Study on the mechanism of biological invasion in ants by focusing on the Japanese invader, Pachycondyla chinensis.

2014 Fiscal Year Final Research Report

• Project/Area Number: 23405011
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Ecology/Environment
• Research Institution: University of the Ryukyus
• Principal Investigator: TSUJI Mizuki 琉球大学, 農学部, 教授 (20222135)
• Co-Investigator(Kenkyū-buntansha): MATSUURA Kenji 京都大学, (連合)農学研究科(研究院), 教授 (40379821) ; TATSUTA Haruki 琉球大学, 農学部, 准教授 (50370268) ; KIKUCHI Tomonori 千葉大学, 海洋バイオシステムセンター, 准教授 (80608547)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: 外来生物 / 生態 / 進化 / 群集 / 社会性昆虫 / アリ

Outline of Final Research Achievements

We aim at comprehensively testing all existing hypotheses of biological invasion in ants by focusing on Brachyponera （Pachycondyla）chinensis that has been invaded from East Asia to North America. Our polulation genetic, chemical and behavioral study revealed that their population and social structure was polygyny-polydomy and multicolonial that was qualitatively the same between the introduced (USA) and the native (Japan) ranges. However, in the USA their density was higher than in Japan. The stable isotope analysis suggested a shift in the trophic level or food niche, i.e. this ant is a specialist hunter of termites in Japan but has become a generalist predator in the USA. The pupal mortality presumably correlated to the infection lord was higher in Japan. Those results suggest that as the mechanism of biological invasion of this ant the ecological release is more important than social insect-specific mechanisms such as genetic bottleneck.

Free Research Field

進化生態学