The findings, which will be published in the November/December 2009 issue of Crop Science, offer promise for the use of bumble bee crop pollinators as an alternative to European honey bees, whose populations have recently declined in many areas of the United States.
Red clover, which is grown for forage and as a rotation crop to improve soil, is raised for seed in western Oregon's Willamette Valley. It will not produce seed without pollination, so growers typically place two to five European honey bee hives on each hectare. However, bee diseases, mites, and colony collapse disorder have recently limited availability and resulted in higher costs for hive rentals. Given these changes, an alternative pollinator for red clover seed crops is needed.
Worldwide there are over 200 species of bumble bees; some of whom are known to pollinate red clover. While commercially reared bumble bee species are available to growers elsewhere, they are considered exotic species in Oregon and cannot be introduced into the state. This leaves Oregon growers dependent on naturally occurring populations of bumble bees as pollinators. However, there is currently no information on the pollination efficiency of native bumble bee species.
Through funding from the Clover Commission, scientists at Oregon State University investigated native bumble bees in commercial fields of red clover seed crops in the Polk County region of the Willamette Valley. Prior to bloom, researchers covered plants with mesh-screened cages. European honey bee hives were placed in some cages and nests of B. vosnesenskii, a native Oregon bumble bee,in others. Some cages were also left vacant. After bloom, seed yield and seed set were compared amongst the different cages. Seed set was also evaluated in four different fields without cages to assess the efficiency of existing bee pollinators. In addition to analyzing seed set, researchers assessed the diversity and abundance of native bumble bees through visual observations of foragers on red clover flowers and through trapping bumble bees in blue vane traps.
While there were no differences in seed yield or average seed set in cages with bumble bees compared to honey bees, the study revealed that variability across cages was lower with bumble bees indicating that bumble bee pollination is more uniform than pollination by European honey bees. The researchers observed that the abundance of bumble bee peaked during mid-to-late bloom. They recorded six species of bumble bees gathering pollen from red clover flowers. Of these, more than 92 percent consisted of B. vosnesenskii, indicating that it is the key pollinator in Oregon. In addition to the six native bumble bee species that were seen gathering pollen from the red clover, 25 more species of native solitary bees, belonging to 12 genera and five families, were collected in the bee traps.
The study has not only documented a great diversity of native bees in synchrony with red clover bloom, but it has also found that seed set was uniform and high across four fields. Under current pollinator regimes, researchers believe red clover seed production is close to its maximum in Oregon.
"To sustain these high yields in Oregon, we must conserve the habitat of bees, use pesticides judiciously and provide floral resources prior to red clover bloom," said Oregon State University entomologist Sujaya Rao, one of the researchers on the study. "Globally, where red clover seed is produced, similar studies are needed. If seed set is found to be well below the maximum, appropriate alternative options such as augmentation with commercial bumble bees could be considered."
Research is ongoing at Oregon State University to determine whether high yields can be achieved by native pollinators alone. If so, European honey bee hive rentals would not be required, and this could lead to more economic red clover seed production in Oregon.
The full article is available for no charge for 30 days following the date of this summary. View the abstract at http://crop.scijournals.org/cgi/content/abstract/49/6/2207.
Crop Science is the flagship journal of the Crop Science Society of America. Original research is peer-reviewed and published in this highly cited journal. It also contains invited review and interpretation articles and perspectives that offer insight and commentary on recent advances in crop science. For more information, visit http://crop.scijournals.org.
The Crop Science Society of America (CSSA), founded in 1955, is an international scientific society comprised of 6,000+ members with its headquarters in Madison, WI. Members advance the discipline of crop science by acquiring and disseminating information about crop breeding and genetics; crop physiology; crop ecology, management, and quality; seed physiology, production, and technology; turfgrass science; forage and grazinglands; genomics, molecular genetics, and biotechnology; and biomedical and enhanced plants.
CSSA fosters the transfer of knowledge through an array of programs and services, including publications, meetings, career services, and science policy initiatives.
Sara Uttech | Newswise Science News
Trees and climate change: Faster growth, lighter wood
14.08.2018 | Technische Universität München
Animals and fungi enhance the performance of forests
01.08.2018 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences