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United States Department of Agriculture

Agricultural Research Service


Location: Pollinating Insect-biology, Management, Systematics Research

2013 Annual Report

1a. Objectives (from AD-416):
The overall goal of this project is to ensure the productivity and profitability of insect-pollinated crops by improving the diversity and availability of pollinators for U.S. agriculture. In general terms, we wish to create a toolbox of pollinators. To accomplish this, we seek to understand the diversity and abundance of wild bees in the U.S., and to develop methods for managing a selection of bees as pollinators, including developing effective methods for mass production, ultilization and disease control. To attain our objectives, we plan to focus on specific ecological and agricultural systems. Objective 1: Improve maintenance of wild lands and native bees by (a) enhancing knowledge of native bee pollination, systematics and biodiversity (especially for megachilidae and bombus), (b) developing identification keys that are friendly to non-experts monitoring native bees, and (c) restoring wild lands by identifying the native pollinator guilds necessary for commercial seed farming of native forbs. • Subobjective 1.1. Expand the taxonomy and systematics of native bees, especially Megachilidae, and develop user-friendly identification keys. • Subobjective 1.2. Document the diversity of native bees in the U.S. • Subobjective 1.3. Develop pollination systems for commercial production of native plant seed needed to restore plant communities on public lands in the Intermountain West. Objective 2: Deliver improved pollination management systems for non-apis bees, particularly the Alfalfa Leafcutting Bee (ALCB) and the alkali bee for alfalfa seed production, bumble bees for greenhouse and field crops, and the Blue Orchard Bee (BOB) for orchard crops. • Subobjective 2.1. Improve sustainability of commercial populations of alfalfa leafcutting bees (ALCB) used for alfalfa seed production. • Subobjective 2.2. Improve methods for maintaining alkali bees for alfalfa seed production. • Subobjective 2.3. Improve management methods of Osmia bees for crop pollination, focusing on managing blue orchard bees to pollinate almonds and Osmia aglaia for bramble fruits • Subobjective 2.4. Develop methods to increase retention of managed solitary bees, particularly the blue orchard bee and alfalfa leafcutting bee. • Subobjective 2.5. Develop management methods for bumble bees native to the U.S. Objective 3: Develop effective and grower-friendly systems for managing diseases in non-apis bees, particularly chalkbrood in the ALCB and BOB. • Subobjective 3.1. Determine chalkbrood epidemiology and diversity (through molecular systematics), and elucidate the genetics of bee immune responses and pathogen resistance. • Subobjective 3.2. Discover effective fungicides and other suppression tools,develop application methods for controlling chalkbrood in the ALCB, and use this as a model for chalkbrood control in BOB. • Subobjective 3.3. Discover the key pathogens and parasites that inhibit mass production of bumble bee colonies.

1b. Approach (from AD-416):
Bees are vital to agriculture. The commercial production of more than 90 crops are accomplished through bee pollination. The honey bee is the best known crop pollinator, but recently, honey beekeepers have been facing a bee health crises, and significant scientific time and effort has been put into identifying the cause. The issue can be viewed as a more general problem, one of a declining availability of pollinators for agriculture. As such, another approach to avoiding the crises can be taken, and that is to evaluate the diversity and use of many species of bees. Our plan addresses three main objectives (1) improve native bee diversity and abundance, and knowledge of their biology, (2) deliver improved pollinator management systems, and (3) develop effective disease management systems for non-Apis bees. Our results will develop an understanding of the causes behind pollinator declines, improve pollinator availability, improve crop quality and production for pollinated crops, and enhance the development of new cropping methods (such as covered row crops). Our overriding goal is to provide agriculture with a tool box of pollinators, however, all bees have their own diseases and parasites and are susceptible to environmental use of pesticides and loss of habitat. Research is needed to identify and control the negative impacts of these factors. In addition, many species of wild bees provide free pollination services for agricultural crops and maintain plant reproduction in our rangelands and other natural and wild areas, and thus it is important to evaluate and protect their populations.

3. Progress Report:
Most people are familiar with the importance of bees as pollinators, but many are surprised to learn the U.S. is the native home for about 3700 different species of bees. A better understanding of native bee diversity and biology is important for both agricultural production and ecological conservation. ARS in Logan, UT, contributed towards improving bee identification and classification systems, describing the distribution and biology of different bees and creating digital access to this information. The digital information associated with each specimen in The National Pollinating Insects Collection now includes all the collection data for 1.1 million pinned bees. A phylogenetic tree of mason and orchard bees was developed using DNA from 86 species, using bees in the Collection. This tree of life provides valuable information on the evolution of bee nesting traits and physical characteristics. Bumble bee research conducted in Logan, UT, led to the development of a western species for commercial use, with improved methods for commercial culturing, reducing mortality in the rearing process. U.S. bumble bee populations were evaluated and declining species identified and documented. Bumble bee pathogen prevalence in nature was also documented. Disease control is important for commercial bee production efforts, as well, and ozone was developed as a means for disinfecting nesting materials, especially honey bee comb. Alfalfa leafcutting bees are used extensively for alfalfa pollination, and research was conducted to identify the causes for poor bee reproduction in agricultural fields. Sometimes alfalfa leafcutting bees produce two generations a year, instead of the expected one. This phenomenon was found to increase the spread of chalkbrood, a serious disease of this bee. Studies are needed to determine the environmental causes for second generation development. The alkali bee is also a valuable alfalfa pollinator, and researchers documented farming practices that improve the vitality of alkali bee populations near commercial alfalfa seed fields, showing how agriculture and native bees can sustain each other. Efforts were initiated to determine the types of sublethal effects fungicides and insecticides can have on bees, including studies to determine effects on bee behavior and immune systems. One insecticide formerly thought to be safe for bees was found to affect egg viability when mother bees were exposed. Technology transfer was conducted to make the blue orchard bee, a solitary-nesting bee, more commercially available as a pollinator for orchard crops, especially almonds. ARS researchers have shown how this bee can assist honey bees in pollinating almonds. Tests were also conducted to evaluate the optimal arrangements for blue orchard bee releases into orchards. Bees use chemical cues to identify good nesting locations, and an artificial nest attractant was developed that can be used to retain bees in desired locations. Research also documented the role of native bees in land rehabilitation after disasters, such as wildfires and overgrazing.

4. Accomplishments
1. Chemistry of nesting attractants identified for alfalfa leafcutting bees and blue orchard bees. It has long been known that these two solitary-nesting bees are attracted to old nesting sites. For the blue orchard bee, ARS scientists in Logan, UT and Fargo, ND, identified chemical cues responsible for nest selection, then developed artificial nest attractants based on some of these compounds. A commercial product is currently being evaluated. ARS scientists found that only some components of old nests are attractive to alfalfa leafcutting bees, but have not identified the chemical components of those. Attractants will allow farmers to retain more bees in desired locations.

2. Ozone fumigation as a disinfectant for honey bee comb. ARS scientists in Logan, UT, demonstrated that ozone is useful for decontaminating honey bee supers, as it can break down pesticides, kill insect pests, and kill pathogen spores. Honey bee supers typically get moved between colonies and potentially spread pests and disease, so a decontamination method is needed. Ozone should also prove useful as a means to fumigate alfalfa leafcutting bee nesting boards to reduce the spread of chalkbrood in this managed bee.

3. Immunity-related genes described for the alfalfa leafcutting bee. ARS and University scientists in Logan, UT, conducted the first analysis of immunity-related genes in a solitary bee, and identified 116 genes. Like A. mellifera, M. rotundata were found to have fewer immune response pathways than other insects. These scientists also found that alfalfa leafcutting bees exposed to temperature stress, either chilling or overheating, were more resistant to chalkbrood disease. Stressful temperatures increased the expression of immune response genes, resulting in fewer infections. These immune and stress response genes will provide the background information needed to evaluate the effects of stress on M. rotundata immunity.

4. The blue orchard bee demonstrated as an economically feasible supplement to honey bees for almond pollination. A combination of colony collapse disorder and increased almond acreage has reduced the availability of honey bees for almond pollination. An economic analysis by ARS and University scientists in Logan, UT, found that the recent sharp increase in pollination fees for California almonds can well be explained by the dramatic increase in almond acreage during a period when honey bee colonies in the United States declined. ARS scientists also demonstrated that the blue orchard bee is a very effective pollinator in commercial almond orchards, with pollination costs and almond yields similar to honey bees.

5. Methods developed for propagating and releasing blue orchard bees in large, commercial orchards. ARS scientists in Logan, UT, developed a field incubation box, portable nesting shelters, and protocols for using blue orchard bees to pollinate almonds, apples and cherries. In addition, methods were developed for increasing bee forage by planting early-flowering herbaceous plants in or near orchards. CA almond growers have adapted this approach to extend bee forage for honey bees, as well. Some blue orchard bee producers are propagating these bees in large screened enclosures using the recommended flowers. The potential utility of this bee has spurred the formation of a new organization of blue orchard bee producers and users, the Orchard Bee Association.

6. Western bumble bees developed as greenhouse pollinators. Tomatoes and other crops grown in greenhouses require bumble bee pollinators. Unfortunately, the only commercially available bumble bee is native only to the Eastern U.S., and it may be associated with the accidental introduction of exotic diseases that could potentially affect wild bees in the western U.S. ARS Scientists in Logan, UT, developed methods for the mass production of four Western bumble bees species. As a result of this research, two commercial bumble bee production companies (which supply over 95% of all commercial bumble bees) are developing western species for commercial use.

7. Native bees assist efforts to restore damaged Federal lands. Land managers in the western United States need affordable native plant seed for re-vegetation efforts after wild fires and overgrazing by livestock. ARS scientists experimentally characterized the pollination needs of 12 Western wildflowers, surveyed their native pollinators, and identified pollinators that are practical for the commercial production of these plants as specialty seed crops. This was part of a high profile, multi-agency, federal research program, and has allowed seed growers to produce native plant seeds.

8. Bumble bee declines documented on a continent-wide scale. Bumble bee researchers around the world have noted declines in bumble bees but have not clearly documented such events in the United States. ARS scientists from Logan, UT, with collaborators in Illinois, used data from the labels on bees in insect collections to determine the past geographic range of nine bumble bee species, and then conducted a 3-year field survey to determine current ranges. The Franklin bumble bee can no longer be found, and four other species were found to have declined significantly in both abundance and range, and show signs of developing genetic bottlenecks. As a result of this research, the Franklin bumble bee is now listed as possibly extinct, and the other declining species are considered threatened by the International Union of the Conservation of Nature (IUCN).

9. First nationwide bumble bee pathogen surveys conducted. ARS scientists in Logan, UT, and collaborators in Illinois, conducted a nationwide survey of two key bumble bee pathogens. These pathogens were more prevalent in bumble bee species with declining populations than in species with stable populations, although the pathogens infected many species of bumble bees and were geographically widespread. ARS scientists in Logan, UT, and Beltsville, MD, also found that some honey bee viruses can infect native bumble bees, but it is not clear if these viruses are affecting bumble bee populations. Bumble bee producers can now use this information to identify bumble bee species with low disease susceptibility, making them easier to raise.

10. Revisions and web-based identification tools developed for Nearctic bees. Mason bees (Osmia) are an unusually large group of bees with over 350 species worldwide. These bees are important pollinators in ecosystems, and several species have been developed for use on farms. Only a handful of specialists are competent to properly identify these bees, hampering field ecology studies. ARS scientists in Logan, UT, and collaborators, improved the taxonomy of the Osmia and created web-based identification tools. Numerous new species were discovered in this effort. The web-based identification tools are available on-line (, and proper identifications will contribute towards a better understanding of our native bees.

11. Largest collection of bees in the world. ARS houses the U.S. National Pollinating Insects Collection in Logan, UT, one of the largest collections of bees in the world, containing approximately 1.1 million specimens. This reference collection is visited and used by scientists from all over the world. Data from the insect labels, including the identity, date and time of collection, host plant, gender, etc., has been entered into in a specimen-level relational database for 874,548 of the specimens in the collection, and is available to the scientific community. The ARS dataset is included within the larger, cooperative research tools of the Global Biodiversity Information Facility and DiscoverLife websites, making it broadly available to the scientific community.

Review Publications
Artz, D.R., Allan, M.J., Wardell, G.I., Pitts Singer, T. 2013. Nesting site density and distribution affects Osmia lignaria (Hymenoptera: Megachilidae) reproductive success and almond yield in a commercial orchard.Insect Conservation and Diversity.doi:10.1111/icad.12026

Cane, J.H. 2012. Dung pat nesting by the solitary bee, Osmia (Acanthosmiodes) integra (Megachilidae: Apiformes). Journal of Kansas Entomological Society. 85(3): 262-4.

Gonzalez, V.H., Griswold, T.L. 2013. Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae, Anthidiini) with a phylogenetic analysis of the subgenerea. Zoological Journal of the Linnean Society. 168(2):221-425.

Cane, J.H., Love, B.G., Swoboda, K. 2012. Breeding biology and bee guild of Douglas' dustymaiden, Chaenactis douglasii (Asteraceae, Helenieae). Western North American Naturalist. 72(4):563-568.

Griswold, T.L., Gonzalez, V.H. 2013. A new species of the rare African wool carder bee genus Anthidioma (Hymenoptera: Megachilidae). African Entomology. 21(1):177-180.

Gonzalez, V.H., Engel, M.S., Griswold, T.L. 2013. The lithurgine bees of Australia (Hymentoptera: Megachilidae), with a note on Megachile rotundipennis. Journal of Melittology. 11: 1-19.

James, R.R., Mcguire, M.R., Leland, J.E. 2012. Susceptibility of adult alfalfa leafcutting bees and honey bees to a microbial control agent, Beauveria bassiana. Southwestern Entomologist. 37(1): 13-21.

James, R.R., Ellis, J., Duehl, A.J. 2013. The potential for using ozone to decrease pesticide residues in honey bee comb. Agricultural Science. 1(1): 1-16.

Lebuhn, G., Droege, S., Conner, E.F., Gemmill-Herren, B., Potts, S.G., Minckley, R.L., Griswold, T.L., Jean, R., Kula, E., Roubik, D.W., Cane, J.H., Wetherill, K., Frankie, G., Parker, F. 2012. Detecting insect pollinator declines on regional and global scales. Conservation Biology. 27(1):113-120.

Klinger, E.G., James, R.R., Youssef, N.N., Welker, D.L. 2013. A multi-gene phylogeny provides additional insight into the relationships between several Ascosphaera species. Journal of Invertebrate Pathology. 112:41-8.

Lozier, J., Strange, J.P., Koch, J. 2013. Landscape heterogeneity predicts gene flow in a widespread polymorphic bumble bee, Bombus bifarius (Hymentoptera: Apidae). Conservation Genetics. 14: 1-12.

Koch, J., Strange, J.P., Williams, P. 2012. Bumble bees of the western United States. USDA Forest Service Research Notes. Publication No. FS-972.

Parker, F.D., Griswold, T.L. 2013. New species of the cleptoparasitic bee genus Stelis (Hymenoptera: Megachilidae, Anthidiini) from the Nearctic Region. Zootaxa. 3646:529-544.

Pitts Singer, T. 2013. Intended release and actual retention of alfalfa leafcutting bees (hymenoptera: megachilidae) for pollination in commercial alfalfa seed fields. Journal of Economic Entomology. 106(2):576-86.

Sheffield, C.S., Ratti, C., Packer, L., Griswold, T.L. 2011. Leafcutter and mason bees of the genus Megachile Latreille (Hymenoptera: Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification. 18: 1-106.

Pitts Singer, T. 2013. Variation in alfalfa leafcutting bee (hymenoptera: megachilidae) reproductive success according to location of nests in United States commercial domiciles.. Journal of Economic Entomology. 106(2): 543-51.

Last Modified: 06/21/2017
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