Final report for GW24-008
Project Information
Farmers struggle to achieve adequate pollination for many berry crops, possibly in part due to the heavy reliance on a single pollinator species: the honeybee. We propose the development of additional species of bees for managed pollination of berries. This will strengthen the sustainability of our food systems while supporting existing natural pollinator diversity, and the economic benefits derived will improve farmers' lives by increasing profits and easing burdens.
We investigated the application of 4 lesser studied mason bee species on berry farms, all with some potential for berry pollination either shown through pilot study results, or previous scientific literature. We determined if they pollinated a target crop by ID’ing the pollen in their brood provisions and comparing it to crop pollen samples. Additionally, we tested these bees' propensity to being managed for agriculture by evaluating their nesting success. Together these strategies helped us, 1) Identify which bee-crop pairings show potential for future development, and 2) Compose recommendations for cost-effective management strategies.
We used targeted outreach to connect farmers with our research, including: a university extension publication, a YouTube video/ research talk, grower-grower field days, and presentations at grower meetings. We partnered with bee conservation-focused organizations to promote these materials to reach their respective memberships of largely bee managers and farmers (Orchard Bee Association) and backyard gardeners and bee enthusiasts (Oregon Bee Atlas) to, 1) Improve producer and beekeeper knowledge about mason bee management and its benefits and 2) Distribute discoveries about mason bee pollination of berry crops.
The final outcome of this project is to, 3) Publish on the management potential of these mason bees in berry crop systems in a peer-reviewed journal. The manuscript for this publication was drafted after the 2025 field season and is currently in the editing and revising stage prior to submission.
Research Objective 1: Investigate the aptitude of 4 mason bee species to be managed in commercial berry crop production using pollen ID.
Research Objective 2: Examine the nesting material preferences of 4 mason bee species to cost-effectively balance material attractiveness with management constraints.
Education Objective 1: Increase knowledge about mason bee management and its benefits among farmers and beekeepers by producing educational videos.
Education Objective 2: Distribute discoveries about berry pollination with mason bees to a broad audience of farmers, beekeepers, and backyard gardeners by publishing 2 factsheets.
Education Objective 3: Publish a peer-reviewed paper on the management potential of the 4 mason bees studied in berry crops.
Cooperators
- - Producer
- (Researcher)
- - Producer
Research
We researched crop pairings to determine which of the candidate bees are apt to pollinate which berries (Research Objective 1). Then, we evaluated candidate bees’ preferences for nesting habitats by analyzing their nesting rates over the field season (Research Objective 2).
Research Objective 1: Investigate the aptitude of 4 mason bee species to management in commercial berry crop production.
We determined which bee-crop pairings have the most support for future management at the commercial scale by testing each mason bee species in multiple berry crops, and determining if they collect crop pollen by sampling the provisions they provide in their nest straws. In our 2024 field season, we tested 4 Osmia bee species: Osmia bruneri, Osmia aglaia, Osmia ribifloris, and Osmia lignaria on different berry crops (Table 1). In 2025, we replicated our field releases, except for halving our site number in blueberries, for an attractant spray experiment described under Research Objective 2 (Table 2).
Along with our field experiments, we performed supportive analyses and experiments at the lab. First, we used 2024 pollen provisions to perform an in-depth analysis of pollen collection by O. lignaria and O. bruneri in strawberry and currant fields to better illuminate the strength of pollen preferences and level of fidelity to crop species in the presence of other forage. Following this work, we tested overwintering management strategies to improve performance of O. bruneri on berry crops, with an emphasis on improving emergence in the spring for currant bloom. Finally, we investigated the O. ribifloris provision proportions from within a screen house stocked with strawberries, blueberries, and currants, to better understand the preferences between these berry crop species.
The crops tested, and associated experimental methods are listed below in order of season phenology with currants blooming first, then high tunnel strawberries, then blueberries, and finally red and black raspberries.
Currants - O. bruneri, O. lignaria, and O. ribifloris
Currants: O. bruneri
Pollen analysis data from our pilot study in 2023 suggested that O. bruneri may selectively provision nests with currant pollen. In 2024, O. bruneri nesting was much lower than expected due to poor vigor in the bees. We were not able to achieve much emergence in currant fields.
In response to this low emergence success, we investigated strategies to increase emergence speed (time between post-winter incubation and emergence) and decrease early emergence mortality in 2025. In this experiment, we manipulated the temperature that adult Osmia bees overwinter. Approximately 100 bees (99-104 bees) were assigned to one of six treatment groups, in a complete block design that included both 4°C and 7°C and the three winter durations, 180, 210, and 240 days (Figure 1). At 180 days, we processed bees and assigned them to treatments, including removal from winter incubation temperatures and X-raying. Using the X-ray images, all cocoons that appeared to contain living bees (developed to the adult stage, bright white fat stores present, non-parasitized cocoon) were removed from their straw nests and placed in gel pill capsules. Each gel-capped cocoon was sorted into treatments to ensure that bee cocoons from the same nests were represented at approximately equal numbers within each treatment group. Gel caps were labelled with information on a bee’s source cage, source nest, and within-nest position, then adhered to a board with bees undergoing the same treatment procedure. Bee boards were then organized by temperature treatment and stacked in plastic bins before being placed back in the appropriate winter temperature incubator (4℃ or 7℃) once again (for 240-day and 210-day treatments) or, for the 180-day boards, removed to a 26℃ post-winter incubator. Bee boards for the later durations were removed 30 days apart to the same post-winter temperature incubator. After removal, bees were placed in 26℃ incubation and checked daily for emergence and mortality.
Figure 1: Methods figure for overwintering experiment.
Currants: O. lignaria
We released Osmia lignaria, and nesting was low, but we sampled pollen from 17 total nests. After these initial findings, we chose to look more closely at provision samples in strawberry and currants to determine patterns of pollen proportions collected within each provision. We determined proportions of pollen types collected within each provision by sampling 4 times on each pollen slide (NW,NE,SW,SE) at 40x, using a reference collection slide of pollen collected from strawberry and currant plants, and using a clicker counter to tally pollen types into two categories: Crop pollen and non-crop pollen.
Currants: O. ribifloris
Because of limited available bees for purchase, we chose not to test O. ribifloris in currants in 2024, and instead use the limited stock to test their abilities in blueberries. In 2025, we also placed 16 female and 34 male O. ribifloris in a screen house stocked with 40 blueberry plants, 40 currant plants, and a row of strawberry plants (Figure 2) to understand their preferences between berry crops without expending too many bees from our limited managed population.
Nesting activity was checked every work day (Mon-Fri) and completed nests were harvested and frozen within 3 days of being capped. After freezing, the entirety of all pollen provisions were sampled and processed into pollen slides for identification under a micrscope.
Figure 2: Berry screen house map
Strawberries - O. lignaria, O. bruneri
In both 2024 and 2025 we placed O. lignaria and O. bruneri in a strawberry high tunnel in northern Utah to test their effectiveness as high tunnel strawberry pollinators. We collected and analyzed this site's provisions for proportions of collected pollens using the quadrant counting method used above.
Blueberries - O. ribifloris
Osmia ribifloris is known as an Ericaceae specialist and is an efficient pollinator of the related rabbiteye blueberry (Sampson and Cane, 2000). Select research has shown that they readily pollinate high bush blueberries and nest abundantly (Torchio, 1990). In 2023, we released O. ribifloris at a small diversified berry farm in Utah with limited blueberry acreage and saw little nesting. In 2024, we placed O. ribifloris in high-acreage blueberry fields in Oregon at a stocking rate of about 50 bee cocoons per shelter at sic sites. In 2025, we placed at a much higher rate, 300 per shelter, and tested an attracted lure for it's ability to increase nesting. We narrowed to 3 sites, using two shelters at each site for a paired design. Lastly, as mentioned previously, we used a small proportion of our bees reared in 2024 to stock a berry screenhouse and test pollen preferences between strawberries, currants, and blueberries.
Red and Black Raspberries - O. aglaia, O. bruneri, O. lignaria
Raspberries: O. aglaia
We discovered through talking with extension agents and growers that red raspberry is not a large export in Oregon, so we decided to place Osmia aglaia on black raspberry in Oregon (2 sites) and pair that with 1 black raspberry site stocked with Osmia bruneri in Utah.
Raspberries: O. lignaria and O. bruneri
Osmia bruneri and O. aglaia are both summer flying bees that emerge with the blooming of red raspberries (early to mid-June in Northern Utah). While O. aglaia is a potentially productive raspberry pollinator in commercial fields, Osmia bruneri has only been tested on the berry in limited caged studies (Andrikopolous et al., 2018) and provided us an opportunity to test this application for the first time. We released O. bruneri in two raspberry fields in Utah in 2024 and 2025. In Utah, where red raspberry is more economically important and more commonly grown, we also maintained two red raspberry sites with Osmia bruneri and Osmia lignaria (Table 1). To pair well with O. aglaia, we also tested them on black raspberries.
Methods:
Site Selection
We worked to identify suitable fields and partner growers for each crop throughout the winter of 2023/2024. We reached out to growers that we had already worked with (currant, strawberry, blueberry, and raspberry growers in Utah), and identified new growers through our supporters at Utah (Dr. Brent Black) and Oregon State University (Dr. Andony Melathopolous) (see letters of support).
Table 1: Bee-crop pairings tested and our levels of field replication in each state tested in 2024 with changes from 2025 in bold.
OB = Osmia bruneri, OA = Osmia aglaia, OL = Osmia lignaria, OR = Osmia ribifloris
| 2024 | Currants | Strawberries | Blueberries | Black Raspberries | Red Raspberries | Boysen Berries |
| Bee Species | OB, OL | OB*, OL* | OR | OA, OB | OB, OL | OA |
| Utah | 2 | 1 | 1 | 1 | 2 | 0 |
| Oregon | 0 | 0 | 6 | 2 | 0 | 1 |
*high tunnel
Table 2: Bee-crop pairings tested and our levels of field replication in each state tested in 2025 with changes from 2024 in bold.
OB = Osmia bruneri, OA = Osmia aglaia, OL = Osmia lignaria, OR = Osmia ribifloris
| 2025 | Currants | Strawberries | Blueberries | Black Raspberries | Red Raspberries | Boysen Berries |
| Bee Species | OB, OL, OR* | OB**, OL**, OR* | OR | OA, OB, OL | OB, OL | OA |
| Utah | 2 | 1 | 1 | 1 | 2 | 0 |
| Oregon | 0 | 0 | 3 | 2 | 0 | 1 |
*berry screen house
**high tunnel
Osmia bruneri has been managed for research projects at the USDA ARS Pollinating Insects Research Unit (home institute of the project PI, Dr. Graham) since the 1980s. We had enough bees in management to fulfill the needs of this project at no cost.
Osmia lignaria, O. ribifloris, and O. aglaia bees were purchased from our collaborator Kimball Clark, who manages and sells them.
Field Work
Selected sites were monitored for the start of bloom and bee shelters (solitary bee domiciles fit with nesting substrates) were placed when buds appeared in Utah and at 10%-50% bloom in Oregon. We monitored the sites closely at this stage and the shelters were stocked with bees of the appropriate bee species at 10% - 50% bloom.
During the first week the bee condos were placed in 2024, a pollen survey was conducted. Pollen from flowering plants within the immediate field radius of the nesting shelter site was sampled and the exact location of the pollen sample with a determination of the plant species was curated using iNaturalist. Collected samples were used to create a pollen reference library out of microscope slides of dyed pollen grains. While our original plan was to collect from 300m around fields, further evaluation of pollen samples collected in 2023 revealed weaknesses in the methods. Wild plant references from 2023 were difficult to make use of (not much pollen available, and failure to match what bees collected). So, we instead focused on collecting from plants that were highly abundant directly within or around berry fields, and pollen was ID'd mainly using references of just the crop pollens. This way we determined if the bee was pollinating berry crops, but many non-crop pollens were not identifiable.
Regular site visits during bloom were conducted. At each visit, we removed and replaced any finished nest straws and sampled their pollen provisions (described below).
Pollen Analysis
At the lab, we took X-rays of the collected straws. The X-ray image of the nest tube was used to locate and count the brood cells (Image 1). We randomly selected brood cells (usually one per nest) for pollen analysis and then carefully cut a window through the nest and into the cell, avoiding the larva. The pollen provision was then sampled, and the window taped shut and the pollen sample given a unique sample ID. Provision samples were processed into slides of dyed pollen grains and were identified as either crop pollen or "other" using the reference library of crop pollens.
Image 1: X-ray image of Osmia nests pulled from a project site in 2023. Nests are arranged side-by-side.
Taken together, these data provided us with information on nesting rates and pollen preferences of each bee species for each crop.
As Described previously (see "Currants" section), we examined the proportion of pollen types collected for strawberry, classifying them as their crop pollen or "other" non-crop pollens, for Osmia lignaria and Osmia bruneri in 2024.
Pollen proportions within provisions were deemed to be purposeful at 5% or greater abundance within samples. As such, presence of 95% or greater of crop pollen was considered to be evidence of complete pollen fidelity, and collection of crop pollen of less than 5% was deemed no evidence of crop pollen fidelity.
Data analyses
Much of our data were observational, such as the percentage of crop pollen collected, and bee nesting returns. One of the most important results is establishing if each bee species will (or will not) collect crop pollen; a vital first step in determining if they are viable for managed pollination. We also needed to determine if the bees are nesting at high enough rates to indicate that they are actively visiting the crops in that field and if they can be managed sustainably. Sufficient nesting is needed to make the system feasible long-term, as nests provide the bees used for the following year. We set a target bee return rate of 100%, a measurement common in the mason bee industry to indicate system sustainability, as it explains that the number of viable brood collected at the end of the field season is equivalent to or higher than the number of adults released initially.
Research Objective 2: Examine the nesting material preferences of 4 mason bee species to cost-effectively balance material attractiveness with management constraints.
Rationale:
While promising for pollination, mason bees present unique challenges to bee managers. Honey bees inhabit large social networks contained in hive boxes. Female worker bees are generally unable to reproduce and are thus dependent on the survival of a hive-stuck queen for reproductive success, solidifying evolutionary-driven cooperation. In contrast, Osmia are solitary bees, where each female is reproductively capable and forms nests independently. This makes the solitary bee more efficient on a per-bee level, as a single female bee will collect more pollen than a honey bee as the sole provider for her nesting brood (Lyu et al., 2023). That said, this independence makes managing solitary mason bees is markedly different from managing communal honey bees, and thus increased attention is needed to understand mason bee proclivities to existing and novel strategies for management. Research in the area of Osmia nest attractiveness is of particular interest, as previous work largely focuses on a few focal Osmia species, incomplete or absent for the promising mason bees tested here.
We analyzed the nesting material preferences of mason bees systematically to optimize nesting returns by increasing nest attractiveness. We set out solitary bee shelters (used also in Research Objective 1) with a variety of materials used in rearing Osmia lignaria: reeds, straws, and wood laminates ( Each material was provided in the ideal diameter for our small bees [3mm], O. aglaia and O. bruneri, and our large bees [5mm], O. ribifloris and O. lignaria). We monitored nesting rates using each material type to determine preferences for each species. And, while nesting material preferences are important in teaching us how to encourage high return rates (number of brood per adult released), they must be grounded in realistic management considerations to be useful to bee managers. We originally aimed to determine the labor and monetary costs of each material to identify a balanced approach to nesting material recommendations, taking into account both the bee preferences and the price of each nesting material. Unfortunately, we received no nesting in wood blocks during our study, so plans to understand variable labor requirements were not feasible.
Methods:
Nest design
There were two condo versions, one for large bees and one for small. Each had reeds, wooden laminates, and paper straws as nesting material options.
Image 2: Nest Shelter Design
Note. Wood laminates (Upper left and lower hex), black-painted paper straws (upper right hex), and reeds (gaps between hexes), (design: Kimball Clark, nativebees.com).
Nest preference evaluation
Removing capped nests regularly for Research Objective 1 also allowed us to catalog what types of nesting material are preferred by the nesting females of each species. Replacing capped nests with empty nests of the same materials ensured that nesting options always remained available. We counted the total capped nests at each site, evaluated preference per bee species, and examined total nest counts for each nesting material type, each bee species, and each crop.
We further attempted to evaluate the practicality of management based on material preferences by calculating the cost of each species’ utilized materials. Material costs were expressed as a sum of the cost of materials purchased in bulk and the cost of labor to process and rear out bee cocoons nested in those materials. To understand the cost of materials, Kimball Clark (bee producer) provided some basic financial data on material purchase and manufacturing costs. Our next steps would be to then track the number of hours it takes to process each material, from receiving the nest to cleaning it to storing it for the winter months, to understand the labor contribution to the total cost of management per material. The compiled costs would then be compared with the bees’ preferences, and the most cost-effective management strategies would be determined and ranked.
Because we had no nesting in wooden laminates in 2024, we were unable to gather useful data on labor costs, but we did trial methods and will use these next year, assuming nesting is more successful. We also spoke with larger scale Osmia bee producers to understand costs on a broader scale (beyond the local vendor we work with), and used these conversations to evaluate differences in labor and material costs.
2025 O. ribifloris Lure Test
Figure 3: 2025 Oregon blueberry sites.
In 2025, we chose to test an Osmia attractant lure spray for it's ability to increase nesting in O. ribifloris. This lure has successfully increase nesting rates with O. lignaria, O. cornuta, and O. cornifrons (Artz et al., 2013, 2014; Eeraerts, 2024; Pinilla-Gallego et al., 2022), but has not been tested on O. ribifloris previous to this work. The six shelters were placed in pairs where one had been sprayed with attractant and the other left as a control. .05 meters (10ft) apart at each of three different farm sites. The attractant lure (patent number US 9301521B2) was sprayed onto shelters and bundles of paper straws for all positive treatment shelters. To ensure that removing straws for pollen collection did not weaken the lure over time, we sprayed extra bundles of straws as well, which we used to replace capped nest straws throughout the season. We used a spray bottle that releases 0.22ml per spray and sprayed each bundle of 36 straws and shelters twice, and then left them to air dry. Control and lure materials were stored separately at all times before set-up in the field. Time between spray application and bee release was 27 days, and the spray's chemistry and effectiveness is not expected to significantly alter within this window (Pitts-Singer et al., 2014).
Data analyses
Nesting - To assess if bee species have nest material preferences (data: counts of completed nests in each material), we tried to use generalized linear mixed effects modeling (R package lme4). However, concerns with modelling these data (unpredictability between years within species, and overdispersion issues among multiple distributions), drove us to take a simpler approach, (We suspect much higher site replication, and likely much higher bee release numbers are required to properly model material preferences), instead using X2 Goodness-of-Fit tests to determine if differences in nesting between materials were significant within species.
Lure - To understand what effect the attractant lure had on nesting of O. ribifloris in Oregon blueberry fields we measured the significance of differences in total nest counts by material using Pearson X2 tests (chisq.test, R version 2025.05.1+513) with Yate’s continuity correction. We did the same for our nest counts at each site between treatments and controls. We then used generalized linear modes (GLMs) (glmmTMB [Brooks et al., 2017], R) to analyze differences in per-nest mortality and per-nest cell number with respect to site and material differences. The most appropriate model families were determined for each model first using log likelihood comparisons (loglik()) between families that fit our data types, then, testing for fit and resolving overdispersion using QQ plots with the DHARMa package in R (Hartig, 2026). For both models, AICc rankings, using the dredge (Burnham & Anderson, 2002) and MuMIn (Bartoń, 2010) packages in R, were used to select and exclude variables to include in the models, and emmeans package (Lenth, 2025) was used to calculated Estimated Marginal means in terms of the response variables and perform Tukey pairwise comparisons. After model selection cells per nest was ultimately modelled with a Poisson distribution, and included site, treatment (lure and control), and material as fixed effects. Mortality was ultimately modelled with a beta-binomial distribution, with site as a fixed effect.
References:
Andrikopoulos, C. J., & Cane, J. H. (2018). Comparative pollination efficacies of five bee species on raspberry. Journal of Economic Entomology, 111(6), 2513-2519.
Artz, D. R., Allan, M. J., Wardell, G. I., & Pitts‐Singer, T. L. (2013). Nesting site density and distribution affect Osmia lignaria (H ymenoptera: M egachilidae) reproductive success and almond yield in a commercial orchard. Insect Conservation and Diversity, 6(6), 715-724.
Artz, D. R., Allan, M. J., Wardell, G. I., & Pitts-Singer, T. L. (2014). Influence of nest box color and release sites on Osmia lignaria (Hymenoptera: Megachilidae) reproductive success in a commercial almond orchard. Journal of Economic Entomology, 107(6), 2045-2054.
Bartoń, K. (2010). MuMIn: Multi-Model Inference (p. 1.48.11) [Dataset]. https://doi.org/10.32614/CRAN.package.MuMIn
Brooks, M. E., Kristensen, K., Benthem, K. J. van, Magnusson, A., Berg, C. W., Nielsen, A., Skaug, H. J., Mächler, M., & Bolker, B. M. (2017). glmmTMB Balances Speed and Flexibility Among Packages for Zero-inflated Generalized Linear Mixed Modeling. The R Journal, 9(2), 378–400. https://doi.org/10.32614/RJ-2017-066
Burnham, K. P. and Anderson, D. R (2002). Model selection and multimodel inference: a practical information-theoretic approach. 2nd ed.
Eeraerts, M. (2024). Attractant spray enhances nesting preference and reduces macroparasite infestation of Osmia cornuta. Journal of Applied Entomology, 148(8), 900-906.
Hartig F (2026). DHARMa: Residual Diagnostics for Hierarchical (Multi-Level / Mixed) Regression Models. R package version 0.5.0, https://github.com/florianhartig/dharma.
Lenth R, Piaskowski J (2025). emmeans: Estimated Marginal Means, aka Least-Squares Means. R package version 2.0.1, https://rvlenth.github.io/emmeans/.
Lyu, Z., Zhou, T., Sun, M., Feng, M., Guo, W., Nie, L., ... & Yu, Y. (2023). Exploratory comparison of flower visiting behavior and pollination ability of mason bees, bumble bees, and honey bees. Journal of Economic Entomology, 116(6), 1949-1956.
Pinilla‐Gallego, M. S., Rowe, L. M., Gibbs, J., Pitts‐Singer, T. L., & Isaacs, R. (2022). Improving Osmia lignaria and O. cornifrons (Hymenoptera: Megachilidae) retention with preferred nest materials and attractant spray. Journal of Applied Entomology, 146(6), 743-752.
Pitts-Singer, T. L., Kemp, W. P., Moreland, D., Peterson, S. S., Buckner, J. S., & Hagen, M. M. (2014). Bee attractants (Patent No. US 9301521B2). US Patent and Trademark Office.
Sampson, B. J., & Cane, J. H. (2000). Pollination efficiencies of three bee (Hymenoptera: Apoidea) species visiting rabbiteye blueberry. Journal of Economic Entomology, 93(6), 1726-1731.
Torchio, P. F. (1990). Osmia ribifloris, a native bee species developed as a commercially managed pollinator of highbush blueberry (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society, 427-436.
Research Objective 1: Investigate the aptitude of 4 mason bee species to be managed in commercial berry crop production using pollen ID.
Summary:
We released bees of our focal species on berry farms and gathered pollen from nests berry completed in Utah and Oregon. Pollen ID was fairly successful, allowing bees to be associated directly with pollination of target crops of interest. This was true of strawberries, currants, and blueberries. However, black and red raspberries proved difficult to identify morphologically. Osmia bruneri, O. aglaia, and O. lignaria were placed in red and black raspberry fields, and 74%-100 % of provisions contained raspberry "type" pollen. This is a promising initial result, but it is complicated by the uncertainty of morphological pollen identification within this group. As seen in Figure 1, many pollen types within the Rosaceae family (apples, pears, cherries, etc.) resemble raspberry and blackberry pollens. Because of their morphological similarities with other pollens, we classified provisions as containing pollens of "raspberry-type", instead of raspberry pollen.
Figure 1:
A. Distinct raspberry "type" pollens collected from Osmia bruneri provisions.
B. Common Rosaceae pollens that are difficult to morphologically distinguish.
A.
B.
Table 2: Summary of samples from Osmia bruneri provisions in 2024
| Crop | Black Raspberry | Red Raspberry | Currant | Blueberry |
| High nesting activity during bloom? | yes | yes | no | no |
| Total Pollen Samples | 35 | 22 | 33 | 2 |
| provisions with crop-type pollen | 29 | 22 | 1 | 0 |
| provisions without crop-type pollen | 6 | 0 | 32 | 2 |
| % of total with crop-type pollen | 82% | 100% | 3% | 0% |
O. bruneri
In 2024 Osmia bruneri collected 82% black raspberry-type pollen, and 100% red raspberry-type pollen (keeping the previous constraints in mind). In contrast, very little currant, and no blueberry pollen was collected by O. bruneri in 2024. For currants, this was a stark contrast to 2023, where we found currant pollen in the two O. bruneri provisions. In 2024 however, we had trouble emerging Osmia bruneri early in the season, so much of the nesting observed (30 of the 33 samples) were collected outside of the peak bloom window for currants. A collaborator later tested O. bruneri vigor in the lab, and found that many bees were too weak from the previous season to emerge from straw nests. Thus, we suspect that many of our bees failed to emerge at all.
Table 3: Summary of samples from Osmia bruneri provisions in 2025
| Crop | Black Raspberry | Red Raspberry | Currant | |
| High nesting activity during bloom? | yes | yes | no | |
| Total Pollen Samples | 7 | 30 | 22 | |
| provisions with crop-type pollen | 7 | 29 | 0 | |
| provisions without crop-type pollen | 7 | 1 | 22 | |
| % of total with crop-type pollen | 100 | 97 | 0 |
In 2025, we received 22 O. bruneri nests from currant fields (Table 3), but only two nests were harvested during bloom. While we released bees during early bloom, nesting did not initiate until bloom was mainly over, possibly because bees took longer to emerge from cocoons so early in the spring. Suspecting the early season phenology to be at fault for poor O. bruneri emergence success and emergence speed in currants, we conducted a study to attempt to expedite emergence using higher incubation temperatures. This experiment revealed that O. bruneri emerge more readily in response to warmer temperatures (Figure 2), and do not experience outsized mortality when removed form winter incubation for currant pollination, at around 180 days (Figure 3).
Even at 180 days of winter incubation, which would emerge the managed bees in time for currant pollination, overall emergence was around 85%, suggesting that failing to emerge is not the sole explanation for Osmia bruneri's poor performance in currants. Instead, it seems that synchronizing with bloom may have been the primary issue for our lack of currant pollen collection in 2024 and 2025, as bees overwintered at 4oC took around 11 days to emerge. Placing bees at 10% bloom from post-winter incubation of ~7 days may have meant that the bulk of currant bloom was over by the time that bees would have emerged, mated, and begun nesting (these latter processes can take an additional 5-7 days after emergence). This reflects our informal observations from 2025, where O. bruneri were not observed actively nesting at the nest when we checked during bloom (Table 3)
Figure 2: Model-Predicted days to emerge from post-winter incubation.
Figure 3: Model-Predicted percent mortality (#bees that would not emerge within treatment context).
Table 4: Summary of samples from Osmia aglaia provisions in 2024
| Crop | Black raspberry | Boysenberry |
| High nesting activity during bloom? | yes* | yes |
| Total Pollen Samples | 49 | 24 |
| provisions with crop-type pollen | 36 | 23 |
| provisions without crop-type pollen | 13 | 1 |
| % of total with crop-type pollen | 74% | 96% |
*trailing end of bloom (~70% spent)
In 2024, Osmia aglaia collected 74% black raspberry type pollen and 96% boysenberry type pollen. This is in-line with our expectations from the literature, but concerns with morphological ID (Figure 1) should be considered before being too sure about these hopeful results. In 2025, a mid-nesting pre-harvest spray to black raspberries may have interrupted O. aglaia reproduction. Our population did not reproduce well, yielding 326 individuals. In order to protect our bee manager's remaining population, we did not sample pollen from bees in this group. Since results in 2024 were fairly definitive, and reflected findings from the literature (Adrikopoulos & Cane, 2018), we were comfortable making conclusions based on 2024 results.
Table 5: Summary of samples from Osmia lignaria provisions in 2024
| Crop | Strawberry | Currant | Red Raspberry |
| High nesting activity during bloom? | yes | yes | yes |
| Total Pollen Samples | 10 | 17 | 1 |
| provisions with crop-type pollen | 4 | 1 | 1 |
| provisions without crop-type pollen | 6 | 16 | 0 |
| % of total with crop-type pollen | 40% | 6% | 100% |
O. lignaria
Osmia lignaria in 2024 collected entirely raspberry-type pollens in 2024. Among 17 samples from currant fields, 1 was identified to be currant-type pollen. Re-analysis of 2023 pollen also revealed that 3 of the 14 nests O. lignaria nests also contained currant-type pollen.
Additionally, they flew well in a Utah strawberry high tunnel, collecting strawberry pollen in 40% of provisions. We were able to do approximate measures of proportions of pollen types within provisions as well. We used these approximations to understand how loyal each bee was to collecting strawberry pollen in the high tunnel. We compared these provisions with the 2023 O. bruneri provisions to show the difference in collection patterns (Figure 4). From 10 pollen provisions, we observed consistent collection from Osmia lignaria in 40% of provisions. While Osmia bruneri from 2023 collected pollen in 50% of provisions, overall, they collected less proportional crop pollen per sample when compared to O. lignaria.
Because our sample sizes were low, with 10 and 6 pollen provision samples respectively, these results may not represent the diet breadth and pollen collecting behavior of their source populations. Rather, these findings prompt further investigation into the proportion of target pollen collected relative to alternate resources on the individual sample level, and not just across different randomly sampled nests. We took these results and altered our methods for pollen collection in our 2025 Oregon blueberry fields, collecting and sacrificing some nests to track pollen proportion changes within the nest level.
While O. lignaria were released in 2025, we saw no nesting by this species within a developmental window where pollen collection was possible, and thus no pollen was evaluated.
Figure 4: Osmia provision pollen types from a strawberry high tunnel in Utah.
We were able to make a similar comparison by looking deeply at the currant pollen collected by O. lignaria (in 2024) and O. bruneri (in 2023). We observed that O. bruneri shows a stark pattern in currants, collecting provisions with 100% currant pollen, whereas in this crop, O. lignaria tended to mix pollens when it collected any currant at all (Figure 5).
Figure 5: Osmia provision analysis form 2 Utah currant fields (currant pollen proportion is displayed in pink/plum, non-currant pollen in gray).
O. ribifloris
Table 5: Summary of samples from Osmia ribifloris provisions in 2024
| Crop | Blueberry |
| High nesting activity during bloom? | yes |
| Total Pollen Samples | 15 |
| Samples with crop-type pollen | 15 |
| Samples without crop-type pollen | 0 |
| % of total with crop-type pollen | 100% |
In 2024, Osmia ribifloris bees placed in blueberry fields in Oregon largely absconded but one nest site provided four total nests from which 15 samples of pollen were taken and identified. All of these were majority blueberry pollen. Bees from this site also had "good returns." In other words, we got 48 bee brood cocoons after releasing ~45 adults, indicating a 107% return (Bee managers want to see >100% returns to maintain and grow their managed populations). While promising, the five other shelters had not nesting activity.
In 2025 Osmia ribifloris were deployed at a higher stocking density (~300 adults) and nested much more successfully. Blueberry pollen appeared to be a major presence in all provisions throughout this entire period. Microscopically analyzing pollen from 27 randomly sampled pollen provisions (from 27 nests) revealed that 22 samples contained greater than 95% blueberry pollen, and 11 of these were purely (100%) blueberry. Five nests had less than 95%, with our lowest sample still having 88% blueberry pollen, and only 12% non-blueberry (Figure 6).
Additionally, 18 nests collected on May 7th, 2025 were set aside and sacrifices so that we could track pollen collection by single females across individual nest cavities. Instead of one random sample per nest, every provision from these nests was sampled for a total of 155 pollen samples. 74 of these samples were purely blueberry pollen (100%), and 75 additional samples contained between 99% and 95% blueberry pollen. Females seemed to collect blueberry pollen consistently across the same nest, with one exception. This exception had an increasing proportion of blueberry pollen as cells were laid, 1st cell = 1%, 2nd cell = 7%, 3rd cell = 84%, 4th cell = 65%, 5th cell = 99%, 6th cell = 93%, 7th cell = 99% (Figure 7).
Figure 6: Pollen Proportions from O. ribifloris nests
Figure 7: Proportional Blueberry Pollen Presence in a Single Nest with Mixed Provisions
At the lab, 16 female and 34 male O. ribifloris were released within a screen house and flown on blooming blueberries, currants, and strawberries. Two nests were crafted during this period. Nest 1 had eight nest cells that produced eight pollen samples, and Nest 2 had three nest cells, for a total of 11 pollen provision samples. These samples displayed a mixed collection of currant and blueberry pollen (Figure 8). Currant pollen grains, roughly half the size of blueberry pollen grains, composed 0-60% of pollen collection when accounting for size by multiplying the number of currant pollen grains by the size ratio 1/2. Blueberry pollen composed the majority of most provisions, but only surpassed 95% in one, showing that fidelity for blueberry pollen in this context is distinctly lower than fidelity displayed in Oregon blueberry fields. No strawberry pollen was identified in any samples.
Figure 8: Pollen proportion from O. ribifloris berry screen house provisions
Research Objective 2: Examine the nesting material preferences of 4 mason bee species to cost-effectively balance material attractiveness with management constraints.
Figure 9: stacked bar chart showing nest counts by material as proportions by species in 2023
Figure 10: stacked bar chart showing nest counts by material as proportions by species in 2024
Nesting rates appear to differ by material, species, and year (Table 6). Notably, O. ribifloris seems to range widely in it's choice of material, entirely avoiding wooden laminated in 2023 and nesting in them the more than any other material in 2024 (Figures 9 and 10). We found that each species had greater differences in nesting by material than would be expected by chance, expect for O. ribifloris in 2024 (Table 7), who created only 6 nests in that year (Table 6).
Table 6: nest counts by material for 2023 and 2024.
Table 7: X2 results for Osmia nesting preferences
| Bee | 2023 X2 | 2023 df | 2023 p | 2024 X2 | 2024 df | 2024 p |
| Osmia aglaia | NA | NA | NA | 118 | 3 | < .0001 |
| Osmia bruneri | 374 | 3 | < .0001 | 133 | 3 | < .0001 |
| Osmia lignaria | 27.3 | 2 | < .0001 | 25 | 3 | < .0001 |
| Osmia ribifloris | 21 | 2 | < .0001 | 4 | 2 | 0.14 |
For general costs of each material, we broke down the cost per nesting cavity provided to the bees. Kimball Clark reported that per nest cavity costs for phragmites or bamboo reeds is 10 - 25 cents, for Maple wooden laminates it is around 83 cents, but for a one-time purchase that can be reused. Because we had no nesting in most of our drilled wooden laminate shelters in 2024 (figure 10) we were not able to appropriately test the time it takes to clean and process wood laminate nesting materials, so we could not compare costs with labor need.
We connected with other Osmia producers and the Orchard Bee Association’s annual meeting. Here, we toured commercial bee production facilities and observed the industry technology used to efficiently process Osmia bees for large scale management. At this large scale, we have determined that wooden laminates are by far the most economical choice, as technology has been developed to process them en mass reducing labor costs substantially. The reusability of the wooden laminates is also important, with many of them being reused indefinitely. We will still pursue the labor analysis next year for the information it may provide to smaller bee management operations, but a scalable model for our other materials options seems to be clearly unable to match the efficiency and ease of using wooden laminates.
In 2025, we also went forward with testing the attractant lure spray on O. ribifloris to try and increase nesting rates for this species. Here, we found that the lure was somewhat effective at increasing total nesting at two sites, with site 2 showed a significant increase in nesting between lure and control treatments (X2 = 12.45, df = 1, p = 0.004), site 3 having a numerical increase that failed to reject the null hypothesis at the .05 threshold but is marginally significant (X2 = 2.78, df = 1, p = 0.095) amd site 1 seeing a decrease in nesting with the lure that was not statistically significant (X2 = 0.1, df = 1, p = 0.75). Looking at cells per nest, or the density of progeny within nests that were within lure and control shelters, we found that a greater number of bees were laid per nest in lure shelters compared to control. The average number of cells per nest within materials sprayed with the lure was significantly greater compared to control materials that hadn’t been sprayed (Figure 11) (X2 = 8.00, df = 1, p = 0.005). Lure nests across our sites had an average of 8.21 cells per nest (EMM 8.21, SE = .431, CI[7.41, 9.10]), and controls averaged 6.71 cells per nest (EMM = 6.71, SE = 4.35, CI = [5.90, 7.62]). (Figure 11).
Figure 11: Nest evaluations of Attractant Lure Effectiveness
Figure 12: Total O. ribifloris returns by site
Site differences may be an equally important factor influencing total nesting, according to our results (Figure 12). Material type did not significantly affect the number of cells laid within each nest (X2 = .37, df = 1, p = 0.54), whereas cells per nest differed significantly by site location (X2 = 11.72, df = 2, p = 0.003).
Research outcomes
Objective 1:
Our research exploring the pollen collecting tendencies of four Osmia species has revealed stark differences in their affinities to different berry crop flowers. These findings highlight the importance of understanding solitary bee management on the species level, and being conservative with recommending only Osmia lignaria, the most prolifically managed mason bee in the U.S., for every crop system. From pollen identification of bee provisions three things have become clear - first, different bee species collect different berry pollens at distinct rates. Second, the amount of loyalty to a crop flower differs based on bee species, so that even when bees will collect from a crop flower, it may be less than 10% (Osmia bruneri in strawberry for example) of their total pollination for the day, or up to 100% (Osmia ribifloris in blueberry). Third, context of the entire foraging landscape matters, with screen house O. ribifloris collecting less blueberry, and more currant pollen than expected from such strongly loyal blueberry bees.
We recommend that further research with the lesser managed bees of the genus (Osmia ribifloris, Osmia aglaia, Osmia bruneri, among others) is conducted. Pollen provision identification is fairly harmless to overall managed bee populations, allowing for research on species who's managed populationas are smaller due to low demand. The return for such research is reliable evidence that bees will visit crop flowers of interest. However, in line with Objective 2, maintaining these populations remains a central challenge, necessitating a measured approach where population-boosting management strategies are also concurrently investigated.
We recommend molecularly identifying sub-samples of pollens when possible to ensure that morphological identifications are certain (in the case of identifiable pollens for currants, blueberries, and strawberries) and that morphologically indistinct pollens (raspberry, blackberry, black raspberry, and boysenberry) are being correctly identified and not being mistakenly assigned. We secured a grant at our primary institution (Utah State University) to send 50 pollen samples for DNA sequencing. While still underway, these results will provide us with further assurance of morpohlogical identifications and insight on our uncertain IDs.
Importantly, we found that at lest two Osmia species (O. bruneri and O. lignaria) pollinate and nest within an open-ended high tunnel. In the case of ever-bearing or day-neutral strawberries, bloom in high tunnels can last from early spring to early fall, so providing a bee that can fly longer periods in the variable weather conditions of the high tunnel without becoming fatigued or dispersing is vital. We think both O. bruneri and O. lignaria could be utilized for the two environmental extremes experienced in high tunnels (the early spring bee O. lignaria for early cool temperatures and overcast weather, and summer flying O. bruneri for high humidity and heat). Strawberry pollen analysis also revealed fascinating patterns in pollination loyalty. O. lignaria may be the best pollination option for this system because of their collection of strawberry pollen and their ability to fly in the cooler temperatures experienced early on in the bloom period, as well as their established efficacy as strawberry pollinators (Horth & Campbell, 2018).
Objective 2:
Variable nesting rates in our bees surprised us, especially with the commercially managed Osmia lignaria. We found that, at most sites, returns for O. lignaria and O. ribifloris were under 100%. The typical management strategy to promote population growth is to allow bees a year to nest in completely natural habitat, in between years spent on farms. While we initially thought increasing the attractiveness of nests would reduce the need to supplement Osmia populations, it has becoming clearer that we need consider nutrition and nesting materials provided by the surrounding habitat. There are positive associations between native bee abundance and semi-natural habitat (Eeraerts et al., 2021, 2022; Lundin et al., 2017; Gibbs et al., 2016). While we focused on nesting cavity material options initially, we now believe that the partition material and diverse pollen access may be just as vital. Placing bees near or within areas adjacent to crop fields with natural vegetation and undisturbed soil may give bees easy access to leaf and/or mud used in the internal construction of cavity nests, prompting them to stay at a nest shelter, and provide vital nutritional supplementation.
We intended to look at the economics of nesting materials directly using cost benefit analyses and quantifications of labor hours. However, we quickly realized that more foundational questions took priority. Certainly, a cost benefit analysis will be vital in the future, but first we need to establish management practices that successfully sustain populations as a bare minimum. Rather than focusing on material alone, we now suggest that researchers or industry interests compose full enterprise budgets for each Osmia species that is sustainably managed (100% or greater returns every year) encompassing the costs to sustainably reproduce managed populations. This will help guide bee managers and researchers working with less established species understand the likely costs of successful management in their pursuit of further funding for research and establishment of economically sustainable practices.
O. ribifloris tested in Oregon in 2024 nested very little, so in 2025 we explored the effectiveness of the Osmia attractant lure spray. While results are somewhat promising, O. ribifloris seems to respond less strongly than expected given findings with other Osmia species. This information is vital, as we believe it suggests, that O.ribifloris are considering multiple local landscape, nest level, and climate factors when deciding whether to nest or abscond. Future research in this species should explore surrounding landscape and keep close track of bloom patterns in crop and wild plants, to better understand the drivers of O. ribifloris reproduction in management.
Research Conclusions:
Through this research and it's associated outreach, we found that growers and extension faculty are excited to explore and invest in the less established Osmia pollnators subject in this work. We also noticed that many people we spoke with were not previously aware of any solitary bee management, even the somehwat popular orchard pollinator, Osmia lignaria. While excited, most growers are discourage by the premium price of most ready-to-emerge Osmia cocoon kits (generally priced 25 cents to $1.50 per bee and sold at 1-2 hundred bees per acre). Therefore, our work researching nesting preferences proved the most grower-relevant of our research objectives, as it was most associated with cost reduction of mason bees through increasing population sustainablity. That being said, this research objective also proved the most preliminary, with multiple drivers for nest attractiveness that we did not anticipate based on our literature reviews on the topic, making analysis of nesting material preferences quite difficult. Even preliminarily however, this work allows bee managers to avoid certain pitfalls, like expecting the attractant lure to increase O. ribifloris nesting very significantly, or placing this species in a shelter with one material type (see Objective 2 results - Osmia ribifloris). Additionally, our first research objective results provide evidence of intentional berry crop pollen collection in a multitude of contexts that can assist researchers in funding further applied research on the management of various Osmia species for US small fruit.
The studies funded by this grant contribute basic and applied research on solitary mason bees, and directly assist mason bee industry professionals by delivering novel species-specific information on pollen and nesting preferences. We hope this work helps those inventive industry professionals (many of whom have become close friends through this grant's collaborations) who push progress towards more sustainable agricultural practices.
Citations:
Eeraerts, M., Van Den Berge, S., Proesmans, W. et al. Fruit orchards and woody semi-natural habitat provide complementary resources for pollinators in agricultural landscapes. Landscape Ecol 36, 1377–1390 (2021). https://doi.org/10.1007/s10980-021-01220-y
Eeraerts, M. (2022). Increasing wild bee richness and abundance on sequentially flowering cultivars of a pollinator-dependent crop. Agric Ecosyst Environ. 325, 107745. doi: 10.1016/j.agee.2021.107745
Gibbs, J., Elle, E., Bobiwash, K., Haapalainen, T., & Isaacs, R. (2016). Contrasting pollinators and pollination in native and non-native regions of highbush blueberry production. PloS one, 11(7), e0158937.
Horth, L., & Campbell, L. A. (2018). Supplementing small farms with native mason bees increases strawberry size and growth rate. Journal of Applied Ecology, 55(2), 591-599.
Ola Lundin, Kimiora L. Ward, Derek R. Artz, Natalie K. Boyle, Theresa L. Pitts-Singer, Neal M. Williams, Wildflower Plantings Do Not Compete With Neighboring Almond Orchards for Pollinator Visits, Environmental Entomology, Volume 46, Issue 3, June 2017, Pages 559–564, https://doi.org/10.1093/ee/nvx052
Education and Outreach
Participation summary:
Education Objective 1: Increase knowledge about mason bee management and its benefits among farmers and beekeepers by producing two educational videos.
Rationale:
To increase the sustainability of pollinator-dependent agriculture, it is important that literacy about pollinator management increases among growers and beekeepers alike. We want to make managing other types of bees feel more approachable, so we will create broadly accessible content to introduce people to the topic. We originally planned to create 2 videos. One describing the basics of managing mason bees, while the other would describe and promote the pollination and environmental benefits of doing so. After our second year of research results were analyzed however (year 1 of this project) it started to become clear that our research questions only began to unravel the complex management preferences of our mason bee species, and that creating management recommendations at this stage would be immature. We chose instead to share our open questions and our research trials through posting a video of our research talk to the Orchard Bee Assocation Youtube. And, while informative for audiences who are aware of mason bee potential, we also sought to inform a more general grower audience by participating in 2 farmer-farmer field days, one in each state that this project took place in (Utah and Oregon).
Objective 2: Distribute discoveries about berry pollination with mason bees to a broad audience of farmers, beekeepers, and backyard gardeners by presenting results at grower meetings and in fact sheets.
Rationale:
Distribution of new research results is a central part of this project as our larger aims include increasing the adoption of sustainable bee management practices and diversifying managed bees used in pollinator-dependent agriculture systems. To accomplish these aims, we attended grower meetings and conferences to distribute educational materials related to our research discoveries. I (Miranda) attended one Utah conference for fruit growers and a blueberry-specific conference in Oregon. I also presented at the annual Orchard Bee Association conference, and I will published a recording of my talk on the Orchard Bee Association website so that an overview of my findings can be disseminated to growers and producers who could not attend.
We have published a fact sheet that outlines the evidence for mason bee use in indoor agriculture. Northern Utah farmers are increasingly dependent on covered or closed plastic tunnels to grow specialty crops, and indoor agriculture is becoming an increasing focus of research groups as conventional agriculture is predicted to be increasingly challenged by climate change (USDA & USDE, 2019). We have observed two of our bee species will readily nest at shelters inside open-sided high tunnels, and our lab has successfully reared O. bruneri in closed cage environments for over 30 years. This is in contrast to honeybees, who struggle to navigate in indoor and covered spaces (Morimoto et al., 2011). There is good reason to promote mason bees as viable indoor pollinators. We have supported these results with 2024's research and delivered a fact sheet based on them, outlining the pollination challenges of high tunnel environments and how different bee options, including mason bees, can meet those challenges.
Materials and Methods:
I (Miranda) attended and presented project findings at the Utah Horticultural Association meeting in February 2025. This annual conference usually garners 70-80 fruit growers from around the state and a rough head count at the event on the day of my presentation was 78. I handed out the Western SARE Outreach Survey after, asking growers about their previous and updated knowledge about mason bee management and their familiarity with the topic.
I also attended and presented my blueberry findings at the Oregon Blueberry Commission’s annual research roundtable meeting in January 2025. This meeting was attended by around 20 growers and researchers.
To share our work online, we will create two fact sheets for disseminating project results. In year 1, we created a fact sheet describing mason bee successes in high-tunnel pollination including two field seasons of study data in strawberry high-tunnels. We also created a one-page fact sheet for our initial blueberry results to present to growers who are participating for another year.
In year 2, we will develop a management strategies that include preliminary data from objective 2. These will published as fact sheets and distributed through Oregon and Utah State University extension social media, most notably the Oregon Bee Atlas Facebook page which has almost 4000 followers. Downloads of the fact sheets can be tracked on the Utah State Extension website, and Oregon State Extension allows for the tracking of website visits or “clicks”. I will monitor the downloads and visits on a twice-annual basis and take additional steps to increase reach at these points (social media outreach, farmers market/ community event flyering, etc.).
Education Objective 3: Publish a peer-reviewed paper on the management potential of the 4 mason bees studied in berry crops.
Rationale:
To ensure the continued work of diversifying pollinator management long-term, the results of this project must be shared in a peer-reviewed journal. Publishing a peer-reviewed paper will help fill knowledge gaps around the behaviors and management potential of each Osmia species, and will encourage future work on the efficacy of mason bees for berry crop pollination. Additionally, we hope that a publication will support the innovations of mason bee producers as they continue to test mason bees outside of the traditional orchard system.
Methods:
We are currently evaluating our results to decide how we would like to format at least one manuscript for publication. We will identify weaknesses and strengths of the work, and have made small changes to improve our methods to ensure that adequate results are obtained this year (2025). After the 2025 field season, we will analyze our data and format a manuscript. We will search for journals and submit a manuscript for publication before March of 2026.
Measuring Participation and Adoption:
We used head counts at our major outreach events (excluding academic research conferences) to estimate total attendance at talks and extrapolated that as the number who likely learned about this project. Additionally, we used surveys received, conversations with attendees, and discussions with event organizers to estimate the distribution of growers/producers, and extension faculty/service providers. Because of some confusion with filling out the survey at events, exact numbers of growers versus service providers is unknown. We did not directly evaluate if participants at these events chose to change any practices, but we held a few informal conversations near the end of this project with our growers to better understand interest in continuing work with solitary pollinators.
Education Objective 1: Increase knowledge about mason bee management and its benefits among farmers and beekeepers by producing two educational videos.
Videos Produced: 1 (research talk)
We discovered through our work that creating traditional outreach videos with management recommendations was immature given the amount of information we still did not understand about the bees of this genus. For instance, a video on material recommendations would be lacking species specific preference information, as bees from our studies responded unpredictably. Instead, we are in the process of publishing one research talk on this work to the Orchard Bee Association (OBA) Youtube channel. This video covers the pollination patterns observed among O. lignaria, O. ribifloris, and O. bruneri and will allow interested parties to access information on potential applications for these species. The Orchard Bee Association has agreed to publish this video publicly and we are currently seeking USDA ARS official approval to publicize our research in this format.
In addition to the research talk, I worked with OBA to further outreach about more basic aspects of mason bee biology and management among growers and the general public. I helped manage the 2024 and 2025 OBA conferences, connecting farmers, bee managers, and students with the latest mason bee management research. I edited two years of conference research talks for the OBA YouTube Channel, developed travel scholarships for student members, campaigned for and successfully nominated candidates for an additional board position to manage Association outreach. Thanks to the work of this additional board position, the OBA has recently produced four informative flyers about mason bees.
Field Days: 2 (+2 educational outreach posters)
| Field Day | head Count (Average from 2 counters) | Predominant category |
| Oregon (Hedgerows and Pollinators) | 52 | Growers |
| Utah (Diversifying Pollination) | 16 | service providers (14) grower (2) |
I created two posters aligned with the original goal of video 2, to connect growers with information on mason bee pollination. Instead of videos, I attended and presented at 2 farmer-farmer field days. One poster presentation took place in Oregon on May 22nd, 2025 at the Hedgerows and Pollinators Workshop, and the other in Utah at the "Diversifying Pollination on Your Farm" field day on June 13th 2025. Both posters held similar information but for mason bees regional to the area. Both posters covreed general information about mason bees and provided region specific species information with the Oregon poster covering O. aglaia, and O. lignaria, while the Utah poster presenting information on O. bruneri and O. lignaria.
Objective 2: Distribute discoveries about berry pollination with mason bees to a broad audience of farmers, beekeepers, and backyard gardeners by presenting results at grower meetings and in fact sheets.
Meetings Attended: 5
OBA - 64: service providers
OBC - 20: 1/2 research, 1/2 grower
USHA - 78: 1:1 roughly grower and service provider
I (Miranda) attended 4 meetings where I presented research on this WSARE research project. The first was the Orchard Bee Association's (OBA) annual conference on September 28th 2024 attended by 64 industry stakeholders (Mostly researchers and bee producers). I gave a 15-minute presentation on the pollen ID results I had collected so far. Attendees seemed excited to learn more about the lesser-managed bees, but had concerns about management potential. As an audience of mainly bee managers, they were acutely aware of how difficult it is to maintain sustainable populations of Osmia lignaria even in abundantly blooming orchards. So while excited about the pollen results, the OBA audience was primarily concerned with addressing the nesting preference questions. I will take this into account for next year, and aim to present primarily on Objective 2 findings.
Next, on January 3rd, 2025 I attended the Oregon Blueberry Commission's research roundtable event and presented my blueberry findings from Oregon in 2024 to an audience of around 20 researchers and farmers. I expected a negative reception to a mainly failed field season with only 1/6 shelters producing pollinating and nesting bees. Instead, researchers and farmers alike were excited to learn about the crop loyalty displayed by Osmia ribifloris and projected interest in further supporting the project in 2025. It seems like blueberry stakeholders are eager for new pollination options, even at the preliminary stages of management where results are inconsistent.
I was invited to attend and present at the Utah State Horticulturalists Association (USHA) meeting later that month on the 31st of January. There, I presented for 20 minutes on mason bee management generally, as well as their effectiveness for pollination of fruit trees and berry crops ( the latter using some of our pollen ID results). This talk was attended by 78 audience members and 48 filled out the WSARE survey. Of the 25 who responded to the question, "In the next year I am likely to adopt one or more of the practices shown", 20 responded "yes" (Figure 14). To the question "In the next year I am likely to use this project to increase my operation's diversifications", 22 attendees answered and 17 answered yes (Figure 15).
While USHA growers seemed excited about the prospect of mason bees' pollination abilities, they were very skeptical when it came to the cost of ~$250 per acre. With high commercial honey bee mortalities in 2025, we are expecting growers to show more interest in alternative managed bees, and hopefully this presentation left them with the resources they need to pursue mason bee purchasing or renting if they want to. Alternatively, it may be wise to target Utah Horticulturalists for involvement in on-farm research, where they can see the benefits of mason bee pollination by participating in a research study, without having to pay for the bees.
I attended the Pacific Branch Entomological Society of America (PBESA) conference and presented a research poster on March 31st, 2025. This poster explained the deeper analytical approach we chose to take when looking at pollen samples from Osmia provisions in strawberries and currants (Figures 4 and 5). During the presenting session, I spoke at length with around 10 academic peers, mainly university researchers, and a one hobby beekeepers. The poster won 1st place in the Master's student competition.
Finally, I presented at the Oregon Blueberry Meeting on Feb 3rd, 2026. This presentation garnered a large (over 100 person) audience, but because of the nature of the conference, not many WSARE surveys were successfully gathered. Through conversations at the ev ent I consulted directly with a large blueberry breeding company, and a grower about using mason bees for blueberry pollination. Beyond this, we estimate the crowd was roughly 40% service providers (including researchers) and 60% producers.
Fact Sheets: 1 public, 2 to participating growers
High tunnel Pollination Fact Sheet: As a part of Education Objective 2, we published a fact sheet on high tunnel pollinators with USU extension services. This fact sheet currently has over 100 downloads.
Blueberry Results One-Pagers: In addition to the planned fact sheets, we composed a one-pager to hand to our growers when we set up blueberry sites again in 2025. This Grower-One-Pager-Blueberry-2024 outlines findings from the 2024 season as well as updated plans that are being implemented with the help of the Oregon Blueberry Commission. We presented these to the 2 farmers we are working with in Oregon this year, and to the 2 USDA collaborators we work with in Oregon. We did this again in 2026 (Grower-One-Pager_-2025-OR-Blueberries-1), presenting it to our participating growers.
Press Articles and Newsletters: 2
I worked with a writer for WSARE to publish a short article about the project, posted February 24th, 2025. This article discusses the research project generally without including many results, but does include some information I have gathered from related literature. I also interviewed for an "Orchard Buzz Spotlight" in the Orchard Bee Associations monthly newsletter, published January 7th, 2025. This spotlight was mainly aimed at personal information, but it did mention two aspect of the project: pollination research in berries and the use of Osmia bruneri in bee management.
Education Objective 3: Publish a peer-reviewed paper on the management potential of the 4 mason bees studied in berry crops.
Low nesting rates with Osmia lignaria and O. ribifloris revealed that much of our management knowledge gained through nesting material preferences is currently masked by a lack of understanding of the landscape level factors at play in the management of Osmia bees, particularly in Utah. Whereas O. bruneri seems amenable to varying straw nesting materials, with not clear story emerging. As such, we pivoted to asking more specific questions targetted at earlier stages of management. For O. bruneri we studied their responses to various overwintering treatments. This work was submitted to the USDA for pre-approval in May and just approved for submission to a journal. We plan to submit to Economic Entomology in advance of the closing date of this grant, July 30th.
Our results on the nesting preferences of O. ribifloris, including nesting material preferences, pollen provisioning, and the effectiveness of the attractant lure, is also written up into manuscript form and ready for publication, but we will finalize this work after the overwintering manuscript has been submitted.
Raspberry pollen collection by O. bruneri in raspberry fields is important information to release, but currently we are not confident in the ability of morphological identification to determine visitation to the crop over other similar pollens present in the environment. We have recently submitted 2025 pollen provision sample extractions to IMR for DNA sequencing to confirm our morphological ID and we will publish our findings as a scientific note if raspberry is identified as the primary pollen within their provisions.
The remaining results are considered largely unpublishable because of the lack of replication between years and sites, with nesting being too variable to make conclusions about material preferences and pollen collection differing between years too much to conclude concrete collecting preferences. However, some results that are not publishable were included in the High Tunnel Pollinator fact sheet as observational data. Most pollen collecting results were also provided to growers through posters at field days and talks at meetings, and some of our "failures" to increase nesting have been used as references in the writing of grant proposals for testing of a different strategies to improve returns.
All in all, despite unexpected nesting behavior by our bees, we were able to produce 1, potentially 2, peer-reviewed journal articles, and will endeavor to produce one scientific note from this work.
Participation Results:
People Who Learned:
We estimated that roughly 130 service providers learned from this work, and around 160 growers. These are rounded down from total estimated counts (135 and 163) as collaborators and certain extension faculty were present at multiple of these events.
Changed Practices:
Because of the nature of most of our outreach, we are not sure how many growers adopted new practices. I do know that one of the participating growers has asked about and then gone on to purchase bees from our bee producer, and the blueberry breeding company I spoke with the blueberry meeting made a decision to use mason bees in 2026, whereas before my talk they were planning on abandoning their solitary bee project. Many people who filled out the WSARE survey implied that they would change practices, but we believe many of these are extension personal expressing interest in incorporating information on mason bee pollination into their curriculums. We therefore estimate that just two growers decided to change their practices, based on our first hand conversations and experience. That being said, we believe that the true number is much higher given the reach of our outreach activities throughout the project duration.