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
Pollination is vital to U.S. agriculture and to the maintenance of our wildlands. This project continues to evaluate the diversity and abundance of wild bees in the U.S., and to develop methods for managing bees as pollinators, including developing effective bee production, release, and disease control methods. In 2010, the descriptions of two important groups of pollinators, the mason bees (Osmia) and the carder bees (Anthidiniini) were improved with a revision of the boreal groups of Osmia and the Western Hemisphere Anthidium. The development of an electronic data base of the U.S. National Pollinating Insects Collection advanced in 2010 to include over 840,000 individual specimen records, including when and where each specimen was collected. Research and technology transfer on agricultural pollination methods also progressed. Hands-on workshops and on-farm demonstration projects were conducted to educate farmers on the utility and sustainability of the blue orchard bee for almond pollination in California, completing the second year of a 5-year project with California Cooperative Extension. Research on nesting behavior in solitary bees continued. The gland that produces a chemical marker used by these bees to mark their nests was identified. Research continued toward the development of rearing methods for bumble bees to improve the use of these pollinators in agricultural crops. Effective techniques for nest establishment were developed for four bumble bee species, and experiments were initiated to determine if pathogens affect nest establishment. A 3-year survey of bumble bee populations in the western U.S. was completed and will be used to evaluate the status of declining populations. Research on health issues associated with the alfalfa leafcutting bee continued. Work toward identifying the environmental causes of pollen ball syndrome continued, as did research to optimize the bee release rate for alfalfa seed production and bee production. A two year evaluation of the epidemiology of chalkbrood in alfalfa seed fields was completed this year, and emergence of a second generation of adult bees appears to be a major factor in disease transmission for the alfalfa leafcutting bee. A macro-array analysis was also used to evaluate the effect of temperature on the immune response of this bee. This data will facilitate the identification of key immunity genes. Wild bees are a critical element of wildland restoration and conservation efforts because many native plants require specialized pollination. Research on the pollination biology of plants native to the Great Basin continued, and now several native-plant seed growers are managing solitary bees to boost yields. In addition, wild bee communities in sage-steppe and juniper woodlands have been found to survive wildfires intact (except twig- and wood nesters), as predicted by prior heat tolerance experiments conducted as part of this project.
1. Wild bee survival after rangeland fires. The fates of wild bee communities following wildfire were largely unknown, but critical to anticipating pollination services during large post-fire restoration projects. ARS scientists in Logan, Utah used a new suite of sampling protocols to systematically sample bee floral guilds over time after large burns, sampling from sites inside and outside the burned areas. Plant communities were also characterized. Results show that where rangeland plant communities were in good shape before burning, their diverse native bee communities returned the following years, and the native wildflowers likewise recovered. This work was important for recommending that initial seeding in restoration projects should include plants that are broadly attractive to local native bees to sustain these bees until the native plant communities can re-establish, since that re-establishment can take several years.
2. Western bumble bee population range documented. Beginning a decade ago, populations of the Western bumble bee, Bombus occidentalis, began to rapidly decline in the western U.S. prompting concerns that environmental problems may be imperiling all North American bumble bees. ARS scientists in Logan, Utah with a database of 73,759 bumble bee specimens from 47 natural history collections throughout the U.S. were developed and used to establish and map the historic range of this species. This year, ARS scientists also completed a three year survey of bumble bee abundance, sampling over 100 sites in 10 western states. The current survey data is being used to predict the decline in abundance and range of this species relative to other bumble bees. This work will be useful for conservation policy, including seeking an Interational Union for the Conservation of Nature (IUCN) Red List Status for this species.
3. Nesting methods successfully established for four bumble bee species. Bumble bees are important pollinators of commercial greenhouse crops, but are difficult to raise in captivity. Because it is particularly difficult to get queens to establish new nests in captivity, ARS scientists in Logan, Utah, tested three nest establishment methods on four species of bumble bees. Their results show that some techniques greatly increased the success rate (by four-fold) in some species, in comparison to other techniques. By targeting the proper rearing techniques to a given species, producers and researchers will be able to save time and resources when producing bumble bees in culture.
4. A gland associated with the sting appartus likely aids bees in marking their nests so they can find their way home. Blue orchard bees and alfalfa leafcutting bees are solitary bees that must be able to distinguish their nests from thousands of others in crowded nesting sites, and chemical markers are used as nest recognition cues by these insects. Using high-powered microscopy to examine the Dufour’s gland and sting apparatus of these two bees, ARS scientists in Logan, Utah, and collaborators discovered that, unlike honey bees and bumble bees, the gland of these solitary bees enters into the base of the sting rather than ending before the sting base. The structure and arrangement of the Dufour’s gland along with nest-marking behavior of these bees support the idea that the gland is the likely source of an individual nest recognition cue. Understanding the chemical signals used by cavity-nesting bees during nesting can be used to improve efforts to get the bees to nest where needed, thwart practices that disrupt the bee’s natural nesting, and provide a means to develop natural or synthetic nesting attractants.
5. Nest attraction cues found for solitary bees. An ARS scientist in Logan, Utah, and collaborator found that alfalfa leafcutting bees, Megachile rotundata, will start nests in artificial nesting boards if these contain old nest cells belonging to their own species, and even those of another species, but are much less likely to nest where no old nests are found. They also discovered that nesting preference depends on which components of old nests are present; that bees will avoid the nest cavities that have pieces of old nest walls, as these bear unique odors of the bee that had nested there in the previous year; and that bees prefer cavities that have old cocoons or fecal droppings. Understanding the odor cues that mediate nesting behaviors of cavity-nesting bees is important for developing nest attractants that keep bees at commercial nesting sites to enhance pollination of nearby crops.
6. Ozone fumigation as a disinfectant for bee nesting materials. It was previously shown that ozone can break down pesticides and kill insect pests when used at very high concentrations (920 milligrams ozone/cubic meter). This year, an ARS scientist at Logan, Utah, found that high levels of ozone can be used to kill chalkbrood and foulbrood spores; these are disease contaminants in honey bee comb. However, ozone was only effective against foulbrood spores when used at 8,560 milligrams ozone/cubic meter for 3 days in combination with high temperature (122F) and high humidity. These results were important for showing that ozone is a potential fumigant to decontaminate honey bee supers, honey comb, and alfalfa leafcutting bee nesting boards, but it cannot be used on the bees themselves, and beekeepers may not be able to realistically achieve the conditions necessary to kill all diseases.
7. New species of mason bees found in North America. The identities of a group of mason bees that are informally called the "black" Osmia is complicated. ARS scientists in Logan, Utah, completed a taxonomic revision of this group, a task that required careful study of a number of type specimens from Eurasian. The result was the identification, by these ARS scientists, of two species in North America previously known only from Eurasia, and the discovery of two more completely new species, not known to occur elsewhere. This research effort led to the development of taxonomic keys, data on genographic distributions, and images of diagnostic characters, developed for use by other bee researchers to aid in the identification of North American black Osmia.
Tanner, D.A., Griswold, T.L., Pitts, J.P. 2009. A Revision of Dianthidium Subgenus Mecanthidium Michener (Hymenoptera: Megachilidae). Journal of Hymenoptera Research. 18(2)183-191.