1993 Fiscal Year Final Research Report Summary

A STUDY OF TWO POLLINATORS-MEDIATED SELECTION ON COROLLA TUBE LENGTH

Research Project

Project/Area Number	04640610
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	生態学
Research Institution	TOKYO METROPOLITAN UNIVERSITY
Principal Investigator	SUZUKI Kazuo 東京都立大学, 理学部植物系統分類学, 助手 (50187712)
Project Period (FY)	1992 – 1993
Keywords	bumblebee / flower tube length / Isodon umbrosus / natural selection / マルハナバチ
Research Abstract	Pollinator-mediated selection on corolla tube length of Isodon umbrosus was measured through female reproductive success. Results showed that selection directs for longer corollas. Length matching between functional proboscis (glossa or glossa+prementum) of pollinators and corolla tube of the plants are important factors for high seed-set of the long tube flowers. B.diversus or rarely B.consobrinus pollinates the flowers with the long corolla tubes of which lengths correspond to the pollinators' glossa lengths. B.honshuensis is also a pollinator of the long tube flowers although corresponding lengths to such long corolla tubes are glossa+prementum. Flowers with short corolla tubes are pollinated by B.honshuensis when this bee sucks nectar using glossa only. Long tube flowers are pollinated by three bumblebee species, while short tube flowers are pollinated only by one bumblebee species of the three.