematical Biology, 2008A model on the evolution of cooperation in an asymmetric prisoner’s dilemma in an intertidal crab

Japanese Society of Mathmatical Biology, 2008Oscillation induces the evolution of homozygote incompatibilities in the lateral asymmetry genetics of fish

The Society of Population Ecology, 2008Oscillation of laterality in prey-predator system with time delay, due to predation or frequency dependence?

CIJK-MB-2019, 2019非効率な軍備は維持されるか? — キヌハダモドキの性的共食いのモデル

日本動物行動学会, 2018Predation or frequency dependence, which of them controls dimorphism oscillations in prey predator system?

Society of Mathematical Biology, 2018