Canadian Forest Service Publications

Willows (Salix spp.) as pollen and nectar sources for sustaining fruit and berry pollinating insects. 2015. Ostaff, D.P.; Mosseler, A.; Johns, R.C.; Javorek, S.; Klymko, J.; Ascher, J.S. Canadian Journal of Plant Science 95: 505-516.

Year: 2015

Available from: Atlantic Forestry Centre

Catalog ID: 36159

Language: English

CFS Availability: PDF (request by e-mail)

Available from the Journal's Web site.
DOI: 10.4141/CJPS-2014-339

† This site may require a fee.

Abstract

Willows (Salix spp.) are ubiquitous in the northern hemisphere, serving as important pollen and nectar resources for insect pollinators and for the enhancement of insect-pollinated agricultural crops such as fruits and berries. We used a common-garden field test containing seven native North American willow species to assess attractiveness of male and female flower catkins by documenting visits of common wild bees and flower flies. Most willows in Canada’s Maritimes begin flowering very early in spring, as the first wild pollinators become active following winter, and stop flowering by mid-May. A later-flowering group normally begins flowering in mid-May and stops flowering by mid-June. Pollinator species were largely opportunistic, visiting whatever species of willow flowers were available during foraging. There was a general preference for male flower catkins because pollen is the major component of nest provisioning for most solitary bees and the major source of protein used to develop reproductive tissues in most flower flies. Most insect pollinators were collected within the April–June flowering period of six of the seven willow species studied, indicating that these willows could be used to support pollinator communities before the flowering period of commercially valuable flower-pollinated crops such as lowbush blueberry, cranberry, and apple. The importance of insect pollinators to natural land reclamation processes such as the invasion and colonization of highly disturbed areas such as mine sites by flowering herbaceous plants was also highlighted in this study.

Plain Language Summary

Willows (Salix spp.) are ubiquitous in the northern hemisphere, serving as important pollen and nectar resources for insect pollinators and for the enhancement of insect-pollinated agricultural crops such as fruits and berries. We used a common-garden field test containing seven native North American willow species to assess attractiveness of male and female flower catkins by documenting visits of common wild bees and flower flies. Most willows in Canada’s Maritimes begin flowering very early in spring, as the first wild pollinators become active following winter, and stop flowering by mid-May. A later-flowering group normally begins flowering in mid-May and stops flowering by mid-June. Pollinator species were largely opportunistic, visiting whatever species of willow flowers were available during foraging. There was a general preference for male flower catkins because pollen is the major component of nest provisioning for most solitary bees and the major source of protein used to develop reproductive tissues in most flower flies. Most insect pollinators were collected within the April–June flowering period of six of the seven willow species studied, indicating that these willows could be used to support pollinator communities before the flowering period of commercially valuable flower-pollinated crops such as lowbush blueberry, cranberry, and apple. The importance of insect pollinators to natural land reclamation processes such as the invasion and colonization of highly disturbed areas such as mine sites by flowering herbaceous plants was also highlighted in this study.

Date modified: