In 2019 Jennifer Ison tracked and sampled ground nesting bees in Exp. Plot 2 with Miyauna Incarnato, Avery Pearson and Ren Johnson from the College of Wooster. Bees were captured, refrigerated, fluorescent dyed, released and tracked to their nests. Several bee nests were located and shot with GPS Darwin. One was excavated and brought back to Wooster for study.
Job BEENESTS_20190730_DARW contains 13 points shot of nests and their surrounding plants. The job is backed up in three locations:
The tallgrass prairie once occupied vast expanses of land across America’s heartland. Today, it is among the most threatened and least protected habitats in the world. Each year, parts of the tallgrass prairie continue to be lost to agriculture and development making the conservation and protection of this system of utmost importance.
Native bees are the most abundant and most important pollinators in the tallgrass prairie. The bees that we study for this project are called solitary bees. They are different from honeybees in that they are native to North America. They are also different from bumblebees (where many genera are native to North America) in that they do not form a colony and build their nests individually.
We know a lot about the kinds of things bees like to eat (pollen and nectar) and their foraging behavior. However, most solitary bees spend the majority of their life in their nests, yet we know so little about what conditions are suitable for them to build their nests. In the tallgrass prairie, over 80% of bees are solitary, ground-nesting bees. We have a lot to learn about the kinds of habitat suitable for them to build their nests in.
We know some things about what ground-nesting bees may like. Evidence suggests they might like sandy soil, bare ground, and well-drained, south-facing slopes. However, we don’t know what bees in the tallgrass prairie may like for their nesting habitat conditions as most of these studies have been done across other ecosystems.
Much of the prairie has been changed from its original condition. We call the history of this condition “land-use history.” I am interested in how the history of the land may determine where bees build their nests in the ground. Some common types of land use history are remnant prairies which are pristine habitats with untilled soil, prairie restorations which are plantings of prairie plants with disturbed soil, and old fields which are fields leftover from agriculture that may have been tilled or grazed.
Using emergence traps, we moved traps everyday for a total of 1,440 across the season. We caught 110 ground-nesting bees in traps across 24 sites this summer. I placed traps at 8 different locations, each with three different land types at each location (remnant prairie, prairie restoration, and old fields). We found that the most bees nest in the prairie (40), while restorations and old fields have the same numbers of nesters (35). While land use is not good at determining bee nests, we did find that the location and land use when combined are both important in determining where bees nests.
I also placed pan traps at all 24 sites and caught 564 bees. Pan traps were colored blue, white, and yellow to attract a diversity of foraging bees at every site. We will use these bees to compare the foraging and nesting communities at each site.
I also measured many microhabitat characteristics of the soil and vegetation at some of the traps. We found that bare ground is a good predictor of where bees build their nests. We also found that the soil texture, especially the amount of silt and sand help determine where bees nest. A diverse plant community with lots of native plants is also a good predictor for bee nests.
We still have a lot more work to do to determine where bees are building their nests. Our next steps are to identify all the bee specimens caught in ground nests and in pan traps. Once specimens are identified, we can learn more about the species specific results for ground nesting bees.
Two of the tents used to capture bees out in the field
Start year: 2018
Location: Hegg Lake Wildlife Management Area restoration, Riley, Aanenson, East Elk Lake Road, and other non-project sites
Physical specimens: 674 bees were brought back to CGB and are currently being pinned and photographed by Mike Humphrey. Soil samples were collected from every location where bees were caught + a random sample from other traps.
GPS points shot: We shot points for all trap locations. Ask/email Kristen for this data.
Products: This work is part of Kristen’s Master’s thesis
Previous team members who have worked on this project include: Anna Vold (2018)
Thanks so much to help from Team Echinacea 2018, especially Anna Vold who helped measure soil texture. Also many thanks to Emily Staufer from Lake Forest College who processed bees from HFW, and Mike Humphrey who has pinned some bees from this project.
During the summer of 2024, Team Echinacea completed the second year of its ENRTF funded project to better understand how prescribed fire influences ground nesting bee habitat, food resources, and diversity. Understanding the associations between land management methods and ground nesting bees is essential for providing reccomendations to policymakers and practitioners interested in native bee conservation.
We surveyed solitary bee diversity and nesting habitat before and after prescribed fires in a subset of 30 prairie remnants and 15 prairie restorations to determine how prescribed fire affects solitary bee nesting habitat and abundance. We used emergence traps to sample the community of solitary ground nesting bees. This was complemented by detailed measures of soil and litter to characterize how prescribed burning influences the nesting habitat (read more here).
2024 REU student Zach Zarling deploys an emergence trap at a site near Hoffman, Minnesota
We deployed emergence traps at our random “burn and bee points”(BBPTs) in prairie remnants and restorations from early June to mid September. Our deployments spanned three rotations (4-6) of BBPTs and we put out a total of ~1,159 emergence traps. On reccomendation from Dr. Alex Harmon-Threatt, we also performed 10 minute “pollard walks” on deployment to estimate the number of foraging bees at each site. These foraging numbers will be compared to nesting incidence as part of Ian Roberts’ thesis project.
As of December 21st, specimens caught in this year’s deployments have been pinned, labeled, and transported from Chicago Botanic Garden to the University of Minnesota, where Zach Portman, a bee taxonomist, will identify them. Team Echinacea also collected lots of non-bee bycatch while processing specimens collected in the traps: including millipedes, flies, and even a prairie skink! To avoid wasting these specimens, we plan to categorize this bycatch into broad taxonomic groups (like Dipterans, Orthopterans, etc) and examine potential associations between our experimental treatments and general arthropod diversity across our study sites.
Pinned specimen from 2024’s emergence trapping, likely an Agapostemon virescens.
While working on pinning and processing specimens, Ian Roberts produced a poster containing analyses from the 2023 emergence trapping data to present at Entomology 2024. The poster can be viewed here. Future data analyses will feature data from both sampling years, as well as microhabitat measurments and and diversity indices.
Start year: 2023
Location: prairie remnants and restorations in Solem Township, MN.
Data collected: insect samples, counts of foraging bees
Samples or specimens collected: Pinned bees are currently being identified at University of Minnesota. Bycatch is in the freezer at Chicago Botanic Garden.
Products: poster presented at Entomology 2024 (see above for link)
During the summer of 2023, Team Echinacea embarked on an ENRTF funded mission to better understand how prescribed fires influences solitary bee nesting habitat, food resources, and diversity is critical for providing recommendations about how prescribed fire should be used to promote pollinator conservation and healthy prairie.
We surveyed solitary bee diversity and nesting habitat before and after prescribed fires in a subset of 30 prairie remnants and 15 prairie restorations to determine how prescribed fire affects solitary bee nesting habitat and abundance. We used emergence traps to investigate composition of solitary bees in prairies. This was complemented by detailed measures of soil and litter to characterize how prescribed burning influences the nesting habitat (read more here).
We deployed emergence traps at our random points (bb points) in prairie remnants and restorations in mid-June – early September. Our deployment spanned three rotations of bb points and we put out a total of ~1,238 emergence traps.
El, Luke, and Jan, 2023 pollinator crew, deploy an emergence trap at a bb point.
As of September 28, members of Team Echinacea had processed 850 vials, 122 of which contained bees. Our preliminary catch rate is 14%! These specimens were pinned and are currently at Chicago Botanic Garden, awaiting transportation to University of Minnesota where Zach Portman, a bee taxonomist, will identify them. Team Echinacea also collected lots of non-bee bycatch while processing specimens collected in the traps. Bycatch is currently stored in our freezer at Chicago Botanic Garden.
Jan pins a bee that they found while processing vials from emergence trapping!
Ian Roberts, a M.S. student with the Echinacea Project, has taken charge of the Emergence trapping project and is currently coordinating data entry. When emergence trapping resumes in the 2024 field season, we will be well set up, thanks to detailed written and videotaped protocols made by our summer 2023 pollinator team. The prtocol can be found here: “~/Dropbox/enrtf/emergenceTrapping2023/Emergence Trap Protocol.pdf”. Video instructions are located in “~/Dropbox/enrtf/emergenceTrapping2023/exampleVideos”.
Start year: 2023
Location: prairie remnants and restorations in Solem Township, MN.
The Echinacea Project has been investigating tallgrass prairie in Douglas and Grant Counties, MN since 1995. Our research on native plants & pollinators identifies threats to prairies as well as conservation opportunities. For example, in a 21-year investigation of purple coneflower (Echinacea angustifolia) we found that prescribed burns improved seed production by synchronizing reproduction and improving pollination. We recently submitted a proposal to the Legislative-Citizen Commission on Minnesota Resources for funding to build on our long-term investigations. We propose research projects to investigate how prescribed burns affect solitary, ground-nesting bees — the most important pollinators in tallgrass prairie. Specifically, we will examine how burns affect solitary bee diversity, nesting habitat, and food resources (e.g. quantity and nutritional quality of pollen and nectar). This research will produce valuable information for natural resource managers, including guidelines for how to maintain insect pollinators and prairie plants with prescribed fires.
Augochlorella striata (aurata), photographed by Gretel Kiefer.
This is a guide to the bees that visit Echinacea at our study site in Minnesota during the summer field season. The Echinacea Project has collected over 900 specimens and 43 species of native bees. Each page of this guide includes a description of a native bee taxon to be used for quick identification (as well as the link to DiscoverLife to be used as a tool in more accurate identification) and life history traits such as nesting and foraging habits. Also included are the common name of a genus, the number of species and specimens The Echinacea Project possesses of these genera and species, and pictures and videos from the Echinacea Project Youtube of the bees collecting pollen on Echinacea in the field. The pages are organized by both family and genus, and information on individual species within a genus are included where we have that information.
These solitary, generalist bees show great variation in both their physical traits and their life history characteristics. They range in size from 3 mm to over 20 mm long. In shape, bees like the small, black, ant-like Lasioglossum can appear completely unrelated to the larger more hairy Halictus, though they are both part of the Sweat Bee family, Halictidae. (Mader et al. 230, 237)
Furthermore, each genus nests and forages differently, from solitary to semi-social to communal, from digging their own nests in the soil to nesting in existing holes in wood or plant stems. Variation among nesting patterns can even be seen within genera. A solitary bee constructs a nest of her own or uses a nest in an existing crevice and forages solely for herself and her brood. (Mader et al. 27) Unlike solitary bees, groups of eusocial bees contain certain caste roles, in which each individual has his or her own job to help the group survive. In native bees, this is generally seen among a series of generations of one lineage, in which the founding bee serves as the queen, her offspring serve as the female workers, and the male drones wait to mate with the new queens in the fall. Communal bees nest together, but generally show solitary behavior, a single member providing only for her own brood. However, cooperation among communal bees has been studied, such as working together to build the nest and certain bees serving as guards at the entrance. (Mader et al. 35-45)
Andrena, photographed by Gretel Kiefer.
In contrast to solitary bees, social bees such as honeybees and bumblebees are attracted to the nectar stores of native plants, which they use to create energy-rich honey for their offspring. Social bees are not visitors to Echinacea on our study site, perhaps because they are less likely to visit plants with less bountiful nectar, such as Echinacea. Solitary bees do not produce honey and are attracted to a wide variety of plants for their pollen, which they bring back to their nests to feed their larvae.
Foraging habits are more or less consistent among the collected native bee specimens. The vast majority are generalists, meaning they visit many species of flowering plants, imposed by their tongue length and size (Mader et al. 32).
The Echinacea Project has conducted several studies on pollinators, including one published in 2010, under the direction of Stuart Wagenius and Stephanie Pimm Lyon, which studied pollen limitation vs. pollinator limitation in Echinacea. Results showed that, in both years of the study, bee visitation actually increased with isolation of individual plants and did not vary significantly with population size. As expected, plant isolation increased pollen limitation and lowered seed set. This means that pollen receipt limits reproduction in Echinacea but pollinator visitation does not. The hypothesized causes of pollen limitation that are consistent with these surprising results include: incompatibility, pollen quantity, the identity and density of local co-flowering plants, and the synchrony of flowering. (Wagenius and Pimm)
Mader et al. Attracting Native Pollinators: Protecting North America’s Bees andButterflies. 2011. The Xerces Society.
Wagenius, Stuart and Pimm Lyon, Stephanie. “Reproduction of Echinacea angustifolia in fragmented prairie is pollen-limited but not pollinator-limited”. Ecology, 91(3), 2010, pp. 733–742. 2010. The Ecology Society of America.
Melissodes, photographed by Gretel Kiefer
Andrena, photographed by Gretel Kiefer
Megachile, photographed by Gretel Kiefer
Augochlorella aurata, photographed by Gretel Kiefer
During summer 2024, Team Echinacea continued to collect data on local environmental conditions in order to understand which environmental factors are associated with good habitat for ground-nesting bees. These data complement emergence trapping for our ENRTF funded research on fire’s influence on ground nesting bees habitats. We sampled local environmental conditions near randomly placed “burn and bee points” (BBPTs) in prairie remnants and restorations.
A deployed emergence trap next to a set of marking flags. Microhabitat data was sampled within a meter of these marking flags.
Unlike the 2023 season, we did not collect data on light levels at BBPTs this year. Instead, we measured soil temperature just under the surface using a digital thermometer, along with soil compaction via a penetrometer and litter depth via a meter stick.
Team Echinacea conducted microhabitat assessments for remnant prairies at rotation 4 BBPTs. Over the summer, we took microhabitat assessment measurements at a total of 241 measurments.
Start year: 2024
Location: prairie remnants and restorations in Solem Township, MN
Today we welcomed goats to Hjelm. They are already hard at work eating their way through the foliage. Keep up the good work, goats! Most of the humans worked on finishing searching for Stipa in p01 and started planting a new production garden to generate seed to add to the experimental plots. Ian and Liam valiantly continued staking points for the pollinator emergence study. Wyatt and Abby are getting ready to begin a study investigating the effects of fire on pollen and nectar production in Echinacea angustifolia. This project has many excellent collaborators and is part of the MN ENTRF funded research on prescribed fire and ground nesting bees.
