企画シンポジウム

Sex and Ecological Communities

11月14日｜16:00〜18:00 | 言語 [英]

Sex and ecological communities

A variety of phenomena related to sex, including sexual selection, mating behavior, and sex ratio, have been studied to understand the way conspecific individuals interact with one another. Emerging evidence suggests, however, that sex-related phenomena affect not just intra-, but also inter-specific interactions. In some cases, the effects of sex-related phenomena on inter-specific interactions can be so strong as to modify the structure and function of the entire community to which the focal species belongs. In turn, communities can define the ecological context in which sexual traits evolve. In this symposium, speakers will present some new findings on connections between sex and ecological communities. We hope that this symposium will help to identify promising directions for future research.

Organizer: Dr. TSUJI Kaoru, Dr. YAMAMICHI Masato

日本語訳

性と生物群集 - Sex and Ecological Communities (仮題)

性選択や配偶行動、性比など、性にまつわる様々な事象は、種内の個体間相互作用で重要な役割をもつと古くから考えられてきました。しかし研究が進むにつれ、性にまつわる事象は異種間相互作用にも影響を及ぼし、ときには群集構造を決める一因ともなることが報告されるようになってきました。このシンポジウムでは、いくつかの性と群集のつながりについての最新の研究を紹介し、今後の展開について議論を深めたいと考えています。

企画者：辻かおる (京都大学)，山道真人 (University of Queensland)

Linking community ecology to sexual selection and sexual conflict: insights from field studies and experiments with damselflies (Zygoptera)

Erik Svensson (Lund University)

There is an increasing interest in linking community ecology to evolutionary biology and behavioural ecology, reflected in growing fields and popular topics such as reproductive interference, reproductive isolation, speciation and extinction dynamics and sexual selection. Moreover, the field of community ecology has matured and is becoming increasingly similar to evolutionary biology by focussing on a few central mechanisms, similar to population genetics, as reflected in Vellend’s Theory of Ecological Communities, Hubbell’s Neutral Theory of Biodiversity and Chesson’s concepts of stabilizing and equalizing mechanisms. Here, I discuss these developments and connect this to recent empirical and theoretical work in my laboratory, using damselflies (Zygoptera) as our model organisms. In particular, I aim to link interspecific interactions and co-existence mechanisms to the similar processes operating within species. I will also discuss negative frequency-dependence as a general mechanism maintaining both species diversity in communities and genetic diversity within populations.

Coexistence theory with eco-evolutionary dynamics of sex

YAMAMICHI Masato (University of Queensland）

How does rapid evolution of sexual traits affect species coexistence? First, I explain how reproductive interference hinders species coexistence via positive frequency-dependence in community dynamics. This can be weakened by reproductive character displacement, but theoretical studies suggest that the amount of genetic variation is crucial for the completion of displacement as slow evolution results in deterministic extinction. Then, I introduce a new concept, intraspecific adaptation load, to explain how an adaptation to conspecific conflicts can promote species coexistence by negative frequency-dependence in community dynamics. More abundant species is more susceptible to invasion of 'selfish' individuals that increase their own reproductive success at the expense of population growth, and the density-dependent intraspecific adaptation load stabilizes species coexistence.

(日本語訳)

性の生態-進化動態を考慮した共存理論

山道真人 (University of Queensland）

性的形質の迅速な進化は、多種共存にどのように影響するだろうか。繁殖干渉は、正の頻度依存性によって共存を妨げるが、繁殖的形質置換によって弱められる。しかし、進化が遅い場合には置換より先に絶滅が起こるため、遺伝的変異の量が重要となる。一方、個体数が多い種は、性的対立などで個体群増殖よりも自らの繁殖成功を優先する「利己的な」個体に侵入されやすい。そのような密度依存的な種内適応荷重は、負の頻度依存性によって多種共存を安定化させることになる。

Microbes on flowers and pollination

SAKAI Shoho (Kyoto University)

The flower is the device by which plants exchange their pollen. It has nectar, structures to receive pollinator visits and wind, and a germination bed for pollen grains. These characteristics may make the flower vulnerable to microbial infection. How have microbes on flowers affected plant ecology and evolution? In this talk, I will show part of our ongoing studies on bacterial flora on flowers and effects of bacteria inoculation to flowers on the plants. I also discuss how floral microbes can change our views on pollination and plant sexual systems.

(日本語訳)

花の上の微生物と送粉

酒井章子 (京都大学)

花は花粉の授受のための装置である。送粉者の訪花や風を受けやすい構造を持ち、送粉者への報酬となる蜜や花粉の発芽床を備えている。それらの性質はまた、微生物の感染や増殖にも適しているように思われる。花上の微生物は、植物の生態や進化にどのような影響を与えているのだろうか？本講演ではわたしたちが行った花上の細菌叢の解析、接種実験の結果を紹介し、花上微生物研究の今後の展望について紹介したい。

Community-wide consequences of sexual dimorphism in floral traits

TSUJI Kaoru (Kyoto University)

Female and male individuals belonging to a sexually dimorphic species can interact with heterospecific individuals differently. Although intuitive, evidence demonstrating this possibility remains scarce. Focusing on the dioecious plants Eurya japonica and E. emarginata, I will present evidence showing that sexual dimorphism in floral traits exerts surprisingly large effects on the behavior of flower-visiting flies, bees, and other insects, the survival, growth, and evolution of oviposition behavior of flower-feeding moths, and the abundance and community structure of nectar-inhabiting bacteria and yeasts. The resulting changes in the insects and microbes can in turn affect the evolution of floral traits and the reproductive success of the flowers. These findings show how wide-ranging the effects of sexual dimorphism can be in ecological communities.

日本語訳

花の雌雄差と花を利用する昆虫や微生物群集の関係

辻かおる (京都大学)

雌雄間で形質が違う生き物は、同種であっても、性別により他種との相互作用が異なり、その違いは多くの種から成る群集の構造にも影響を及ぼすことがある。その例として、花の形質の雌雄差が訪花昆虫の行動を変えることや花食性昆虫の生死や産卵選好性の進化にも影響を与えること、さらには花蜜に棲む微生物の増殖や群集構造も変えることを紹介する。また、これら他種への影響により、花の適応度や花形質自体の進化にも変化がみられることにも言及したい。

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