Globally, about one-third of domesticated crop production and about 70% of all plant species require pollination services by bees, birds, butterflies, bats, beetles and other insects.
Pollinator Research Highlights at Eastern Ecological Science Center
June 20-26, 2022 is Pollinator Week, an annual event recognizing pollinator health. Animal pollinators are critical for sustaining healthy ecosystems and prosperous human populations. Here are a few highlights of pollinator research conducted by U.S. Geological Survey’s (USGS) scientists at Eastern Ecological Science Center.
Native Bee Inventory and Monitoring Laboratory
The Native Bee Inventory and Monitoring Laboratory is a collaboration between USGS and U.S. Fish and Wildlife Service (USFWS), and is part of Eastern Ecological Science Center’s campus on the Patuxent Research Refuge. The lab is the primary support institution for monitoring, identification, and survey techniques for the 4,000 North American native bee species. Building on a foundation of nearly 20 years of dedicated work on native bees, the lab is now rapidly expanding due to the growing recognition of the importance of native bees and other pollinators for healthy ecosystems.
The Native Bee Inventory and Monitoring Laboratory has supported and consulted in every state, and collaborated with hundreds of students, academics, institutions and non-governmental organization around the globe. In order to increase the capacity for expertise in natural history, monitoring and identification for native bees and stinging wasps (such as hornets), the lab has developed technique manuals, training classes, and identification guides for over 1500 species. The lab also maintains an online gallery of high-resolution public domain images of bees and to aid in identification and consults and trains numerous people interested in the tricky art of processing and identifying bees.
The Native Bee Inventory and Monitoring Laboratory is now increasing work on understanding the complexity of bee-plant interactions and has documented at least 200 species of bees visiting plants on Patuxent Research Refuge so far. Plants have different seasonal and daily bloom times, chemical compositions, colors, and shapes to attract only certain kinds of bees, and bees are equally picky about which plants they visit. The close relationship between bees and plants helps ensure that bees move pollen from one flower to another flower of the same species, which is often necessary for plants to reproduce and create seeds.
To support research into bee-plant interactions, an area of the refuge previously used for raising endangered cranes has recently been outfitted with automatic watering systems. Irrigation, the lack of deer and ample space for growing out native plants has led to refuge staff, other USFWS groups, and community non-profits working on native pollinator plantings to volunteer to help raise these plants, some of which are then used in partner efforts to recover landscapes for pollinators and create biodiverse habitats.
Improving pollinator forage on U.S. Department of Agriculture conservation lands
U.S. agriculture productivity relies heavily on both domesticated and native insects for pollination services, and the economic value of insect pollination services is estimated at approximately $15-30 (USD) billion annually. Reliance on domesticated insects such as European honeybees (Apis mellifera) for pollination services is growing even as colony numbers decline.
Since 1985, programs administered by the Farm Service Agency and the Natural Resource Conservation Service have restored many millions of acres of grassland, providing important mixed forbs (flowering plants) that honeybees use for forage. However, escalating values of agricultural crops, especially those for bio-energy, have reduced the willingness of landowners to enroll or re-enroll in conservation programs such as the Conservation Reserve Program and Environmental Quality Incentives Program. As conservation acreage area has declined, there has been an increasing need to improve the habitat for honeybees and other pollinators on federal conservation program lands.
Since 2014, researchers at the USGS Eastern Ecological Science Center in collaboration with USGS Fort Collins Science Center, USGS Northern Prairie Wildlife Research Center and the U.S. Department of Agriculture have led genetic sequencing and bioinformatics efforts to identify the specific plants honeybees are visiting. Researchers use genetic sequencing of samples of pollen collected by honeybees to determine which plant species the bees have visited and the relative proportion of different plants within the pollen pool.
This research provides information on which flowers are used and their proportion in the bees’ diet. Results will inform the development of cost-effective seed mixes that can be used to enhance honey production and improve the health and fitness of honeybee colonies on U.S. Department of Agriculture program lands.
Identifying pollinator communities using environmental DNA from flowers
When a pollinator such as a bee visits a flower, it may leave evidence of the visit behind in the form of environmental DNA, or eDNA. As living or dead organisms interact with their environment, they release eDNA through shed skin or hair, excretions like saliva, or even body parts. Sampling the environment for eDNA and sequencing it can help researchers determine what organisms have used that area without having to observe the organisms themselves. If researchers are able to use eDNA from flowers to tell which pollinators have visited recently, they may be able to use this new method to measure pollinator biodiversity instead of traditional monitoring methods like bee bowl traps or visual observations.
However, trying to detect pollinators by using eDNA extracted from flowers is a new approach, and many aspects of how to properly survey for and process samples are poorly understood and untested. For example, how often do bees and other pollinators leave behind detectable eDNA after a flower visit? Do different methods for extracting eDNA from flowers influence the ability to detect which pollinators have visited?
In May 2022, scientists at Eastern Ecological Science Center initiated a collaborative project with six other USGS science centers to investigate the use of pollinator eDNA left on flowers. This research is part of a larger effort funded by the Bipartisan Infrastructure Law to assess ecological resilience of restored grasslands. The first phase of the project will sample over 1500 flowers from eight states in grasslands that have and have not been restored. The results of this study will help researchers better understand which plants best support pollinators and provide information to managers on which native seeds to use for restoration efforts. This study will also build a foundation of information about pollinator diversity in America’s grasslands.
Determining the influence of ozone pollution on pollination
Ozone pollution results from the use of fossil fuels like gasoline, jet fuel, and diesel oil. Winds carry ozone across the landscape, polluting the air of urban, rural, and natural areas, across the nation and around the globe. Several negative effects of ozone on the environment have been documented, such as changes to water and nutrient cycles and adverse effects on plant and human heath, but to date, no field studies have been conducted to determine if ambient atmospheric ozone also disrupts pollination.
Recent laboratory research suggests that ozone may break down the chemicals (scent) that flowers release into the air to attract pollinating insects. A floral scent may be composed of over 100 organic volatile chemicals. Bees follow the trail of these floral volatiles to locate distant flowers, and disruption of these flower-visitor signals could threaten habitat quality, biodiversity, and even national security by disrupting the U.S. food supply system.
Scientists at Eastern Ecological Science Center have partnered with University of California and U.S. Department of Agriculture to explore relationships among bee foraging success, weather, and ozone concentrations. Ultimately, this research will be used to better understand effects of fossil fuel use on pollination and to inform air quality regulations.
To learn more about Eastern Ecological Science Center’s research on pollinators, and other fish and wildlife, visit usgs.gov/centers/eesc. Follow us on Facebook at facebook.com/USGSEESC for the latest updates on our science and ways you can get involved, including events at our campuses.
A version of this article appeared in the Friends of Patuxent Spring 2022 Newsletter.