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Competitive impacts of an invasive nectar thief on plant-pollinator mutualisms

June 1, 2014

Plant–pollinator mutualisms are disrupted by a variety of competitive interactions between introduced and native floral visitors. The invasive western yellowjacket wasp, Vespula pensylvanica, is an aggressive nectar thief of the dominant endemic Hawaiian tree species, Metrosideros polymorpha. We conducted a large-scale, multiyear manipulative experiment to investigate the impacts of V. pensylvanica on the structure and behavior of the M. polymorpha pollinator community, including competitive mechanisms related to resource availability. Our results demonstrate that V. pensylvanica, through both superior exploitative and interference competition, influences resource partitioning and displaces native and nonnative M. polymorpha pollinators. Furthermore, the restructuring of the pollinator community due to V. pensylvanica competition and predation results in a significant decrease in the overall pollinator effectiveness and fruit set of M. polymorpha. This research highlights both the competitive mechanisms and contrasting effects of social insect invaders on plant–pollinator mutualisms and the role of competition in pollinator community structure.

Citation Information

Publication Year 2014
Title Competitive impacts of an invasive nectar thief on plant-pollinator mutualisms
DOI 10.1890/13-1276.1
Authors Cause Hanna, David Foote, Claire Kremen
Publication Type Article
Publication Subtype Journal Article
Series Title Ecology
Index ID 70111767
Record Source USGS Publications Warehouse
USGS Organization Pacific Island Ecosystems Research Center