Alternative Pollinator Taxa Are Equally Efficient but Not as Effective as the Honeybee in a Mass Flowering Crop

• Published in: The Journal of applied ecology 2009-10, Vol.46 (5), p.1080-1087
• Main Authors: Rader, Romina, Howlett, Bradley G., Cunningham, Saul A., Westcott, David A., Newstrom-Lloyd, Linda E., Walker, Melanie K., Teulon, David A. J., Edwards, Will
• Format: Article
• Language: English
• Subjects: Alternative pollinators; Animal productions; Animal, plant and microbial ecology; Apiculture; apidae; Apis mellifera; Applied ecology; Bees; Biological and medical sciences; Bombus terrestris; Brassica; Brassica rapa; Bumblebees; Crop science; Crops; Dilophus; diptera; Eristalis; Eristalis tenax; Flower stigma; Flowers & plants; Fundamental and applied biological sciences. Psychology; General aspects; Honey bees; hymenoptera; Insect pollination; Insecta; Invertebrates; Leioproctus; Plant reproduction; Pollen; Pollinating insects; Pollination; Pollination and Biocontrol; syrphidae; Taxa; Terrestrial animal productions; unmanaged; Varroa destructor; wild
• ISSN: 0021-8901; 1365-2664
• DOI: 10.1111/j.1365-2664.2009.01700.x

1. The honeybee Apis mellifera is currently in decline worldwide because of the combined impacts of Colony Collapse Disorder and the Varroa destructor mite. In order to gain a balanced perspective of the importance of both wild and managed pollination services, it is essential to compare these services directly, a priori, within a cropping landscape. This process will determine the capacity of other flower visitors to act as honeybee replacements. 2. In a highly modified New Zealand agricultural landscape, we compared the pollination services provided by managed honeybees to unmanaged pollinator taxa (including flies) within a Brassica rapa var. chinensis mass flowering crop. 3. We evaluate overall pollinator effectiveness by separating the pollination service into two components: efficiency (i.e. per visit pollen deposition) and visit rate (i.e. pollinator abundance per available flower and the number of flower visits per minute). 4. We observed 31 species attending flowers of B. rapa. In addition to A. mellifera, seven insect species visited flowers frequently. These were three other bees (Lasioglossum sordidum, Bombus terrestris and Leioproctus sp.) and four flies (Dilophus nigrostigma, Melanostoma fasciatum, Melangyna novae-zelandiae and Eristalis tenax). 5. Two bee species, Bombus terrestris and Leioproctus sp. and one fly, Eristalis tenax were as efficient as the honeybee and as effective (in terms of rate of flower visitation). A higher honeybee abundance, however, resulted in it being the more effective pollinator overall. 6. Synthesis and applications. Alternative land management practices that increase the population sizes of unmanaged pollinator taxa to levels resulting in visitation frequencies as high as A. mellifera, have the potential to replace services provided by the honeybee. This will require a thorough investigation of each taxon's intrinsic biology and a change in land management practices to ensure year round refuge, feeding, nesting and other resource requirements of pollinator taxa are met.