Location: Pollinating Insect-Biology, Management, Systematics Research
2020 Annual Report
Objectives
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.
Approach
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.
(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.
Progress Report
This is the final report for bridging Project 2080-21000-017-00D, “Managing and Conserving Diverse Bee Pollinators for Sustainable Crop Production and Wildland Preservation”, which has been replaced by new Project 2080-21000-019, "Sustainable Crop Production and Wildland Preservation through the Management, Systematics, and Conservation of a Diversity of Bees". For additional information, please refence the new project report.
Of the more than 20,000 bee species worldwide, only a small fraction have successfully been managed to pollinate agricultural crops. ARS scientists at Logan, Utah, 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. The project had 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.
Since 2013, ARS scientists in Logan, Utah, have reported research 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, U.S. Forest Service (USFS), Natural Resources Conservation Service (NRCS), U.S. Fish and Wildlife Service (FWS), Bureau of Land Management (BLM), 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 Xerces Society for Invertebrate Conservation, North American Pollinator Protection Campaign, and Saint Louis Zoo. Research has informed regulatory agencies and ag/chem industries on 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. With increased focus on native bees, ARS scientists in Logan, Utah, have actively collaborated in development and design of native bee surveys.
For Objective 1, significant progress was accomplished on using Blue Orchard Bees (BOB) in crop production. In almonds, BOBs, when co-deployed with honey bees, result in an increased fruit set. Economical models were developed, enabling growers to explore inputs into almond systems and economic impacts of adding BOB’s. The management and deployment of BOBs benefited from development of best management practices (BMPs) that maximize pollination and bee reproduction (guaranteeing pollinator availability next season). The BMPs for using BOBs has been transferred to commercial companies and the services of these companies is now in demand by numerous almond growers. This research is now being conducted in other fruit crops like sweet and tart cherries and apples. In cherries in Utah, BOBs have been deployed with honey bees and there has been a sustainable return on bee stocks. No increased yields have been observed, given the high numbers of honey bee colonies and constraints on agronomic inputs like water.
For several crops (almonds and raspberries), ARS scientists in Logan, Utah, have collaborated with university researchers 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 use of wild and managed bee species and enhancing pollinators through directed habitat management and pesticide stewardship. This approach has been transferred to growers to enable them to decide on the most efficient way to apply ICP to maximize profits.
For bumble bee species in the United States, a second survey of populations was made and will contribute to a major database for bumble bee distributions. In addition, pathogen and parasite loads in these species were determined. These data were provided to APHIS and FWS to help address health-related concerns. Production of bumble bees for commercial pollination or for efforts to restore endangered species was supported by finding the best methods to sterilize pollen (bumble bees are fed pollen collected by honey bees that may contain pathogens). Tracking methods for bumble bees were developed and research shows that bumble bees in state-of-the-art greenhouses are able to find escapes, forage out many yards, and return. This is important for understanding potential pathogen spill over and the potential for non-native species to become invasive if overwintering queens are produced.
For Objective 2, progress was made on identifying pathogens in different bee species, using molecular tools. For bumble bees and alfalfa leaf cutting bees (ALCB), RNA viruses, Chalkbrood fungi, nosema parasites, and protozoan parasites were identified. In ALCB, progress was made in describing association of a parasitoid wasp (Mellitobia), defining its species identity, and determining its distribution. New parasites (queen castrating parasitic nematodes) were found in bumble bees that may be important mortality factors in some species.
For honey bees, bumble bees, and solitary bees, impacts of commonly used organosilicone spray (OSS) adjuvants and pesticides were determined. Both honey bees and bumble bees have decreased survivorship when fed organosilicones at low concentration; in honey bee larvae, the adjuvants synergize with viral infections. Fungicides, insecticides, and spray adjuvants were found to disrupt nesting behavior of solitary bees. In addition, the attractiveness of bees to the parasitoid wasp Mellitobia was increased by OSS exposure. This information was shared with grower groups to help develop practices to promote pollinator health and pollination of crops.
Research in support of Objective 3, examined the role of pollen and nectar in bee diets, finding that some solitary bee species require pollen as adults for egg formation. Preliminary data indicate that nectar is essential to solitary bee survival and reproduction, providing critical information on how to support bees when emergence and release are disrupted in managed pollination. Novel methods demonstrated that solitary bees transmit pollen from one patch of flowers to another remotely located patch, even after depositing pollen in nests. This research is important in understanding how to maintain purity in crop seeds and how to maximize genetic outcrossing in native plant species with restricted populations.
Progress has also been made on understanding 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. Bumble bees were found to forage on different floral hosts than honey bees when co-located. For ground nesting bees, such as the alkali bee, data indicates that pollen provisions absorb water and are ingested by larvae, accounting for significant weight gain.
In support of Sub-objective 3.1, novel methods for tracking bee movement have been developed in collaboration with ARS colleagues in Maricopa, Arizona, and can be used over time without killing bees. Marker proteins and dyes, applied either directly to bees or indirectly via sugar solutions, are facilitating tracking of bumble bees in green houses and are useful for monitoring movement out of and back into greenhouses. For solitary bees like Blue Orchard Bees, these dyes do persist on bees and are being used to monitor foraging distance and pollination in commercial orchards.
The impact of wildfires has been determined for some bee populations and their host plants. Ground nesting bees and many native floral hosts that have deep taproots can survive intense fires. Normal cycles of fire may also promote floral resources, creating larger populations of pollinators in natural forest areas. Research has defined pollinator beneficial plants in the western United States for reclamation of natural lands following wildfires.
Research in support Sub-objective 4A included the discovery that the number of specimens in the United States National Pollinating Insect Collection has increased since 2013 from 1.1 million to over 1.7 million and its publicly available database (United States National Pollinating Insect Database) increased from 600,000 records to over 2.1 million records. Several new species have been described and revision of major groups has been made to improve species identifications. Surveys have been conducted in several areas in the southwest and in western National Parks in collaboration with Animal and Plant Health Inspection Service, United States Geological Survey, Bureau of Land Management, Fish and Wildlife Service, Utah Cooperative Agricultural Pest Survey Program, and National Park Service. In collaboration with APHIS and Utah State University, progress is being made on creating an online pictorial key for identification of native and potentially invasive Osmia species (mason bee species not found outside the United States) for use by APHIS inspectors and other regulators. Early detection of an invasive species may allow for its removal before it disrupts the pollination systems required for crops and natural ecosystems. The online key also provides access to other stakeholders for bee information and identification. New molecular methods have been developed that can resolve issues associated with bee systematics (method for classifying the bees and their relationships) and that will be of use in bee identification by non-specialists.
Accomplishments
