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 (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.
Pollinating Insects—Biology, Management and Systematics 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 2014, ARS PIBMSRU scientists reported on solitary bees and bumble bees in ways that are relevant to stakeholders that include the almond and alfalfa industries, the U.S. Forest Service, the Fish and Wildlife Service, the Bureau of Land Management and the Natural Resources Conservation Service, as well as any U.S. citizen concerned with bee health and conservation. Bee pollination is critical for the production of nuts, fruits, and vegetables that offer diet richness in nutrition and taste for humans and livestock. Whether in the ARS facility, in public lands, or on private agricultural farms, PIBMSRU scientists continue to progress in their efforts to discover and provide bee pollinators other than honey bees. After several years of collaborative research, a patent application has been filed for a blue orchard bee (Osmia lignaria) nesting attractant and progress is being made to find a method of delivery and commercial distribution. This product will lure female bees that are tree fruit pollinators to artificial nest sites due to odors resembling those of previously used nests. In addition, research was also performed to show how use of blue orchard bees along with honey bees for almond pollination improves almond yield, especially near to where the orchard bees make nests. Such research is helping to develop the best management practices for the use of a solitary bee for pollinating a crop (almonds) that demands approximately 1.6 million honey bee hives for its nearly 800,000 acres of California almonds annually. Having a complimentary pollinator to honey bees helps the almond industry to reduce the demand on honey bees and the consequential stress on so many honey bee colonies due to transporting them to California in early spring when natural food resources are scarce. Research continues also for improving the management of alfalfa leafcutting bees (Megachile rotundata) by monitoring bee offspring through summer development and knowing under what conditions those bees develop due to where their mothers build nests in field domiciles with different arrangements of nesting materials. Furthermore, alfalfa leafcutting bee adults are being exposed to different light regimens in incubators to determine how day-length may also affect the outcome of offspring development and explain differences seen in the development of bees reared in different latitudes, such as between bees reared in Canada versus bees reared in California. Bees forage for nesting resources over seasons that are 6 to 24 weeks, depending on their life cycle and whether they are solitary or social. Although many local flowers may offer rewards for bees, not all of them can or will be used by the bees. Some reasons for this selectivity may be that they prefer only certain flowers (an inherited preference), they cannot access the rewards due to flower structure, or they are out-competed by other pollinators. Social bees, such as bumble bees and honey bees, have long foraging seasons and, therefore, have many opportunities for worker bees to find and use various resources as flowers become available over time. A new ARS study is underway to obtain the samples of the pollen collected by bumble and honey bees over an entire season to learn more about their use of the landscape and how resources from that landscape may affect colony quality and reproductive success. Also, the use of CRP lands for increasing populations of alfalfa leafcutting bees is being evaluated in southern Idaho by ARS scientists, and, thus, may reveal that natural landscapes provide a variety of resources important to bee health that agricultural landscapes lack. Such resources might include ample flowers for finding protein for consumption by adult female bees at the end of the day, which an ARS scientist is finding to be necessary for maturation of eggs for laying on the subsequent day. Landscapes also change due to land use practices or wildfire, and such changes can affect bee diversity or the availability of nesting resources. ARS scientists are learning that after fire and a grazing hiatus, a decade of rotational grazing does not seem to diminish pasture quality or wildflower abundance and diversity overall. Another study is revealing that sage-steppe fire leaves the ground-nesting bee community intact and active in the weeks following a burn event. On a larger scale, ARS researchers are using models to qualify landscapes regarded suitable for agriculturally important bees, such as bumble bees, and, therefore, the possible ranges of certain species of bees can be predicted and their presence or absence used to understand pollinator abundance or decline. If landscapes are altered by human practices or fires, it is important to understand all of the potential impacts on the ecosystem and its local flora and fauna. Economic and cultural influences are also bound to affect aspects of the pollination industry. To gain a better understanding of influences on pollinator affordability and trends over time, computer modeling is being employed to look for the effect of the price of honey and pollination fees on the number of honey bee colonies from 1962-2013 in the United States and Canada. Results from the model are showing that the effects of fluctuations in honey prices and pollination fees by each country and individual states in the early years were correlated with local economic patterns, but more recently are showing correlation with U.S. national honey price trends. In California, where pollination fees are known and increasing, those fees are more correlated with colony trends than honey prices. Other modeling currently underway is looking for temporal changes in crop diversity patterns and its effect on honey bees. Models that define complex relationships between agriculture, economics, and the environment can help to prioritize and strategize future focal research areas that may more effectively solve problems with honey bee and other pollinator shortages. The archiving of bee specimens and data is extremely important for preserving the baseline data on a changing planet. Access to databases of museum bee collections allows for examination of specimens for comparative studies, knowledge of where bees have been collected in the past and present, upon what floral resources they were collected, and how diverse locations are in their bee fauna. ARS scientists 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 individual specimens in The National Pollinating Insects Collection now includes all the collection data for 1.1 million pinned bees. This georeferenced data allows ARS scientists to identify spatial and temporal gaps in our knowledge of the pollinator fauna and, thus, to target these gaps for data collection. Ongoing revisionary studies of the mason bees (Osmia), a group already known to include manageable crop pollinators, will enhance our ability to identify and develop additional pollination options. A collaborative study of the relationships among carder and resin bees (tribe Anthidiini) using a combination of structural and molecular data is in final stages. The resulting tree of life will provide valuable information on the evolution of bee nesting traits and physical characteristics. Collaborations with U.S. National Wildlife Refuges in western United States is documenting the rich diversity of bees on refuges and providing baseline data for future assessments to determine whether bees are in decline.
1. Bee nest attractant was developed for orchard pollinator. ARS researchers in Logan, UT and collaborators from ARS in Fargo, ND and a CA pollination company filed a U.S. Patent Application for “Bee Attractants” after identifying chemicals that were demonstrated through laboratory and field trials to attract blue orchard bees (Osmia lignaria) to artificial nesting materials, which leads to better nest establishment and improved management by retaining populations of this important tree fruit pollinator. Blue orchard bees are proving to be very efficient almond pollinators, especially when used concurrently with honey bees.
2. Fungicides used to protect almonds and other orchard crops affect the nesting behavior of two species of solitary bees. ARS scientists in Logan, UT performed tests on the blue orchard bee (Osmia lignaria), used for CA almond pollination, and the alfalfa leafcutting bee (Megachile rotundata), used for alfalfa pollination, that nested in artificial cavities provided along with flowers in large field cages. The effect of nighttime sprays of two common fungicides onto the caged flowers was seen the next day and beyond when female bees were confused about the location of their own nests, thus revealing a disruption of nest recognition ability. If the bees were not caged, they likely would have abandoned the nesting site, as has been observed by orchard bee managers using these bees for almond and cherry pollination. The effects of fungicides will have to be mitigated, or fungicides will have to be found that do not produce these symptoms, in order to successfully use these pollinators in conventional crop operations.
3. Larger tomatoes are grown in greenhouses when pollinated by bumble bees. Commercialization of western native bumble bees is progressing, and the feasibility of using these species to pollinate tomatoes is not fully understood. ARS scientists in Logan, UT studied the ability of different bumble bee species to pollinate tomatoes in greenhouses and discovered that three bumble bee species are all equally effective for the task. Tomato plants pollinated by bumble bees all set significantly more and larger fruit than control plants, which did not receive bumble bee pollination. This information will allow bumble bee producers to focus efforts on these effective pollinators and will inform tomato producers when choosing pollinators to buy.
4. Genetics of economically important pollinators provides information for better management and treatment of diseases. The Hunt bumble bee is an emerging managed pollinator, which is being developed for greenhouse pollination. ARS scientists and university scientists in Logan, UT, sequenced the transcriptome of this bee and conducted a comparison of the genes expressed for immune response in this species with other insects. This work lays the foundation for studies of the disease susceptibility in the future and aids in our understanding of immune response pathways in bees.
5. Management is required for survival of bees sourced from one region to pollinate orchards in another region. ARS scientists in Logan, UT tracked the development and survival of blue orchard bee (Osmia lignaria) offspring that were descended from populations from California, Washington, and Utah, and were then reared together under a temperature regime simulating those of a California almond-growing region. Scientists found that Washington and Utah offspring developed similarly. However, California offspring developed slower, were more metabolically active, and survived better under California conditions than did populations native to regions at higher latitudes. Regardless of geographic origin, cocooned adults managed under prescribed thermal regimes emerged faster and lived longer after wintering. This study strongly supports the need for prescribed management of blue orchard bees for providing this pollinator for services outside of its place of origin and the potential risks of careless movement and mixing of these bees around the United States.
6. Grazing does not reduce quality of landscape for bees. ARS scientists in Logan, UT found that two decades of rotational cattle grazing on 30,000 acres of sage-steppe did not diminish wildflower abundance or diversity for wild bees, but did shift cover to more grass and less shrubs and bare ground compared to continuous grazing. Such findings help to guide land managers in decision-making for conservation of all wildlife, including bees, while managing livestock on public and private lands.
7. Largest collection of bees in the world is housed at ARS Logan, UT. 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, UT, one of the largest collections of bees in the world, containing approximately 1.3 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, and gender, has been entered into a specimen-level relational database for 1,066,677 of the specimens in the collection. This valuable data on pollinators is made available to the public as well as the scientific community via the larger, cooperative research tools of the Global Biodiversity Information Facility and DiscoverLife websites.
8. Revision of carder bees for the Western Hemisphere provides new identification tools. Carder bees (Anthidium) are a diverse group of pollinators found equally in temperate and tropical environments; most are native, but some are invasive. The ability to recognize carder bees has been hampered by the lack of identification tools. ARS researchers in Logan, UT conducted revisionary work that resulted in recognition of 92 species including 21 species new to science and two invasive species. Keys and images of diagnostic characters allow pollination specialists to accurately identify carder bees. A subsequent data publication provides land managers and researchers with the complete set of 22,648 specimen records including georefenced location, date, and flowering plant association, made available on the web.
9. Female solitary bees must eat pollen to produce mature eggs. Although known for honey bees, for solitary bees, no previous study has systematically evaluated or experimentally manipulated pollen feeding. ARS researcher in Logan, UT and a WA university collaborator found that females of the alkali bee, Nomia melanderi- a native, alfalfa pollinator- feed themselves pollen at the end of each day, after earlier collections of nectar and pollen for making a provision mass for each offspring. A follow-up study with a different solitary bee, Osmia montana, exemplified a consequence of missing the pollen meal. Female bees caged with pollen-less sunflowers failed to mature their first egg, whereas those with pollen-providing sunflowers were able to produce mature eggs and continue to nest. Overstocking bees in commercial production situations may limit the pollen available for adult bee consumption late in the day, leading to suboptimal production of pollinators for use in a subsequent year.
10. Bumble bees extend into never-before reported ranges of a national park. Bumble bees are important pollinators of native plants, especially in alpine environments. Working with seven National Parks in the Pacific Northwest, ARS scientists surveyed the bumble bees of these parks in coastal areas and alpine meadows, describing the habitat ranges and genetic diversity of species found in each park. In Olympic National Park, two species of bumble bees were found in remote areas that had never been recorded in the park before, and a rare species of bumble bee was also recorded despite recent declines in other regions. Park managers can now use this information to plan resource allocation to preserve bumble bee communities in the face of global climate change.
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