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Insights from measuring pollen deposition: quantifying the pre-eminence of bees as flower visitors and effective pollinators

Willmer, P. G.; Cunnold, H.; Ballantyne, G.


P. G. Willmer

H. Cunnold


Using our accumulated datasets from Kenyan savanna, Mediterranean garigue, UK gardens and heathland, involving 76 plants from 30 families, we present detailed data to quantify the superiority of bees as pollinators of most flowering plants when compared with other flower visitors. Bees provided the majority of visits to study species at all sites, and 33 of the 76 plants received more than 90% of their visits from bees. Furthermore, pollen deposition onto stigmas from single-visit events (SVD, a measure of pollination effectiveness) was significantly higher for bees than non-bees at all the four sites where a major proportion of the flora was sampled. Solitary bees, and also bumblebees in temperate habitats, were the best potential pollinators for most plants in this respect, and significantly out-performed honeybees. Only a few plants were well served by bombyliid flies, and fewer again by larger hoverflies, butterflies, or solitary wasps. Bees also achieved better matches of their visit timing to peak pollen availability (measured indirectly as peak SVD), and made much shorter visits to flowers than did non-bees, permitting a substantially greater visit frequency. Additionally, they deposited significantly lower levels of potentially deleterious heterospecific pollen on stigmas in heathland and Mediterranean garigue, though not in the UK garden with densely clustered high-diversity flowering, or in the Kenyan savanna site with particularly dispersed flowering patches and some specialist non-bee flowers. Our data provide a novel and quantified characterisation of the specific advantages of bees as flower visitors, and underline the need to conserve diverse bee communities.


Willmer, P. G., Cunnold, H., & Ballantyne, G. (2017). Insights from measuring pollen deposition: quantifying the pre-eminence of bees as flower visitors and effective pollinators. Arthropod-Plant Interactions, 11(3), 411-425.

Journal Article Type Article
Acceptance Date Apr 18, 2017
Online Publication Date May 6, 2017
Publication Date May 6, 2017
Deposit Date May 11, 2017
Publicly Available Date May 15, 2017
Journal Arthropod-Plant Interactions
Print ISSN 1872-8855
Electronic ISSN 1872-8847
Publisher BMC
Peer Reviewed Peer Reviewed
Volume 11
Issue 3
Pages 411-425
Keywords Pollination, pollen, deposition, Bees, flower visit duration, visit timing, Heterospecific pollen Int
Public URL
Contract Date May 11, 2017


Insights from measuring pollen deposition: quantifying the pre-eminence of Bees as flower visitors and effective pollinators (588 Kb)

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© The Author(s) 2017 Open Access
This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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