Progress 01/01/24 to 12/31/24
Outputs
Target Audience:Our target audience consists of managers, administrators and community participants in the various orchards across the city. At the beginning of the project we determined that the vast majority of our target audience had very little knowledge concerning pollination services and pollinator diversity.Continuous interactions between members of the research team and members of the target audience helped reinforce the relevance of native pollinators and pollinator diversity in relation to pollination services. In our third year of the project we have continued meeting with individual managers as well as carried out various workshops and lectures (at least 10 separate events) at orchards throughout the year in order to educate managers and participants. Our target audience consists of managers, administrators and community participants in the various orchards across the city. Conversations and interactions with orchards' managers revealed that there is significant interest in learning how to increase pollinator populations, especially those of native bees that are more efficient than the European honeybee. During our outreach events (workshops, lectures, etc.), we discussed how to manage the orchard grounds in order to increase nesting habitat for ground and stem nesting bees. We continued to bring specimens, bee ID guides, planting guides and other handouts, wildflower seed packets and multimedia presentations to show the diversity of the native pollinator community. The vast majority of participants in these workshops were the target audience, although at times some high school or college students also attended. Our estimates indicate that we interacted with a minimum of 700 people. In our final year, we plan to summarize our results and recommendations into a series of products geared toward the public, including outreach events at focal sites and pamphlets for broader distribution. For instance, the results of our manipulations concerning the addition of orchard bees should assist in providing managers with some evidence and specifics. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A full day workshop for the entire team was held at Webster University before the field season. Starting with an introduction to the goals of the project, and wrapped up with breakout sessions of smaller groups to train on specific methods, including surveying pollinators diversity, collecting pollen from insects using gel dots, tracking flowering phenology, and video recording bee behavior. During the summer of 2024 we held two workshops for the undergraduate and graduate research assistants. The first, held at University of Missouri, St. Louis was focused on pinning and fluffing the washed insects collected in the spring. The second, held at Webster University, focused on insect identification as students split into specialist groups to identify bees to family and often genus. Graduate students with PIs and an additional two undergraduates worked to identify insects to species. ?Undergraduate students from each of the three universities were highly involved in the project. During the initial field season from March through May, each of the PIs was active in the orchards, mentoring students throughout the process of collecting data. In addition to one senior thesis student, students received course credits and also completed independent projects. Undergraduate students working on the project presented research at national, regional, and local events, such as the Botanical Society of America Conference 2024 (N = 4), Entomological Society of America Conference 2024 (N = 2), International Union for the Study of Social Insects North American Section Meeting (N=1). Maryville Undergraduate Research Symposium 2024 (N = 4), Missouri Native Plant Society Speaker Series 2024 (N = 1), Research Across Disciplines Conference and Mini-RAD Conference at Webster University 2024 (N = 2), and the University of Missouri St Louis Undergraduate Research Symposium and Graduate Research Symposium (N=3) Four graduate students received one-on-one mentoring from their advisors, but were also mentored by the other PIs on the project.One post-baccalaureate tech received mentoring form her advisor as well as by other PIs on the project. How have the results been disseminated to communities of interest?We communicated with each of the orchards that we were working in this year to set up tabling events and informal talks to their communities, for a total of 10 events reaching 705 attendees. We additionally gave talks to beekeepers and other organizations in the region. What do you plan to do during the next reporting period to accomplish the goals?We have received a one-year no-cost extension to finalize data collection addressing parts of both research questions. Specifically, we will continue our experimental treatments of adding bees and nesting habitat to select orchards. During the orchard pollination season we will repeat our data collection for pollen limitation as needed, video surveillance of nest boxes (depending on results as assessed in January 2025), collections and identification of pollinating insects. Across the summer and fall, we will be collecting measures on fruit production and processing the extensive data from the spring field season. We will fine-tune insect identifications to the lowest taxonomic level possible, construct pollinator-tree visitation networks using information compiled from the pollen washes, and begin constructing models of our environmental measures, our spring measures, and fruit production. We will begin compiling results into manuscripts for publication. Specifically, we are currently finalizing analyses for publications regarding (1) the effects of urbanization on pollen fidelity and (2) results from the split-pollinator experiment documenting differences in pollinator quality. We anticipate finalizing an additional 6 papers within 20 months post final data collection.
Impacts
What was accomplished under these goals?
We completed our third season of data collection, and continued the experimental treatments described in our second main objective. We enhanced nesting habitat at six orchards varying in size and urbanization metrics (e.g., impervious surface) by installing bee hotels and raised beds. At six additional locations, we supplemented pollinators by adding 1500 nests/cocoons of commercially available Osmia. The final six locations acted as experimental controls, receiving neither nesting site augmentation nor bee supplementation. ?Pollinator diversity and pollination services. We collected and identified 343 insects (i.e., 71 Andrena spp., 153 Apis mellifera, and a myriad of other bees, flies, and wasps) foraging from flowering fruit trees at the 18 experimental orchards over 24 sampling days. To address Objective 1, we collected more detailed information on pollination services and fruiting success in nine focal sites. Specifically, we quantified the amount of conspecific and heterospecific pollen carried by 338 insects. We documented the phenology of all focal trees and the presence/absence of flowering forbs within the nine focal gardens three times per week for a total of 45 sampling days, and continued to develop the pollen library for pollen load analysis (pollen verified for 250 plant species, including all focal tree species). Our results suggest that total pollen load and the number of pollen types carried do not vary with urbanization. However, the effects of urbanization on pollen fidelity varies from year to year with no effect in 2022, a positive effect in 2023, and a negative effect in 2024. Our working hypothesis is that pollinator species composition and/or the flowering phenology of orchard trees and forbs may be driving these trends. We will continue our analyses in 2025 to tease apart the evidence for each. Pollen limitation and transfer dynamics. To address our objective of determining the extent to which the pollinators in the orchards are providing enough pollination services for the flowers, we continued with a third year pollen limitation experiments. These involve comparing the number of pollen tubes found in the stigmas of open-pollinated flowers to those hand-supplemented with additional pollen across all of the fruiting trees in our sites. For 2024, we collected N = 1400 stigmas from these treatments and recorded the number of pollen tubes for each, as well as imaging all samples. We are still analyzing this data, but to date it indicates which sites are experiencing pollen limitation in 2024 and will be compared to previous years. Preliminary results indicate pollen limitation is potentially related to spatial factors and diversity of resources for bee retention early in the season. In 2023, we saw significant pollen limitation in the smaller urban sites, while in 2022 there were more sites experiencing pollen limitation.. From the stigma data, we are also analyzing the conspecific vs heterospecific pollen load percentages. Our preliminary results across all years show mostly conspecific pollen loads on the stigmas, indicating high fidelity by the pollinators. This data will be compared to the pollen loads collected from the insect sampling. We also continued a more targeted study aimed at comparing the contribution of three different types of pollinators (Apis mellifera, Osmia cornifrons, and Andrena sp.) to the pollination of apple trees. We increased our sample size in 'split-pollinator' experiments, which involve capturing bees on trees and using half of these to pollinate the same tree it was captured on and half to pollinate another tree. This method allows an estimate of the extent to which they are moving between trees; if not, they will be carrying primarily self pollen, and will not do as good a job pollinating the flowers on the same tree. Results continue to show honeybees (A. mellifera) had significant decreases in fruit set in the within-tree relative to between-tree pollinations, while the other bees did not. Thus we can conclude a large portion of pollen limitation of apple trees is due to the fact that honeybees do not move as often between trees, causing them to transfer mostly self pollen. This data has important implications for orchard productivity, as growers frequently import honey bee colonies, incorrectly assuming that this will improve yield. Pollinator behavior and manipulation of added mason bees and nesting sites. In our 2024 field season, we obtained around 270 hours of camcorder footage as well as 280 hours of GoPro footage (approx. 90 hours of which are of the bee boxes). There was a shift in abundance of pollinator groups in that there were more honey bees observed in 2024 compared to both 2022 and 2023. In all years, honey bees still constituted the bulk of pollinator observations. As in 2023, we did not observe more ground-nesting bees at our environmental manipulation sites. Continued video analysis will show how frequently mason bees are utilizing the bee boxes at our pollinator manipulation sites. We have nearly completed analysis of the visitation rates and behaviors of the pollinators in the video footage. Fruit yield. We quantified fruit yield for 324 trees in 18 orchards in the St. Louis region and assessed the quality of 298 fruits from apples, apricots, cherries, paw paws, peaches, pears, persimmons, and plums.
Publications
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Progress 01/01/23 to 12/31/23
Outputs
Target Audience:Our target audience consists of managers, administrators and community participants in the various orchards across the city. At the beginning of the project we determined that the vast majority of our target audience had very little knowledge concerning pollination services and pollinator diversity. In our second year of the project we have continued meeting with individual managers as well as carried out various workshops and lectures (12 separate events) at orchards throughout the year in order to educate managers and participants. In these various workshops, lectures, etc, we brought specimens, bee ID guides, planting guides and other handouts, wildflower seed packets and multimedia presentations to show the diversity of the native pollinator community. The vast majority of participants in these workshops were the target audience, although at times some high school or college students also attended. Our estimates indicate that we interacted with a minimum of 300 people. Continuous interactions between members of the research team and members of the target audience helped reinforce the relevance of native pollinators and pollinator diversity in relation to pollination services. Further conversations and interactions with orchards' managers revealed that there is significant interest in learning how to increase pollinator populations, especially those of native bees that may be more efficient than the European honeybee. We discuss how to manage the orchard grounds in order to increase nesting habitat for digger bees (Family Andrenidae), as well as providing natural wood cavities for twig-nesting bees. The results of our manipulations concerning the addition of blue orchard bees should assist in providing managers with some evidence and specifics. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?A full day workshop for the entire team was held at Webster University before the field season. Starting with an introduction to the goals of the project, and wrapped up with breakout sessions of smaller groups to train on specific methods, including surveying pollinators diversity, collecting pollen from insects using gel dots, tracking flowering phenology, and video recording bee behavior. Undergraduate students from each of the four universities were highly involved in the project. During the initial field season from March through May, each of the PIs was active in the orchards, mentoring students throughout the process of collecting data. In addition to one senior thesis student, students received course credits and also completed independent projects. Undergraduate students working on the project presented research at local events, such as the Maryville Undergraduate Research Symposium 2023, Research Across Disciplines Conference at Webster University 2023, St. Louis Urban Ecology Symposium 2023, Botanical Society of America Conference 2023, Ecological Society of America Conference 2023, and Entomological Society Conference 2023. Graduate student George Todd won a Best Presentation award from the University of Missouri St Louis Graduate Research Symposium. Four graduate students received one-on-one mentoring from their advisors, but were also mentored by the other PIs on the project. Our final event of the year featured team building and presentations from each lab on the results of their portions of the project. We generated great questions and ideas for analyses in the coming years of the project. The feedback from the students was very positive about this event, as they participated with working scientists sharing ideas quickly and enthusiastically. How have the results been disseminated to communities of interest?In February, all of the PIs co-presented at the St. Louis Urban Agriculture Conference, hosted by our collaborating community organization, Seed St. Louis. We talked about the project and our preliminary results, along with advice for supporting native bees in community gardens and orchards. We also talked to many of the hundreds of attendees while staffing a table with collections of bees and information about pollination and native pollinators. Our group hosted an afternoon of the Giving Grove annual conference during August 2023, which was hosted by Seed St. Louis. The attendees of this conference were orchard managers and managers of community organizations, which support small community orchards and other forms of urban agriculture across the United States. Two PIs and two graduate students gave talks on our project, our preliminary results, basic orchard pollination and native bee support, and recommendations based on our preliminary results. We communicated with each of the orchards that we were working in this year to set up tabling events and informal talks to their communities, for a total of 12 events reaching at least 300 attendees. In our nine focal orchards, we participated in both spring planting and fall harvest events such as bonfires and potlucks, as well as a garden and arts festival, a food day, a pollination nesting workshop, nest bulding activities, and an egg hunt. Talks were also given by PIs at Garden Clubs and other community organizations around St. Louis. What do you plan to do during the next reporting period to accomplish the goals?The next grant reporting period will be the final year of our data collection. We will continue our experimental treatments of adding bees and nesting habitat to select orchards. During the orchard pollination season we will repeat our data collection for pollen limitation, video surveillance of pollinators as well as mason bee nest boxes, collections and identification of pollinating insects and the pollen they are carrying. Across the summer and fall, we will be collecting measures on fruit production and processing the extensive data from the spring field season. We will construct pollinator-tree visitation networks using information compiled from the pollen washes, and begin constructing models of our environmental measures, our spring field measures, and fruit production. We will begin compiling results for the manuscripts.
Impacts
What was accomplished under these goals?
We completed our second season of data collection, and during this year we also enacted the experimental treatments described in our second main objective. We enhanced nesting habitat at six orchards varying in size and urbanization metrics (e.g., impervious surface) by installing bee hotels and raised beds. At six additional locations, we supplemented pollinators by adding XX nests/cocoons of commercially available Osmia lignaria. The final six locations acted as experimental controls, receiving neither nesting site augmentation nor bee supplementation. Pollinator diversity and pollination services. We collected and identified 499 insects (i.e., 149 Andrena spp., 130 Apis mellifera, and a myriad of other bees, flies, and wasps) foraging from flowering fruit trees at the 18 experimental orchards over 14 sampling days. To address Objective 1, we collected more detailed information on pollination services and fruiting success in nine focal sites. Specifically, we quantified the amount of conspecific and heterospecific pollen carried by 219 insects. We documented the phenology of all focal trees and the presence/absence of flowering forbs within the nine focal gardens three times per week for a total of 61 sampling days, and continued to develop the pollen library for pollen load analysis (pollen verified for 125 plant species, including all focal tree species). Pollen limitation and transfer dynamics. To address our objective of determining the extent to which the pollinators in the orchards are providing enough pollination services for the flowers, we performed another year's worth of pollen limitation experiments. These involve comparing the number of pollen tubes found in the stigmas of open-pollinated flowers to those hand-supplemented with additional pollen across all of the fruiting trees in our sites. For 2023, we collected N = 1076 stigmas from these treatments and recorded the number of pollen tubes for each, as well as imaging all samples. We are still analyzing this data, but to date it indicates which sites are experiencing pollen limitation in 2023. Preliminary results indicate pollen limitation is potentially related to spatial factors and diversity of resources for bee retention early in the season. From the stigma data, we are also analyzing the conspecific vs heterospecific pollen load percentages. This data will be compared to the pollen loads collected from the insect sampling. We also performed a more targeted study aimed at comparing the contribution of three different types of pollinators (Apis mellifera, Osmia cornifrons, and Andrena sp.) to the pollination of apple trees. Hand-pollination experiments confirmed that these apple trees are pollen limited, not receiving enough natural pollination for maximum fruit yield, and that they are self-incompatible, meaning that they can only set fruits with pollen from other apple tree varieties. We then performed 'split-pollinator' experiments, which involve capturing bees on trees and using half of these to pollinate the same tree it was captured on and half to pollinate another tree. This method allows an estimate of the extent to which they are moving between trees; if not, they will be carrying primarily self pollen, and will not do as good a job pollinating the flowers on the same tree. Results show honeybees (A. mellifera) had significant decreases in fruit set in the within-tree relative to between-tree pollinations, while the other bees did not. Thus we can conclude a large portion of pollen limitation of apple trees is due to the fact that honeybees do not move as often between trees, causing them to transfer mostly self pollen. This data has important implications for orchard productivity, as growers frequently import honey bee colonies, incorrectly assuming that this will improve yield. Pollinator behavior and manipulation of added mason bees and nesting sites. In our 2023 field season, we obtained 240 hours of camcorder footage as well as 280 hours of GoPro footage (56 hours of which are of the bee boxes). There was a shift in abundance of pollinator groups in that there were more small bees and fewer flies observed in 2023 compared to 2022. However, honey bees still constituted the bulk of pollinator observations. Although we did not observe more ground-nesting bees at our environmental manipulation sites, we did observe mason bees utilizing the bee boxes at our pollinator manipulation sites. We will continue to analyze the visitation rates and behaviors of the pollinators in the video footage. Fruit yield. We quantified fruit yield for 236 trees in 18 orchards in the St. Louis region and assessed the quality of 232 fruits from trees in the Rosaceae family (i.e., apples, plums, peaches, and apricots).
Publications
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Progress 01/01/22 to 12/31/22
Outputs
Target Audience:Our target audience consists of managers, administrators and community participants in the various orchards across the city. At the beginning of the project we determined that the vast majority of our target audience had very little knowledge concerning pollination services and pollinator diversity. In order to address that deficiency we met with individual managers as well as carried out various workshops and lectures (13 separate events) at orchards throughout the year in order to educate managers and participants. In these various workshops, lectures, etc, we brought specimens, handouts, and multimedia presentations to show the diversity of the native pollinator community. The vast majority of participants in these workshops were the target audience, although at times some high school or college students also attended. Our estimates indicate that we interacted with a minimum of 170 people. Continuous interactions between members of the research team and members of the target audience helped reinforce the relevance of native pollinators and pollinator diversity in relation to pollination services. ?Further conversations and interactions with orchards' managers revealed that there is significant interest in learning how to increase pollinator populations, especially those of natives bees that are more efficient than the European honeybee. We discuss how to manage the orchard grounds in order to increase nesting habitat for digger bees (Family Andrenidae), as well as providing natural wood cavities for twig-nesting bees. The results of our proposed manipulations concerning the addition of blue orchard bees should assist in providing managers with some evidence and specifics. Managers were also interested in how to increase pollination rates of pawpaws (Asimina triloba), a native fruiting tree that is increasing in popularity among urban orchard growers in the St. Louis region. This species is pollinated by flies, especially those in the blowfly family (Calliphoridae) and the flesh flies (Sarcophagidae). This is a challenge given that the larvae of those flies feed on carrion which in itself is not sanitary and can attract rats. A viable alternative is to do hand pollination given that most urban orchards tend to have between one and five trees. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Three workshops for the team members were conducted before the field season. The first, held at Webster University, focused on collecting pollen from insects using gel dots. A second workshop at Saint Louis University focused on additional methods to collect pollen from insects. The third workshop, held at the University of Missouri, St. Louis, covered all of the background and methods for the undergraduates from the four universities. Undergraduate students from each of the four universities were highly involved in the project. During the initial field season from March through May, each of the PIs was active in the orchards, mentoring students throughout the process of collecting data. In addition to four senior thesis students, students received course credits and also completed independent projects. Undergraduate students working on the project presented research at local events, such as the Maryville Undergraduate Research Symposium 2022, Research Across Disciplines Conference at Webster University, and the international Botany 2022 conference during the summer. Twelve graduate students received one-on-one mentoring on bee identification and taxonomy during the Midwest bee identification workshop held at Saint Louis University. As is typical for graduate students, the four graduate students working on this project received one-on-one mentoring from their advisors, but were also able to be mentored by the other PIs on the project. Our final event of the year featured team building and presentations from each lab on the results of their portions of the project. We generated great questions and ideas for analyses in the coming years of the project. The feedback from the students was very positive about this event, as they participated with working scientists sharing ideas quickly and enthusiastically. How have the results been disseminated to communities of interest?We established and met with our advisory board in August 2022, on which we have representatives from all 10 focal locations. We presented an overall description of the project and opened a dialogue regarding future research initiatives and community engagement. We solicited feedback on implementation of our research in their gardens and worked with representatives from each community garden to devise events that suited their constituents. Following those discussions, we hosted relevant events at each location to introduce ourselves and our work at the gardens with each community. In 2023, we plan to hold similar events during which we will share our results from 2022. We continue to work closely with Dean Gunderson, the Director of Education at Seed St. Louis, to provide meaningful communications with community gardeners. In that vein, we wrote two related stories for their monthly newsletter, which reached 9290 emails and were opened 5851 times, and will be presenting at Seed St. Louis's annual symposium in February 2023. At our next advisory board meeting in Spring 2023, we will share preliminary results of the data collected so far and updated experimental details, etc. ? What do you plan to do during the next reporting period to accomplish the goals?We are on track with the project as originally proposed. In year two we will begin the experimental treatments. In a subset of orchards we will be supplementing bee populations with managed orchard bees, and in a separate subset of orchards we will be adding nesting habitat for both ground and stem nesting bees.
Impacts
What was accomplished under these goals?
In this initial year of our grant, we began collecting as much background data as possible on insect communities and fruiting success in our orchards. Data on the orchards was collected, including soil samples from randomly selected locations at each site, variety information from all the fruiting trees and shrubs, and phenology data for all flowering trees and other plants in the area. A reference collection of pollen was created from both fruiting trees and other flowers in each orchard. Finally, we gathered some overall data on fruiting success across all of our orchards. Fruit weight data for all trees, as well as more detailed data for 297 individual fruits (three fruits per tree were assessed for weight, diameter of core for apples and pears, seed weight, mass fruit appeal) were collected. We gathered video data from each of the focal orchards, with 38 days of collections. These recordings included 153 sets of videos for focal flowers and 131 sets of videos for groupings of flowers. Thus far we are analyzing pollinator behavior in detail from over 400 single flower visits, and have documented around 2000 pollinator visits in total. One goal was to determine the extent to which the pollinators in the orchards are providing enough pollination services for the flowers. To examine this, we performed 'pollen limitation' experiments, comparing the number of pollen tubes found in the stigmas of open-pollinated flowers to those hand-supplemented with additional pollen. Initial results suggest that these trees are not pollen-limited, as the pollen-supplemented flowers received similar amounts of pollen as the open-pollinated ones. We also performed more in-depth experiments on pollination of apple trees, involving a total of 75 flowers in four treatments: open pollination (unbagged, available to all pollinators), self-hand-pollinated (bagged and pollinated with pollen from same tree), no pollination (bagged), outcross-hand-pollinated (bagged and pollinated with pollen from another apple tree). Tracking these treatments through fruiting demonstrate that hand-pollination with outcross pollen results in the greatest fruit yield, with less for open pollination, none for bagged flowers, and only one for self-pollinated flowers. We also collected stigmas from these flowers to determine the number of pollen grains that formed pollen tubes; we have not finished analyzing this data yet. We carried out 26 pollinator sampling events across the nine focal orchards with a total of 189 insects collected while visiting flowers. We have identified a minimum of thirteen bee species, mostly in the Genus Andrena. We also have identified potential pollinators of pawpaw (Asimina triloba), specifically blow flies and flesh flies. Digger bees (Andrena spp.) had the highest prevalence (0.78) and incidence (0.63) among apple and pear visiting insects. This is despite the fact that honeybee hives are present or nearby in five of the nine focal orchards. Other pollinators collected were bees in the Family Halictidae (Lasioglossum sp.) and Family Megachilidae (Megachile sp.). Pollen samples were extracted from over 100 collected insects, half of which have been assessed for pollen load and diversity.
Publications
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