Elucidation of factors in the expansion of the distribution range and population size of the socially parasitic hornet Vespa dybowskii

2015 Fiscal Year Final Research Report

• Project/Area Number: 25440248
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Ecology/Environment
• Research Institution: Forestry and Forest Products Research Institute
• Principal Investigator: SAYAMA KATSUHIKO 国立研究開発法人 森林総合研究所, 北海道支所, 主任研究員 (70353711)
• Co-Investigator(Kenkyū-buntansha): MOROOKA Fuki 茨城大学, 理学部, 准教授 (70635755) ; KOJIMA Jun-ichi 茨城大学, 理学部, 教授 (00192576)
• Research Collaborator: MAKINO Shun'ichi
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 社会寄生 / 個体群 / チャイロスズメバチ / 分布拡大 / 生息密度 / 人為的移動 / 宿主転換

Outline of Final Research Achievements

We investigated the factors in the expansion of the distribution range and population size of the socially parasitic hornet Vespa dybowskii in Japan. The haplotype analyses suggested that artificial transfer of the overwintered queens from Honshu to Hokkaido (or vice versa) has not occurred. The recent expansion of its distribution range either in Hokkaido and Honshu would be of the host-species switch from V. crabro to V. simillima. While the recorded hosts at about 60 years ago were nearly always V. crabro, recent host records show that more than 60% of the host hornet species are V. simillima. The population sizes of V. simillima have recently increased in urban areas, whereas those of V. crabro have decreased in various regions in Japan. These findings suggest that a possible switch in the principal host from V. crabro to V. simillima is one of the factors underlying the rapid range expansion and increase in the population size of V. dybowskii.

Free Research Field

昆虫生態学