Symposium of Behavioral Ecology: Social Insects and Beyond

行動生態学シンポジウム ―社会性からその先へ―


共催:日本生態学会近畿地区会

 ミツバチやアシナガバチ、アリやシロアリなどの社会性昆虫は、社会生活を営むという特徴をもち、同じく社会性を持つ我々人類も古くからその生活に関心をよせてきました。特に、繁殖を行わないワーカー(労働階級)が存在するという事実は、「利他行動」として進化生物学上の大きなパラドクスとされ、現在でも活発な議論が繰り広げられています。近年の技術革新に伴い、かれらの社会システムをその分子基盤から高精度に解き明かす分子生物学・ゲノム科学・生物情報科学研究の道が拓かれ、社会性昆虫は分野横断的研究の新たなモデル生物としての地位を確立しつつあります。

 このたび、インド科学アカデミー前会長で著名な社会性昆虫学者であるRaghavendra Gadagkar教授の来日にあわせ、相互の研究発表を通じて研究交流をはかるシンポジウムを企画しました。発表形式として口頭とポスターの双方を設け、次代を担うべき若手からの発表を広く募ることで、熱い議論と実り多い交流の場となるように配慮いたしました。シンポジウム後には懇親会を予定しています。

 みなさまの積極的なご参加をお待ちしております。



Program
23 February, 2019 (Lecture Hall, Science Seminar House, Graduate School of Science, Kyoto University)

 10:00  KOBAYASHI, Kazuya
 (Kyoto University)
 Opening Remarks
 10:15  GADAGKAR, Raghavendra
 (Indian Institute of Sciences)
 Keynote lecture: Direct fitness options for ‘sterile’ workers in the primitively eusocial wasp Ropalidia marginata
 11:15  TSUCHIDA, Koji
 (Gifu University)
 Social and genetic colony structure in an Australian paper wasp Ropalidia plebeiana
 11:45  Lunch
 13:00  YANG, Chin-Cheng Scotty
 (Kyoto University)
 Ant and myrmecophiles: a potential route for horizontal transmission of Wolbachia
 13:30  GOTOH, Ayako
 (Konan University)
 Role of queen’s spermatheca for long-term sperm storage in ants
 14:00  AKINO, Toshiharu
 (Kyoto Institute of Technology)
 Cuticular lipids as communication tools in ants
 14:30  Break
 14:45  KOBAYASHI, Kazuya
 (Kyoto University)
 Mating competition and biodiversity connected by multilevel selection
 15:15  MATSUURA, Kenji
 (Kyoto University)
 Genomic imprinting drives the evolution of eusociality
 15:45  YAMANE, Seiki
 (Kagoshima University)
 Looking into ant diversity in Southeast Asia
 16:15  DOBATA, Shigeto
 (Kyoto University)
 Concluding Remarks
 16:30-18:30  Poster Session
 19:00-21:00  Banquet “Camphora” (University Cafeteria in front of the clock tower)



Keynote lecture:
Direct fitness options for ‘sterile’ workers in the primitively eusocial wasp
Ropalidia marginata

Raghavendra Gadagkar,
(Centre for Ecological Sciences and Centre for Contemporary Studies, Indian Institute of Science, Bangalore)

  Workers in social insect colonies forgo reproduction and spend their lives working to rear their queen’s brood. Such altruistic sterility is a hallmark of insect societies and the reason why they have captured the attention of evolutionary biologists. Inclusive Fitness theory shows that such altruistic sterility can be favoured by natural selection if workers can gain indirect fitness by working for close genetic relatives. The popularity of this inclusive fitness theory has preoccupied social insect biologists in studying how and when workers can gain indirect fitness. But it has also unfortunately led to a near complete neglect of the possibility that workers might even get some direct fitness.
  This situation has prompted us to study the various options for direct reproduction for workers in the primitively eusocial wasp Ropalidia marginata. Workers in primitively eusocial insects may have three options for gaining direct reproduction. The first is to lay eggs even in the presence of the queen. The second is to leave the parent colony to found new nests of their own. The third is to replace their queens and take over the colony as its next queen. However, new nest foundation and queen succession are quite common. We have studied the phenomenon of nest foundation by observing the natural tendencies of the wasps to found nests, by forcing every member of the colony to found nests and by isolating virgin wasps singly, in pairs or in triplets to examine the dynamics of nest foundation and to understand the role of colony size and behavior in the success of newly founded nests.
  We have also found that workers routinely replace their old, and sometimes not so old, queens. Indeed, such queen succession seems to be the main way for an individual to become a queen in this species. We have also shown that there are well-organized, predetermined reproductive queues with workers waiting their turn to replace successive queens in a surprisingly orderly manner.
  Our results show that direct fitness, through nest foundation and queen succession may be an important option for workers in Ropalidia marginata. This should facilitate the evolution of sociality even more because workers can have both direct as well as indirect fitness.




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