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.
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: (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.
Our research unit 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 addition, we investigate the role of native bees in natural ecosystems and how to enhance their conservation, ensuring their provision of ecosystem services. In FY2017, we reported on solitary bees, bumble bees, and honey bees of relevance to the general public, alfalfa seed producers, almond growers, fruit growers, bumble bee producers, honey bee keepers, tomato producers, and agencies such as: the Animal and Plant Health Inspection Service (APHIS) Plant Protection and Quarantine Program, the U.S. Forest Service (USFS), the Natural Resources Conservation Service (NRCS), the U.S. Fish and Wildlife Service (FWS), the Bureau of Land Management (BLM), the National Parks Service (NPS), U.S. Geological Services (USGS), and U.S. Environmental Protection Agency (EPA). Consultation and expertise have been provided to private citizens and to non-profit conservation groups such as the Xerces Society for Invertebrate Conservation, North American Pollinator Protection Campaign, and the St. Louis Zoo. We provide consultation to the Tribal Pesticide Program Council representing Native American Nations with guidance on Managed Pollinator Protection Plans. We have also helped to inform regulatory agencies and ag/chem industries on the biology of native bees and how their risk of exposure to agrichemical products may be potentially greater than honey bees, given major differences in nesting and provisioning behaviors. We have helped to educate ag/chem industries (such as Bayer Corporation) about native bee biology and methods. With increased focus on native bees within USDA, we have actively participated in discussions, development of methods, and design of native bee surveys. We have developed and presented for the first time a workshop on native bee surveys to members of Tribal Nations, with the goal of educating about native bees and their role in agricultural and natural ecosystems and to provide the needed information to perform surveys. This workshop can be adapted in the future for other audiences. Of the more than 20,000 bee species worldwide, only a small fraction of species have been successfully managed to pollinate agricultural crops. ARS scientists at PIBMSRU continue research to improve production and management of several species of social and solitary bees currently managed in agricultural systems, and to seek novel pollinators to meet pollination needs. Comparative studies are being performed to understand how environmental stresses and pathogens affect health of honey bees, bumble bees, and solitary bees in agricultural environments. Through collaborations, our scientists continue to understand the contributions of unmanaged bees to pollination of our nation’s crops and natural ecosystems. This requires knowledge of bee taxonomy to accurately determine which species are visiting the target crops in orchards and fields. Development of methods for native bee identification is needed to aid the non-specialists and aid in conservation. For FY17, we have made significant progress toward our four goals: (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. For improved non-Apis bee production and management systems, we have made significant progress toward using the Blue Orchard Bee (BOB) (Osmia lignaria) in crop production. In almonds, research has found that BOBs when co-deployed with honey bees result in an increased fruit set. Economic models using the data have been developed and can help growers explore the inputs into the almond systems and the effects of adding BOB’s. The management and deployment of BOBs benefited from even distribution of smaller nesting boxes with nesting tubes across orchards. Use of ARS-patented spray-on-lure for nesting encouraged BOBs to stay in orchards and effectively pollinate the crop. (Lure licensed by Hunter Bees dba Crown Bees, DN 0143.12 - LN – 1711 in FY17). The methods and practices for using BOBs has been transferred to commercial companies managing BOBs and the services of these companies is now in demand by numerous almond growers. For both almonds and tart-cherries, increased production of BOBs resulted from greater nesting accompanying the use of the smaller nest boxes at a higher distribution density in the orchard; this is important since it is a major indication that sustainable production of the bees themselves may be possible in the crop itself. For several crops, we have collaborated with university and non-governmental organizations to develop “Integrated Crop Pollination” (ICP) strategies to maximize profits and ensure sustainable pollination of bee-dependent crops. ICP emphasizes combining tactics that are appropriate for a crop’s dependence on insect-mediated pollination and include the use of wild and managed bee species and enhancing the farm environment for pollinators through directed habitat management and pesticide stewardship. ICP allows for flexible options and provides support tools that consider crop value, yield benefit from adoption of ICP components, and cost of the practices. This approach has been transferred to growers to enable them to decide on the most efficient way to apply ICP to maximize profits for their farms and crops. We characterized populations of different bumble bee species and cavity nesting bees in agricultural areas from many regions of the nation. Also, the pathogen and parasite load in these bees is being determined. These data are being provided to USDA-APHIS for different bumble bee species to help address health-related concerns. This information is also being shared with the U.S. Fish and Wildlife Service. In the Northwest, the populations of cavity-nesting bees available for bramble-berry pollination have been investigated, along with management of their nesting. The second goal, develop methods to control pathogens and parasites and identify environmental stressors for all bees, progress continued on identifying pathogens in different bee species. For bumble bees and alfalfa leaf cutting bees (ALCB), several infective viruses were identified. In ALCB, progress was made in describing the association of a parasitoid wasp (Mellitobia) with the bees; research is helping to define the species of the wasp, determine its distribution, and how it associates with the bee. We have added to the diagnosis of the parasitoid using x-ray analysis and developing recommendations for its control. Current work is focused on defining unknown pathogens or factors underlying mortality in the embryo and larval stages. The goal is to help growers improve their bee returns and ensure adequate supply of pollinators for the next season to guarantee alfalfa seed production. For honey bees and bumble bees, we are asking how commonly used organosilicone spray adjuvants and pesticides impact the bees. Both species have decreased survivorship when fed organosilicones at low concentration; in honey bee larvae, the adjuvants interact with viral infections to cause significantly greater mortality at the larval/pupal molt. The third goal, understand the foraging and nutritional needs of non-Apis bees, novel methods were used to demonstrate that solitary bees can transmit pollen from one patch of flowers to another remotely located patch, even after depositing pollen in nests. This movement of pollen is important in understanding how to maintain purity in crop seeds and also to understand how to maximize genetic outcrossing in native plant species with restricted populations. Progress has been made understanding the pollen needs of developing larvae for both ground nesting bees and bumble bees. The development of a new pollen trap has facilitated pollen studies in bumble bees. Novel methods for tracking bee movement have been developed in collaboration with ARS colleagues in Maricopa, Arizona. Marker proteins and dyes are facilitating the tracking of bumble bees in green houses and are useful for monitoring movement out of and back into greenhouses. For solitary bees like the Blue Orchard Bee, these dyes persist on the bees and will be used to monitor foraging distance and pollination. Lastly, we have made progress in helping to define pollinator beneficial plants in the western U.S. that can be used in reclamation of natural lands following wildfires. Each of these accomplishments will help to improve the success of bees as pollinators in the agricultural and natural ecosystems. For the last goal (improve bee systematics and taxonomy and our knowledge of bee diversity), we have developed new molecular methods that offer promise in helping to resolve issues associated with bee systematics and at the same time are promising for use in bee identification by non-specialists. Developing these methods is a major achievement. We will be able to create a database with associated molecular identifiers for use by stakeholders. The number of bee records has increased in the U.S. National Pollinating Insect Collection and its associated database, with several new species being described. Some of the new species have unique biology not previously described, like the unique bee making its nests in sandstone in the southwestern U.S. Surveys have been conducted in several areas in the southwest and in western National Parks in collaboration with USGS, FWS, Utah Cooperative Agricultural Pest Survey Program, and NPS. In collaboration with USDA-APHIS and Utah State University, progress is being made on creating a pictorial key for identification of native and potentially invasive Osmia species for use by ports inspectors.
1. Economic model calculates how to use blue orchard bees to increase almond production and profit. ARS researchers in Logan, Utah, and university collaborators, conducted a cost-benefit analysis to assess how using blue orchard bees as pollinators along with honey bees affects profits for almond growers in California. Using ecological data from previous years, the model estimated changes in profits for different management strategies of the two bee species. The model demonstrated that almond yields increased in areas where blue orchard bees were nesting. Adding nest boxes to increase the density of blue orchard bees per orchard area was predicted to have the biggest impact on increased profit for almond production. The findings will support grower decisions in how to use mixed species of managed pollinators to maximize almond yield.
2. Integrated Crop Pollination strategies developed to maximize profits and ensure sustainable pollination. An ARS scientist in Logan, Utah, along with colleagues from university and non-governmental organizations, developed a new method called Integrated Crop Pollination (ICP). ICP uses various strategies to support crop pollination, emphasizing combining tactics that are appropriate for a crop’s dependence on insect-mediated pollination; these include the use of wild and managed bee species and enhancing the farm environment for pollinators through directed habitat management and pesticide stewardship. ICP will allow growers to have flexible options for economically-based decisions via support tools that consider crop value, yield benefit from adoption of ICP components, and cost of the practices. This approach is being transferred to land managers to enable them to decide on the most efficient way to apply ICP to their unique situations to maximize profits.
3. Bumble bee survival negatively impacted by commonly-used organosilicone spray adjuvants (OSS). Concerns are increasing for the health of several bumble bee species found in the United States, with some populations dramatically declining. ARS researchers in Logan, Utah, found that bumble bee adults feeding on sugar water containing organosilicone had decreased survivorship at higher concentrations of organosilicones. The experiments used low concentrations that are predicted to be present in nectar. Organosilicone spray adjuvants currently have no restrictions in use. The use of these adjuvants in tank mixes for pesticide applications in many crops and landscape uses has greatly increased in the last ten years. Finding that OSS negatively impacts adult survival indicates that it may be a factor in bumble bee decline and one that needs to be monitored.
4. Optimization of nesting site distribution maximizes blue orchard bee use. A roadblock to managing a native pollinator for crop production is being overcome. ARS researchers from Logan, Utah, demonstrated a 1.6-fold increase in managed blue orchard bees in a commercial Utah tart-cherry orchard where honey bees were also present as pollinators. Experiments revealed that the number of bees produced and level of pollination was significantly higher when many small nest boxes were distributed across the orchard area as compared to few large nest boxes. This is the first scientific report of successful blue orchard bee reproduction in a conventional tart-cherry orchard and suggests that blue orchard bee pollination of tart cherries can be done sustainably from year to year using in-orchard production of bees.
5. New molecular methods developed to advance the identification of native bees. The use of molecular data in bee systematics is rapidly enhancing the discovery, description, and identification of species important in pollination; but, new methods are needed to improve results, decrease costs, and enable use by non-specialists. One approach is the application of next-generation sequencing combined with targeted enrichment of ultraconserved elements (UCEs). This method has been used to efficiently generate genome-scale datasets for many plants and animals. ARS researchers in Logan, Utah, have adapted the UCE phylogenomic approach to bees and demonstrated that it can resolve challenges in identification of bees, including the agriculturally important mason bees. This method is now being applied to all native bees in North America, and will facilitate native bee surveys.
6. Pollen movement and plant fertilization occurs over a larger distance than previously identified for a native bees. Pollen movement in crop breeding and between separated wild plant populations are important for maintaining purity of crop seeds and enabling healthy wild populations of plants. Bees typically forage locally in a single patch of bloom; consequently, most of the loose pollen that bees move between flowers travels only short distances. However, genetic studies reveal rare but regular long-distance gene dispersal, the result of distant pollen travel. ARS researchers in Logan, Utah, found that pollen remains on the bee’s body and is available for pollination when the bee switches to a new patch of flowers, thus the pollen is carried for longer distances. Pollination of remote plants can occur in some seed crops. Movement of pollen over longer distances should help wild plant populations suffering inbreeding depression.
7. A mechanical trap developed to remove pollen from bumble bee foragers. The characterization of pollen type on foraging bees is important to understand if the bees are foraging on the target crop, or if they are moving off crop to other floral sources. ARS researchers in Logan, Utah, designed, tested and deployed a 3-D printed pollen trap to remove the pollen from the legs of bumble bee foragers returning to a hive. As the first such trap for bumble bees, these are designed to be easily and inexpensively produced and deployed. The devices will provide researchers and producers with an inexpensive and effective methods to collect pollen from bees, allowing for the assessment of the effectiveness of bumble bees on the target crop to which they are deployed.
8. Protein markers and dyes for tracking blue orchard bees are very persistent and allow for bee tracking. Knowing how far bees fly and can pollinate is important for crop success. ARS researchers from Logan, Utah, and Maricopa, Arizona, tested the efficiency of protein markers and fluorescent dyes for the passive marking of adult blue orchard bees. The proteins were detectable using immunoassays and the dyes by visual observation. Both types of markers could be detected for a minimum of 21 days on bees maintained in containers in the laboratory. The technique revealed high persistence of markers and the reliability of this method. Being able to track native bees will give critical information about retention of blue orchard bees in commercial crops and the amount of area they can pollinate.
9. World class bee collection informs agriculture and ecosystem conservation. Essential information on biology, distribution, and seasonality of native bees is needed both for developing managed bees in crop environments and conservation. Institutional collections of bees are invaluable resources for determining the status of the pollinators essential for plant reproduction 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 1.5 million specimens from 136 countries. Data from the collection (including the identity, date and time of collection, host plant, and gender) has been entered into a specimen-level database that now totals 1,476,905 records. This valuable data on pollinators is made available to the public as well as scientists through the Global Biodiversity Information Facility and Discover Life websites.
10. Pollinator plants tested for suitability in U.S. West. Land managers deploying seed mixtures for rehabilitating burned rangelands in the West seek guidance about the bee-friendliness of the different available native wildflower (forb) species. To determine if two commonly planted forbs are attractive to pollinators, blue flax and common yarrow populations were systematically sampled in rangelands for visiting bees, and bee numbers/diversity were compared to samples taken across the Great Basin at 12 other commercially-available native-forb species. Flax and yarrow attracted the fewest and least diverse assemblages of native bees, indicating that neither is bee-friendly. This information has been presented to inform land managers, who have solicited guidance about other plant species for their benefits for native bees and land restoration.
11. A subgroup of mason bees for North America has been defined to aid invasive bee identification. Mason bees (genus Osmia) are a diverse group of pollinators found principally in temperate environments. Most are native but a few are invasive and can be disruptive to agriculture and natural ecosystems. Our ability to recognize mason bees has been hampered by the lack of identification tools. As part of a long-term effort to identify species in this challenging group, ARS researchers in Logan, Utah, examined in detail one subgenus Diceratosmia that resulted in recognition of eleven species, including four new species. These bee species are not only from the United States but also from Mexico, Central America and the Caribbean. Keys and images of diagnostic characters will allow diverse users, from pollination specialists to port inspectors, to accurately identify these mason bees.
Eardley, C., Griswold, T.L. 2017. Taxonomic revision of the Afrotropical species of Pachyanthidium Friese (Hymenoptera: Megachilidae: Anthidiini). Zootaxa. 4237(3):401-453.
Rhoades, P., Griswold, T.L., Ikerd, H.W., Waits, L., Bosque-Perez, N., Eigenbrode, S.D. 2017. The native bee fauna of the Palouse Prairie (Hymenoptera: Apoidea). Journal of Melittology. 66:1-20.
Portman, Z.M., Neff, J.L., Griswold, T.L. 2016. Revision of Perdita subgenus Heteroperdita Timberlake (Hymenoptera: Andrenidae) with descriptions of two ant-like males. Zootaxa. 4214(1):001–097.
Boyle, N.K., Pitts Singer, T. 2017. The effect of nest box distribution on sustainable propagation of Osmia lignaria (Hymenoptera: Megachilidae) in commercial tart cherry orchards. Journal of Insect Science. 17(2):41.
Lundin, O., Ward, K.L., Artz, D.R., Boyle, N.K., Pitts Singer, T., Williams, N.M. 2017. Wildflower plantings do not compete with neighboring almond orchards for pollinator visits. Environmental Entomology. doi:10.1093/ee/nvx052.
Cane, J.H. 2016. Adult pollen diet essential for egg maturation by a solitary osmia bee. Journal of Insect Physiology. 95:105-109.
Cane, J.H. 2016. Specialist bees collect Asteraceae pollen by distinctive abdominal drumming (Osmia) or brushing (Melissodes, Svastra). Arthropod-Plant Interactions. 11:257-261.
Lopez-Uribe, M.M., Cane, J.H., Minckley, R.L., Danforth, B.N. 2016. Crop domestication facilitated rapid geographic expansion of a specialist pollinator, the squash bee Peponapis pruinosa. Proceedings of the Royal Society B. doi: 10.1098/rspb.2016.0443.
Fine, J.D., Cox-Foster, D.L., Mullin, C.A. 2017. An inert pesticide adjuvant synergizes viral pathogenicity and mortality in honey bee larvae. Scientific Reports. doi: 10.1038/srep40499.
Elwell, S.L., Griswold, T.L., Elle, E. 2016. Habitat type plays a greater role than livestock grazing in structuring shrubsteppe plant-pollinator communities. Insect Conservation and Diversity. doi: 10.1007/s10841-016-9884-8.
Portman, Z.M., Griswold, T.L., Pitts, J.P. 2016. Association of the female of Perdita (Xeromacrotera) cephalotes (Cresson), and a replacement name for Perdita bohartorum Parker, 1983 (Hymenoptera: Andrenidae). Zootaxa. 4097:567-574.
Orr, M.C., Griswold, T.L., Pitts, J., Parker, F.D. 2016. A new bee species that excavates sandstone nests. Current Biology. 26(17):792-793.
Gonzalez, V.H., Griswold, T.L., Simoes, M. 2017. On the identity of the adventive species of Eufriesea Cockerell in the USA: systematics and potential distribution of the coerulescens species group (Hymenoptera: Apidae). Journal of Hymenoptera Research. 55:55-102.
Niu, Z., Ascher, J.S., Luo, A., Griswold, T.L., Zhu, C. 2016. Revision of the Anthidiellum Cockerell, 1904 of China (Hymenoptera, Apoidea, Megachilidae, Anthidiini). Zootaxa. 4127:327-344.
Spears, L.R., Looney, C.N., Ikerd, H.W., Koch, J.B., Griswold, T.L., Strange, J.P., Ramirez, R.A. 2016. Pheromone lure and trap color affects bycatch in agricultural landscapes of Utah. Environmental Entomology. 45:1009-1016.
Wilson, J.S., Jahner, J.P., Starley, L., Calvin, C.L., Ikerd, H.W., Griswold, T.L. 2016. Sampling bee communities using pan traps: alternative methods increase sample size. Journal of Insect Conservation. doi:10.1007/s10841-016-9914-6.
Pitts Singer, T., Barbour, J.D. 2016. Effects of residual novaluron on reproduction in alfalfa leafcutting bees, Megachile rotundata F. (Megachilidae). Pest Management Science. doi: 10.1002/ps.4356.
Lozier, J.D., Jackson, J.M., Dillon, M.E., Strange, J.P. 2016. Population genomics of divergence among extreme and intermediate color forms in a polymorphic insect. Ecology and Evolution. 6(4):1075-1091.