Changes in personality following secondary spread and its causes in a nonindigenous crayfish

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07512
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Ecology/Environment
• Research Institution: Kanazawa University
• Principal Investigator: Nisikawa Usio 金沢大学, 環日本海域環境研究センター, 准教授 (00391136)
• Research Collaborator: Kudou Shuhei ; Kitano Satoshi ; Murota Yoshihiro
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 外来種 / 攻撃行動 / 侵入歴 / 行動シンドローム / Pacifastacus leniusuculs

Outline of Final Research Achievements

The invasive signal crayfish (Pacifastacus leniusuculs) that have established in Japan consists of three founding populations (Hokkaido, Nagano and Shiga Prefectures). Among the three, more recently established populations that originated from the Hokkaido group show enlarged chela size, which are expected to show high aggressiveness. In this study, we tested the hypothesis that “individuals from more recently established populations exhibit higher aggressiveness and activity”. Based on laboratory experiments, we found that aggressiveness, number of approaches and activity were higher in secondary invasive populations relative to the founding population. Hence, aggressiveness and activity of the introduced signal crayfish in Japan considered to have changed following secondary spread from the founding population.

Free Research Field

保全生物学

Academic Significance and Societal Importance of the Research Achievements

侵入種は、ときに、小進化や表現型の可塑性により、新天地で行動形質や形態形質が変化することが知られる。本研究は、侵入ザリガニ類で初めて、これらが二次侵入に伴い、攻撃性や活発さといった行動形質が変化したことを明らかにした研究である。本研究の成果は、侵入ザリガニの駆除管理の際に、優先順位をつける際に有用な情報を提供することが期待される。