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United States Department of Agriculture

Agricultural Research Service

Research Project: Managing and Conserving Diverse Bee Pollinators for Sustainable Crop Production and Wildland Preservation

Location: Pollinating Insect-biology, Management, Systematics Research

2015 Annual Report


1a. Objectives (from AD-416):
Objective 1: Improve the production and management of non-Apis bees such as blue orchard bees, bumble bees, and alfalfa leafcutting bees for crop pollination by increasing knowledge of bee nutritional needs and environmental effects on bee physiology (especially on diapause and overwintering). Sub-Objective 1.1: Identify the pollen and nectar requirements for maintaining non-Apis bee fitness, in both native and managed ecosystems. Sub-Objective 1.2: Develop a better understanding of the environmental factors that affect diapause in non-Apis bees, and develop methods to improve winter survival. Objective 2: Identify environmental (e.g. poor nutrition) and biological factors associated with bee declines (non-Apis species and the honey bee) and develop methods to diagnose and control non-Apis mortality, such as pollen ball and chalkbrood, that are caused by parasites, pathogens (e.g. Crithidia and viruses of bumble bees), and pesticides. Sub-Objective 2.1: For non-Apis bees, develop methods to control pests and diagnose and treat infectious diseases. Sub-Objective 2.2: Identify the primary environmental and biological factors that affect managed bee sustainability. Objective 3: Quantify bee forage in relation to floral resources and management practices, such as grazing and improve nesting design and strategies (e.g. using chemical cues to enhance nest location), to maximize bee pollination. Sub-Objective 3.1: Improve the reproduction and health of Megachile rotundata (alfalfa leafcutting bee) and native bees by providing non-crop floral resources. Sub-Objective 3.2: Improve production systems for managed non-Apis bees. Objective 4: Improve bee taxonomy and curation and identify mechanisms that affect bee diversity to enhance conservation efforts, particularly in relation to fire and climate change. Sub-Objective 4.1: Expand the taxonomy and systematics of native bees and develop user-friendly identification keys. Sub-Objective 4.2: Evaluate bee biodiversity and improve the knowledge needed to achieve effective bee conservation and stewardship. Sub-Objective 4.3: Evaluate the effect of habitat-altering events on bee diversity and abundance, especially the effects of fire. Sub-Objective 4.4: Identify climatic factors that define the ranges, phenologies and population persistence of select native bees.


1b. Approach (from AD-416):
Bees are vital to agriculture. The commercial production of more than 90 crops is accomplished through bee pollination. The honey bee is the best known crop pollinator, but unfortunately, honey beekeepers have been facing a recent bee health crisis. Although a significant amount of scientific time and effort has been invested into identifying the causes for poor colony health, the issue can be viewed as a more general problem, the declining availability of pollinators for agriculture and ecosystems. In addition to working toward finding solutions to the health issues facing honey bees, we provide another approach: tapping into the pollination potential of the diverse bee fauna of the U.S. This project plan addresses four main objectives (Fig. 1): (1) improve non-Apis bee production and management systems, (2) develop methods to control pathogens and parasites and identify environmental stressors for all bees, (3) understand the foraging and nutritional needs of non-Apis bees, and (4) improve bee systematics and taxonomy and our knowledge of bee diversity. Our overriding goal is to provide agriculture with a tool box of pollinators. To achieve this, we must provide a better understanding of the causes behind pollinator declines, improve pollinator availability, and better understand how bee population size and density affect crop pollination. Of necessity, this requires addressing diseases and parasites, environmental impacts, and human-induced threats such as pesticides and habitat loss. Equally important is wild bee diversity. Wild bees provide free pollination services for agricultural crops, maintain plant reproduction in natural areas, and ensure a pool of future managed pollinators.


3. Progress Report:
Pollinating Insects—Biology, Management and Systematics Research Unit (PIBMSRU) in Logan, Utah, aims to enhance the understanding, availability, quality, and identification of bees that support U.S. agriculture as pollinators of valuable food and seed crops. In FY2015, PIBMSRU scientists reported on solitary bees and bumble bees in ways that are relevant to stakeholders including alfalfa seed producers, almond growers, bumble bee producers, beekeepers, tomato producers, agencies such as, the Animal and Plant Health Inspection Service Plant Protection and Quarantine Program (APHIS-PPQ), the U.S. Forest Service, the Natural Resources Conservation Service (NRCS), the U.S. Fish and Wildlife Service (FWS), the Bureau of Land Management, and the National Parks Service. Consultation and expertise have been provided to private U.S. citizens concerned with bee health and conservation and to non-profit conservation groups such as the Xerces Society for Invertebrate Conservation, North American Pollinator Protection Campaign, and the Saint Louis Zoo. Bee pollination is critical for the production of fruits, nuts, seeds and vegetables that offer nutrition and taste for humans and livestock. At the PIBMSRU facilities, on public lands, and on private farms and orchards, ARS scientists conduct research to improve bee health and provide pollinators for American agriculture. Of the more than 20,000 bee species worldwide, only a small fraction of species have been successfully managed by humans to pollinate agricultural crops. ARS scientists at PIBMSRU in Logan, Utah, have continued to research to improve the production and management of several species of social and solitary bees that are currently managed or show high potential for management in agricultural systems, and to seek novel pollinators to meet pollination needs. Through agreements with two commercial producers of bumble bees, two species that have not yet been widely commercialized are being developed in the United States. These species which are native to the western United States would allow for the open field use of bumble bees in several states that currently have no options to use Bombus outside of greenhouses. At the same time, solitary species with commercial potential such as two species of mason bees, Osmia sanrafaelae and Osmia aglaia native to the western United States are also being investigated for use in managed systems. Through collaborations with universities and other ARS laboratories, PIBMSRU scientists continue to understand the contributions of unmanaged bees to the pollination of our nation’s crops. This work involves understanding the number of unmanaged bees that occur in agricultural fields and orchards, and requires knowledge of bee taxonomy to accurately determine which species are visiting the target crops. ARS scientists in Logan, Utah, discovered that female Osmia californica bees restricted to pollen producing flowers ingested pollen daily, and by the second week, were maturing and laying full-sized eggs. Conversely, bees with access to only pollen-less sunflowers drank nectar and survived well, but were unable to mature a first egg. Previous nutritional studies of bees have focused on larval needs and the needs of sterile worker honey bees; however, solitary bee eggs are huge, requiring substantial fat and protein relative to honey bees. This work will advise growers who use solitary bees to pollinate their crops that growing small areas of suitable pollen hosts to feed their bees just prior to crop bloom are critical for building populations, so that females are ready to nest and reproduce when crop bloom begins. An ARS scientist in Logan, Utah, with a University of Idaho researcher, investigated the effects of the insect growth regulator novaluron on the alfalfa leafcutting bee, Megachile rotundata. Researchers found increased egg and early larval mortality due to the insect growth regulator. It was further demonstrated that suppression of reproduction in bees persists for up to two weeks after the insecticide is applied to alfalfa plants. Exposure to residuals of this product likely is from the cutting and use of leaf pieces as nesting material. The work is being used by alfalfa seed producers to inform the selection of chemical treatment for control of Lygus in alfalfa seed production. Work to identify biotic and abiotic factors associated with bee declines and health are the focus of PIBMSRU scientists. Despite a critical vacancy in the unit, current studies on the effects of fungicides on bee foraging behavior, nesting behavior, and susceptibility to pathogens are underway. In collaboration with ARS scientists in Mississippi, the effects of fungicides on solitary bees are being studied in large scale cage studies. Routes of exposure of blue orchard bees to fungicides are being investigated with controlled studies to determine the presence and quantity of fungicides in nesting material and pollen provisions. The impacts of fungicides on the bumble bee infection by Nosema bombi, a fungal pathogen, are being determined in the laboratory. An APHIS funded national survey of bumble bee pathogens was conducted in the summer of 2015 and results will help to inform APHIS PPQ regulations on the transport of bumble bees in the United States and internationally. The dietary pollen needs of solitary bees for egg maturation was confirmed using greenhouse trials with Osmia californica confined to pollen-less versus pollen-bearing sunflowers. ARS scientists demonstrated that ooctyes enlarged to the size of laid eggs only for females with pollen access, whereas females without access to pollen did not have sufficient oocyte development. Studies focused on bee forage and pollination continue to be an important and large part of research by PIBMSRU scientists. ARS scientists in Logan, Utah, found that the blue orchard bee is an effective, avid pollinator of red and purple raspberries, the equal of honey bees, and readily provisioned nests with their pollen and nectar. Farmers generally pollinate bramble fruits using rented honeybee hives, but beekeepers’ colony losses are causing rental price escalation. Furthermore, in the Pacific Northwest, cool damp weather during bloom often disfavors honey bee activity, whereas the blue orchard bee is a proven pollinator in adverse conditions. The next studies will evaluate wintering methods to reliably delay spring bee emergence, to synchronize flight with outdoor raspberry bloom. Berry growers in the Pacific Northwest now have a new managed bee to utilize for berry pollination. The efficacy of the blue orchard bee as a pollinator of red and purple raspberries was found to be about equivalent to the honey bee, with several sequential flower visits needed to assure a large fruit. Winter temperatures to will allow holding bees until June raspberry bloom are being investigated. The deployment of blue orchard bees in large almond orchards in California is continuing research at PIBMSRU with FY15 studies focused on the assessing the effects of floral enhancements on reproductive success of blue orchard bees and almond production. To aid the U.S. Forest Service (USFS) and the Bureau of Land Management (BLM) in developing pollinator-friendly seed mixes, PIBMSRU scientists are compiling data from 12 years of sampling of bees at different forbs in and out of wildfires. Flax and yarrow are currently the common additions to seed mixes today; through intensive sampling in 2015, ARS scientists have confirmed that these are poor bee plants that do not serve the objective of bee conservation. A network of native bee researchers was organized by PIBMSRU to assist each USFS Region’s botanist with developing a suitable list of practical bee-friendly wildflowers for their region. A novel calculation was developed to estimate the impact of honey bee competition with native bees for pollen and nectar resources on wildlands. The pollen needs of a large apiary will take away as much pollen as needed to feed several million progeny of solitary bees over an area of about 16 square miles. The taxonomy and systematic of bees is investigated through bee collections data, which is stored at PIBMSRU in the National Pollinating Insect Database of the National Pollinating Insect Collection (NPIC). New work has this collection data is being analyzed in conjunction with another large data set from the American Museum of Natural History to establish a better understanding of bee diversity and distribution across North America. The NPIC is cooperating on broad scaled inventory and monitoring projects with the U.S. Geological Survey (USGS), FWS, Utah Cooperative Agricultural Pest Survey Program (CAPS), the National Parks system and other USDA facilities, providing study design and bee identification, including training of personnel for universities and other federal agencies in study design and bee identification. World revisions and descriptions of new species within Serapista [African bee genus], Afranthidium and Pachyanthidium [Eurasian distribution] are in progress. Orchid bees found in southern United States. While conducting bee inventories ARS researchers in Logan, Utah, found Eufriesea coerulescens in western Texas and southern New Mexico. An inventory of the bees of the United States remains incomplete even at the generic level. Orchid bees, an exclusively Neotropical tribe, have rarely been encountered in the U.S. The genus Eufriesea has rarely been found in states along the Mexican border and never north of the border. While most reports suggest these bees are vagrants, the presence of this bee in two localities suggests it may be a resident member of the U.S. bee fauna.


4. Accomplishments
1. Bumble bee pollen diet is more restricted than honey bees. In an ARS led study in conjunction with Utah State University collaborators in Logan, Utah, researchers found that bumble bees forage for less diverse sources of pollen versus co-located honey bees both within weekly samples and across the season. However, individual bumble bees were more likely to visit multiple pollen sources within a foraging trip than individual honey bee workers. Thus, pollen diet requirements when installing floral provision strips on crop land should be sufficiently broad to feed multiple species of bees.

2. Insect growth regulator used for Lygus control increased brood mortality in alfalfa leafcutting bees. An ARS scientist in Logan, Utah, with a University of Idaho researcher, investigated the effects of the insect growth regulator novaluron on the alfalfa leafcutting bee, Megachile rotundata. Researchers found increased egg and early larval mortality due to the insect growth regulator. It was further demonstrated that suppression of reproduction in bees persists for up to two weeks after the insecticide is applied to alfalfa plants. Exposure to residuals of this product likely is from the cutting and use of leaf pieces as nesting material. The work is being used to inform the selection of chemical treatment for control of Lygus in alfalfa seed production.

3. World class bee collection expanded. Essential information on the biology and distribution of native bees is needed both for managing bees and conserving them and the services they provide. Institutional collections of bees are invaluable resources for ascertaining the status of the pollinators essential for successful reproduction of plants in agricultural and natural environments. ARS houses the U.S. National Pollinating Insects Collection in Logan, Utah, the largest collection of bees in the world, containing approximately 1.4 million specimens from 136 countries. Data from the insect labels, including the identity, date and time of collection, host plant, and gender, has been entered into a specimen-level relational database which now totals 1,108,677 records. This reference collection is visited and used by scientists from all over the world, and the data on pollinators is made available to the public and the scientific community through the Global Biodiversity Information Facility and Discover Life websites.

4. Alpine bumble bee populations in the North Coast and Cascades Network of U.S. National Parks represent genetically distinct island-like populations. An ARS scientist in Logan, Utah, led a team of collaborators at Utah State University and Washington State University demonstrating that bumble bee species restricted to high elevation sites in Olympic National Park, North Cascades National Park, and Mount Rainier National Park each have distinct genetic structure. Degradation of alpine habitat through global climate change could further fragment populations, reducing gene flow among the parks. Additionally, models of future climate suggest that suitable habitat will decrease for several bumble bee species, while low elevation species should see an increase in habitat. These results have been shared with the the National Park Service for use in interpretive material in the parks and to inform land management decisions and species conservation measures in the parks.


Review Publications
Hatten, T.D., Looney, C.N., Strange, J.P., Bosque-Perez, N. 2013. Bumble bee fauna of Palouse Prairie: survey of native bee pollinators in a fragmented ecosystem. Journal of Insect Science. 13(1):26.

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.

Pitts Singer, T. 2015. Resource effects on solitary bee reproduction in a managed crop pollination system. Environmental Entomology. 44(4):1125-1138.

Artz, D.R., Allan, M.J., Wardell, G.I., Pitts Singer, T. 2014. Influence of nest box color and release sites on Osmia lignaria (Hymenoptera: Megachilidae) reproductive success in a commercial almond orchard. Journal of Economic Entomology. 107:2045-2054.

Cane, J.H. 2014. The oligolectic bee Osmia brevis sonicates Penstemon flowers for pollen: a newly documented behavior for the Megachilidae. Apidologie. 45:678-684.

Blaker, E., Strange, J.P., Monroy, F., James, R.R., Cobb, N. 2014. PCR reveals high prevalence of non-sporulating Nosema bombi(Microsporidia) infections in bumble bees (Bombus)in northern Arizona. Journal of Invertebrate Pathology. 123:25-33.

Geib, J., Strange, J.P., Galen, C. 2015. Bumble bee nest abundance, foraging distance, and host-plant reproduction: implications for management and conservation. Ecological Applications. 25(3):768-778.

Holden, A.R., Koch, J.B., Griswold, T.L., Erwin, D.M., Hall, J. 2014. Leafcutter bee nests and pupae from the Rancho La Brea Tar Pits of southern California: Implications for understanding the paleoenvironment of the Late Pleistocene. PLoS One. 9(4):e94724.

Orr, M.C., Koch, J.B., Griswold, T.L., Pitts, J.P. 2014. Taxonomic utility of environmental niche models for species distinction: A case study in Anthophora (Heliophila) (Hymenoptera: Apidae). Zootaxa. 3846:411-429.

Koch, J.B., Love, B.G., Klinger, E.G., Strange, J.P. 2014. The effect of photobleaching on bee (Hymenoptera: Apoidea) setae color and its implications for studying aging and behavior. Journal of Melittology. 38:1-9.

Strange, J.P. 2015. Bombus huntii, Bombus impatiens and Bombus vosnesenskii (Hymenoptera: Apidae) pollinate greenhouse-grown tomatoes in western North America. Journal of Economic Entomology. 108(3):873-879.

Frankie, G., Vinson, S., Rizzardi, M., Griswold, T.L., Coville, R., Grayum, M., Martinez, L.E., Foltz-Sweat, J., Pawelek, J. 2013. Relationships of bees to host ornamental and weedy flowers in urban northwest Guanacaste Province, Costa Rica. Journal of Kansas Entomological Society. 86:325-351.

Tepedino, V.J., Mull, J., Griswold, T.L., Bryant, G. 2014. Reproduction and pollination of the endangered dwarf bear-poppy Arctomecon humilis (Papaveraceae)across a quarter century: unraveling of a pollination web? Western North American Naturalist. 74(3):311-324.

Oneill, K.M., Delphia, C.M., Pitts Singer, T. 2015. Seasonal trends in the condition of nesting females of a solitary bee: wing wear, lipid content, and oocyte size. PeerJ. 3:e930.

Woodard, S., Lozier, J., Goulson, D., Williams, P., Strange, J.P., Jha, S. 2015. Molecular tools and bumble bees: revealing hidden details of ecology and evolution in a model system. Molecular Ecology. 24(12):2916-2936.

Klinger, E.G., Vojvodic, S., Degrandi-Hoffman, G., Welker, D., James, R. 2015. Mixed infections illustrate virulence differences between host-specific bee pathogens. Journal of Invertebrate Pathology. 129:28-35.

Griswold, T.L. 2015. A review of Trachusoides Michener and Griswold (Hymenoptera: Megachilidae). Zootaxa. 3949(1):147-150.

Last Modified: 09/20/2017
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