Source: OHIO STATE UNIVERSITY submitted to NRP
LANDSCAPE LEGACY AND URBAN AGRICULTURE: UNDERSTANDING THE IMPACT OF HEAVY METAL CONTAMINATION ON POLLINATOR HEALTH AND POLLINATION SERVICES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1012695
Grant No.
2017-67013-26595
Cumulative Award Amt.
$469,220.00
Proposal No.
2016-09305
Multistate No.
(N/A)
Project Start Date
May 15, 2017
Project End Date
May 14, 2021
Grant Year
2017
Program Code
[A1112]- Pests and Beneficial Species in Agricultural Production Systems
Recipient Organization
OHIO STATE UNIVERSITY
1680 MADISON AVENUE
WOOSTER,OH 44691
Performing Department
OARDC Entomology
Non Technical Summary
Cleveland OH's formerly densely-populated inner-city neighborhoods now contain over 27,000 vacant lots as a result of protracted economic decline and the recent home foreclosure crisis. Currently, there are over 250 urban agroecosystems established on formerly vacant land across Cleveland. The sustainability of urban agriculture requires reliable ecosystem services, including pollination. A landscape legacy of heavy metal (HM) soil contamination represents a key threat to pollinators. We propose to study the impact of HM contamination on bee foraging behavior, bumblebee colony health, and pollination. Our work will begin by examining how soil HM contamination influences bee visitation and pollination services of focal crop plants (Objective 1). Next, we will focus on how foraging on contaminated provisions influences colony health, including reproductive potential, nutritional state, immunity, and detoxification (Objective 2). Third, we will track individual pollinators throughout an urban agroecosystem to determine how HM exposure influences their overall foraging patterns and efficiency (Objective 3). Finally, we will determine the weedy flora that provide key resources for pollinators and identify how these plants vary in their concentration of HM (Objective 4). In accomplishing our objectives, we will elucidate the effects of HMs on a vital ecosystem service necessary to attain sustainability and security in urban agriculture.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
30630851130100%
Knowledge Area
306 - Environmental Stress in Animals;

Subject Of Investigation
3085 - Other bees (non-Apis bees) - All bees except Apis cerana; includes Bombas, Alfalfa leaf-cutter;

Field Of Science
1130 - Entomology and acarology;
Goals / Objectives
Objective 1: Determine how heavy metal contamination influences bee visitation and pollination services for key urban agricultural crops. Hypothesis: Heavy metal contamination alters the abundance and diversity of pollinators visiting crop flowers and reduces pollination services.Objective 2: Determine how heavy metal contamination influences colony health of the common eastern bumblebee, Bombus impatiens. Hypothesis 1: Exposure to Heavy metal contaminated nectar sources will reduce reproduction relative to colonies feeding from uncontaminated nectar sources. Hypothesis 2: Exposure to Heavy metal contaminated nectar sources has negative consequences on individual bee health indicators (nutritional state, detoxification gene expression, immunological gene expression).Objective 3: Quantify the impact of heavy metal exposure on the foraging behavior of the common eastern bumblebee, Bombus impatiens.Hypothesis: Workers that consume Heavy metal contaminated food subsequently take fewer foraging trips, spend longer outside of the hive per trip, and return with less pollen. Objective 4: Determine how the composition of pollen and nectar sources available within an urban landscape influence the common eastern bumblebee's, Bombus impatiens, exposure to heavy metals. Hypothesis: Habitat design and management as well as bee foraging preferences influence pollinator exposure to HM contaminants.
Project Methods
Objective 1:Treatment Establishment: We will examine the individual effect of Ba, Cd, Cr, and Pb on pollinator visitation and pollination services using potted sunflower (Helianthus annuus) plants. Sunflowers will be grown in three soil treatments: 1) Control, 2) Median, and 3) Threshold. The Control treatment will consist of plants grown in HM-free potting mix.Video Experimental Design: For each HM, eight plants per contamination treatment will be transported from the greenhouse to a 20 x 30 m mown grass plot on the OARDC campus. The potted plants will be arranged as a randomized complete block design with eight blocks and three treatments (Control, Median and Threshold) per block. The plants will be established by 0800 h. For each HM, we will repeat the experiment on three consecutive days.Measurement of Pollinator Activity: For each experiment, a total of six modified 4-channel security camera systems will monitor pollinator activity at each bloom (n=24). Monitoring will occur across a 6 hr pollination window from 0800 hr to 1400 hr. Following the field experiment, the video will be reviewed, and the time of pollinator arrival (landing on a flower) and departure (leaving the flower) will be recorded as a measure of the amount of time spent at the flower.Measurement of Pollination Services: Pollination services will be measured for the three contamination treatments observed by video (Control, Median, and Threshold) as well as a Bagged Control (flower never exposed to insects) and a Hand-Pollinated Control (complete pollination).Data Analysis: Generalized linear models (GLMs) will be used to determine if HM identity and/or contamination treatment influenced the number, richness, diversity, or longevity of pollinator visits (measured by family, genera or species depending on the resolution of the video).Objective 2: Experimental Design: We will examine how nectar contamination at levels detected in sunflowers grown in the Median or Threshold soil concentrations of Ba, Cd, Cr, and Pb (Objective 1) influence worker survivorship and reproductive potential of bumblebees using field cage experiments. For each HM, nectar contamination at each contamination level will be assessed within a grid of twelve 10 x 10 m screen cages. One bumblebee hive containing 1 queen and 50 workers will be purchased from Koppert Biological Systems, weighed and placed within each cage. Four cages will be randomly assigned to each of the Control, Median, or Threshold treatments. A nectar feeder containing sucrose (Control) or sucrose contaminated with the HM concentration found the flowers of plants grown in the Median or Threshold soil concentration will be added to the appropriate cages and replaced daily to ensure a fresh nectar source.Experimental Procedure and Analysis: Bumblebees will forage for 15 d, after which we will collect and weigh each hive. Samples of five returning foragers, pupae and larva will be amalgamated to quantify the concentration of the HM present within each sample. To determine if forager survivorship, number of larvae, or number of pupae vary among treatments for a given HM we will analyze these data using a GLM with HM treatment as a fixed effect and experiment date as a random effect. In addition, foraging workers will be collected to be analyzed for individual health indicators.Objective 3:Pollinator Data Acquisition System: We have constructed a sampling device that allows the activity of four bumblebee hives to be monitored remotely using RFID technology.Experimental Design: We will examine the impact of the three HMs demonstrated in Objective 2 to have the greatest impact on B. impatiens reproduction and health (referred to below at HM 1-3) using the two pollinator data acquisition systems for a total of eight hives. First, the hives each containing 50 workers and one queen will be obtained from Koppert Biological Systems. Each worker will be removed from the hive, and treated very briefly with CO2 to allow attachment of a RFID tag. The tag will be attached to the dorsal surface of the thorax and have a tracking number unique to that individual. Bees will then be placed back into their hives. After tag attachment, the eight hives will be randomly assigned to one of 7 treatments: 1) Control, 2) HM1 Median, 3) HM1 Threshold, 4) HM 2 Median, 5) HM 2 Threshold, 6) HM 3 Median, 7) HM 3 Threshold. Control hives will be provisioned with a sucrose solution. The HM treatments will receive a sucrose solution contaminated with either the Median or Threshold concentrations of the focal HM's included in Objective 2. Each hive will be fed these sucrose treatments for 7 d.Data Collection: After 7 d of exposure, the sucrose solutions will be removed, and five workers will be removed for HM analysis. The hives then will be loaded into the two data acquisitions systems, and bees will be allowed exit the hives and naturally forage via an outlet tube monitored by an RFID reader. One control hive will be placed within each system, the other six treatments will be assigned at random. The two data acquisition systems will be established at the Kinsman Farm, a six acre research site in Cleveland, OH operated by The Ohio State University, Cuyahoga County Extension. During the experiment, a Linux based supervisory controller will record the number of foraging trips and the length of each foraging trip per individual RFID tagged worker. At the end of 30 d, hives will be returned to the laboratory, weighed, and frozen. Pupae and larvae will be counted and weighed to provide an estimate of colony growth. This experiment will be run twice during the summer of 2019.Data Analysis: Generalized linear models will be used to test the prediction that HM ingestion influences individual foraging behavior via: 1) the number of foraging trips conducted by an individual worker, and 2) the duration of foraging trips per worker. Models will also evaluate the prediction that HM ingestion influences colony health via: 3) the weight of the hive, 4) the number of larvae and pupae at the conclusion of the experiment, and 5) the number of non-returning foragers.Objective 4:Experimental Design: Data will be collected from four urban farms, four vacant lots, and four pocket prairie sites within inner-city neighborhoods engaged in UA. Twice within 2018 (June and August) we will place one bumblebee colony at each site, enclosed in a 1 x 1 m fence to prevent humans or wildlife from disturbing the hive. Pollinators will be allowed to forage for 7 d. Then, twice weekly for the next 3 weeks we will visit each site and between 10:00 and 13:00 h and collect pollen samples from 15 returning workers that will be subsequently released. Pollen from five individuals will be combined for analysis, resulting in 18 samples per site/collection month and a total of 432 samples.Pollen Analysis: A metabarcoding approach using high-throughput sequencing will be taken for taxonomic characterization of mixed pollen samples.Floral HM Analysis: In 2019, following the results of the pollen analysis we will return the same set of sites and collect a total of 8 flowers (2 per site) from up to 20 of the most frequently visited species found in the pollen samples during the June and August 2018 hive exposures. The entire flower head will be dried, ground, and analyzed for HM contamination.Data Analysis: Beyond the analysis of sequencing data described above we will compare the number of taxa visited among habitat using a GLM with habitat treatment as a fixed factor. We will also examine if common-visited plants vary in concentration of HMs using GLMs to determine if foraging patterns influence HM contamination.

Progress 05/15/17 to 05/14/21

Outputs
Target Audience:Our project focused on heavy metal contamination in a legacy city. Our stakeholders included urban farmers, city managers, and non-profit organizations. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Rachel McLaughlin (OSU undergraduate advised by Sivakoff and Gardiner) Awarded a Will C. Hauk Endowment Research Grant. 2017. Effects of Cadmium contamination in soil on pollinators and plants, $2,498 Awarded a College of Agriculture Honors Research Scholarship. 2017. $10,000 Jack Root and Helen Root Entomology Travel Endowment Fund. 2017. $2,000 ESA North Central Branch Student Travel Award. 2018. $200 Sarah Scott (OSU PhD student advised by Mary Gardiner) Inductively Coupled Plasma- Mass Spectrometry & Optical Emission Spectrometry Short Course. Elemental Analysis Using Inductively Coupled Plasma Optical Emission Spectroscopy and Mass Spectroscopy. OSU Trace Elements Research laboratory. 11- 15 March 2019. Columbus, OH. Students presented at the following meetings:? McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services. Ohio Academy of Science Meeting, Bowling Green, OH (Poster) April 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services. Denman Research Forum, Columbus, OH (Poster) April 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services. North Central Branch Entomological Society of America, Middleton, WI. Awarded 2nd Place B.S Student Ten-Minute Paper Competition March 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services. College of Food, Agriculture, and Environmental Sciences Spring Undergraduate Research Forum, Columbus, OH (Poster). Awarded 3rd Place Poster Competition March 2018 Scott, Sarah B. Frances S. Sivakoff, Mary M. Gardiner. The impact of heavy metals on native bees: How the byproducts of urbanization affect the eastern bumblebee, Bombus impatiens. Entomological Society of America; Vancouver, BC, CA. (Oral presentation) November 2018 Scott, Sarah B. Frances S. Sivakoff, Mary M. Gardiner. Bees in the City: The effect of heavy metals on the common bumblebee. Entomological Society of America- North Central Branch; Cincinnati, OH. (Oral presentation). Awarded 2nd place M.S student ten-minute paper competition March 2019 Scott, Sarah B. Frances S. Sivakoff, Mary M. Gardiner. Life in a contaminated habitat: How heavy metals affect the common eastern bumble bee. Entomological Society of America; St. Louis, MO. (Oral presentation). Awarded 1st place PhD student ten-minute paper competition November 2019 Scott, Sarah B. Frances S. Sivakoff, Mary M. Gardiner. Urban chromium concentrations cause changes in bumble bee behavior. Entomological Society of America- North Central Branch; Virtual. (Oral presentation) June 2021 Scott, S.B., F. Sivakoff, M.M. Gardiner. Urban chromium concentrations cause changes in bumble bee behavior. CFAES Annual Research Conference poster competition; Virtual. (Poster) April 2021 Scott, S.B., F. Sivakoff, M.M. Gardiner. The effects of heavy metals on the common eastern bumble bee, Bombus impatiens. CFAES Annual Research Conference poster competition; Virtual. (Poster) Awarded 3rd place M.S. poster competition April 2020 Scott, S.B., F. Sivakoff, M.M. Gardiner. How heavy metal contamination effects fitness in the common eastern bumble bee. Protecting Pollinators in Urban Landscapes; Cincinnati, OH. (Poster) October 2019 Scott, S.B., F. Sivakoff, M.M. Gardiner. Bees in the city: The influence of heavy metal contamina­tion on Bombus impatiens. CFAES poster competition; Colum­bus, OH. (Poster). Awarded 2nd place M.S. poster competition April 2019 How have the results been disseminated to communities of interest? Academic Presentations Gardiner, M.M. The value of urban vacant land for pollinators. Pontifica Universidad Catholica de Chile (presented online, 6/23/20) Gardiner, M.M. Assessing the risks posed by heavy metals to bee health in urban greenspaces. Energy & Environment Program Advisory and Sector Council Meeting. Electric Power Research Institute. (2/24/20) Gardiner, M.M. The balancing act of urban conservation: can vacant land support native pollinators? University of Maryland Student Invited Seminar Speaker. College Park, MD (1/31/20) Gardiner, M.M. Examining the ecology and conservation potential of urban vacant land. OSU-CU Partnership developing agriculture and environmental sciences. Pontifica Universidad Catholica de Chile (7/29/19) Gardiner, M.M. The conservation potential of inner-city vacant land for insects. Department of Entomology Seminar Speaker. University of Manitoba. Winnipeg, Manitoba, Canada. (4/9/19) Gardiner, M.M. The balancing act of urban conservation: Can vacant land support biodiversity and ecosystem services in cities. Keynote Speaker, Landscape Ecology and Nature Conservation. Entomology Congress 2019, German Society of General and Applied Entomology. Halle, Germany (3/12/19) Gardiner, M.M. Vacant lots - A Novel Conservation Habitat? Symposium: Advancing Plant-Herbivore Interactions Through Complementary Approaches and the Blurring of Disciplinary Boundaries. Gordon Research Conference of Plant-Herbivore Interactions. Ventura, CA (2/24/19) ?Gardiner, M.M. The conservation potential of inner-city vacant land for insects. Department of Entomology Student-Invited Seminar Speaker. Cornell University. Ithaca, NY. (1/28/19) Extension Presentations Gardiner, M.M. The balancing act of urban conservation: Can vacant land support native pollinators? Franklin County Master Gardeners Day of Education. Chadwick Arboretum, The Ohio State University. Columbus, OH. (2/1/20) (300 participants) Gardiner, M.M. Dandelion detectives: A youth citizen science program focused on the value of weeds. One Day Insect University. The Ohio State University. Columbus, OH. (10/29/19) (400 participants) Gardiner, M.M. The value of vacant land for urban bee conservation. From Blight to Bight Program. Cleveland Museum of Natural History. Cleveland, OH. (8/19/19) (60 participants) Gardiner, M.M. The value of vacant land for urban bee conservation. Pickaway County Master Gardeners Founders Day Event. Circleville, OH. (6/12/19) (50 participants) Gardiner. M.M. Vacant land for bees: From potential to practical: Vacant Land for Insect Conservation. Stewardship Network of NE Ohio Earth Day Event. Cleveland Museum of Natural History. Cleveland, OH. (4/28/19) (150 participants) Gardiner, M.M. The balancing act of urban conservation: Can vacant land support biodiversity and ecosystem services? The OSU Pollinator Summit. (4/1/19) (300 participants) What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1: Determine how heavy metal contamination influences bee visitation and pollination services for key urban agricultural crops. Hypothesis: Heavy metal contamination alters the abundance and diversity of pollinators visiting crop flowers and reduces pollination services. In summer 2017, we grew sunflowers in the greenhouse in three soil treatments (uncontaminated potting media, and media contaminated with either 10 ppm or 50 ppm Cd). Once mature, these sunflowers were placed into the field and left open to pollination for six hours on three days. Additional flowers from each soil treatment were either hand pollinated (N = 24) or pollinators excluded (N= 24) to compare seed set to those naturally pollinated. Flowers were maintained in the greenhouse until senescence and their resulting seeds counted. Flowers grown in media containing 50 ppm Cd produced significantly fewer seeds than those grown in uncontaminated media. Flowers were also video recorded and the number of pollinator visitors and their visit durations was recorded. Data analysis is in the final stages and we anticipate a manuscript will be submitted for publication in late 2021. Objective 2: Determine how heavy metal contamination influences colony health of the common eastern bumblebee, Bombus impatiens. Hypothesis 1: Exposure to Heavy metal contaminated nectar sources will reduce reproduction relative to colonies feeding from uncontaminated nectar sources. Hypothesis 2: Exposure to Heavy metal contaminated nectar sources has negative consequences on individual bee health indicators (nutritional state, detoxification gene expression, immunological gene expression). In summer 2018 and 2019 we examined how exposure to environmentally relevant concentrations of the metals arsenic, cadmium, chromium, and lead within nectar sources influence bumblebee brood survivorship. Using HM concentrations from bumblebee-collected honey in hives located in Cleveland, OH we developed a replicated tented foraging experiment to measure the fitness effects of these contaminants. We conducted 15 d and 30 d foraging experiments within 13.5 m3 tents, where nectar treatments were compared: arsenic (0.84 mg/L, n=4), cadmium (0.84 mg/L, n=4), chromium (0.76 m/L, n=4), lead (0.265 m/L, n=4), all HM's (n=4) and an uncontaminated control (n=12). Treatments were arranged in a randomized design. Each tent contained a nectar feeder with respective HM concentrations, a pollen feeder, and one colony with approximately 70 workers, allowed to forage ad libitum. After the exposure period, all colonies were weighed, dissected, and brood and adults counted. We found similar brood abundance across treatments, but a significantly higher proportion of dead brood in HM exposed hives. Colonies exposed to a single metal experienced 3 to 4 times higher brood mortality, and colonies exposed to all four test metals were 9 times more likely to contain dead brood. A manuscript is in review in Urban Ecosystems. Objective 3: Quantify the impact of heavy metal exposure on the foraging behavior of the common eastern bumblebee, Bombus impatiens. Hypothesis: Workers that consume Heavy metal contaminated food subsequently take fewer foraging trips, spend longer outside of the hive per trip, and return with less pollen. Over the summers of 2020 and 2021, we are examining how field realistic concentrations of the common urban metals arsenic, cadmium, chromium, lead, and all metals combined influence bumble bee forager behavior using RFID tracking systems. Using paired RFID readers, we designed four units to measure the directionality, foraging duration, and return colony ID for bumble bees marked with unique RFID tags. Per experiment, test bees (n=80) from four naïve Bombus impatiens colonies are tagged with unique RFID tags and returned to their natal colonies. Two colonies are randomly assigned to treatment and fed a sucrose solution with one of the following metal treatments: arsenic (0.84 mg/L, n=3), cadmium (0.84 mg/L, n=3), chromium (0.76 m/L, n=3), lead (0.265 m/L, n=3), all HM's (n=3) and two colonies per experiment are assigned to control and fed uncontaminated sucrose solution for three days. Colonies are deployed and left to forage in field for 14 days. Experiments are ongoing but will be completed by September 2021. Preliminary results for chromium fed colonies show no difference in the number of bees that left each colony, however, treatment bees fed Cr were more likely to enter a non-natal colony at least one time compared to control bees. Individual foraging behavior data is still being analyzed. Data analysis is ongoing and we anticipate a manuscript will be submitted for publication in early 2022. Objective 4: Determine how the composition of pollen and nectar sources available within an urban landscape influence the common eastern bumblebee's, Bombus impatiens, exposure to heavy metals. Hypothesis: Habitat design and management as well as bee foraging preferences influence pollinator exposure to HM contaminants. Pollen collected by Bombus impatiens colonies at 10 sites in and around Cleveland in summer and autumn 2019 has been identified to plant genus using DNA metabarcoding across three plant loci (ITS2, rbcL and trnL). Preliminary analysis indicates that bumble bees were foraging across a diverse range of plant taxa at all sites, including cultivated vegetables and ornamental plants (tomatoes and squash), adventive plants (plantain, clover and goldenrod). Heavy metal analysis of bee-collected pollen was significantly delayed due to COVID19, but pollen metal contamination will be related to both site and dominant plant taxa constituting honey samples when these data become available.

Publications

  • Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Ricke, D.F., C.H. Lin, and R.M. Johnson. 2021. A combination of agrochemicals commonly applied during almond bloom reduces the survival of honey bee (Hymenoptera: Apidae) queens throughout development. Journal of Insect Science, In Review. (cited project support)
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Sivakoff, F.S., S.P. Prajzner, and M.M. Gardiner. 2020. Urban heavy metal contamination limits bumble bee colony growth. Journal of Applied Ecology. DOI 10.1111/1365-2664.13651. (cited project support)
  • Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Scott, S.B., F.S. Sivakoff, and M.M. Gardiner. 2021. Exposure to urban heavy metal contamination diminishes bumble bee colony growth. Urban Ecosystems, In Review. (cited project support)


Progress 05/15/19 to 05/14/20

Outputs
Target Audience:Our project focused on heavy metal contamination in a legacy city. Our stakeholders included urban farmers, city managers, and non-profit organizations. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Rachel McLaughlin (OSU undergraduate advised by Sivakoff and Gardiner) Awarded a Will C. Hauk Endowment Research Grant. 2017. Effects of Cadmium contamination in soil on pollinators and plants, $2,498 Awarded a College of Agriculture Honors Research Scholarship. 2017. $10,000 Jack Root and Helen Root Entomology Travel Endowment Fund. 2017. $2,000 ESA North Central Branch Student Travel Award. 2018. $200 Sarah Scott (OSU PhD student advised by Mary Gardiner) Inductively Coupled Plasma- Mass Spectrometry & Optical Emission Spectrometry Short Course.Elemental Analysis Using Inductively Coupled Plasma Optical Emission Spectroscopy and Mass Spectroscopy. OSU Trace Elements Research laboratory. 11- 15 March 2019. Columbus, OH. Students presented at the following meetings:? McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.Ohio Academy of Science Meeting, Bowling Green, OH (Poster) April 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.Denman Research Forum, Columbus, OH (Poster) April 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.North Central Branch Entomological Society of America, Middleton, WI.Awarded2ndPlace B.S Student Ten-Minute Paper Competition March 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.College of Food, Agriculture, and Environmental Sciences Spring Undergraduate Research Forum, Columbus, OH (Poster).Awarded 3rd Place Poster Competition March 2018 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. The impact of heavy metals on native bees: How the byproducts of urbanization affect the eastern bumblebee, Bombus impatiens. Entomological Society of America; Vancouver, BC, CA. (Oral presentation) November 2018 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. Bees in the City: The effect of heavy metals on the common bumblebee. Entomological Society of America- North Central Branch; Cincinnati, OH. (Oral presentation).Awarded 2nd place M.S student ten-minute paper competition March 2019 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. Life in a contaminated habitat: How heavy metals affect the common eastern bumble bee. Entomological Society of America; St. Louis, MO. (Oral presentation).Awarded 1st place PhD student ten-minute paper competition November 2019 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. Urban chromium concentrations cause changes in bumble bee behavior. Entomological Society of America- North Central Branch; Virtual. (Oral presentation) June 2021 Scott, S.B.,F. Sivakoff, M.M. Gardiner. Urban chromium concentrations cause changes in bumble bee behavior. CFAES Annual Research Conference poster competition; Virtual. (Poster) April 2021 Scott, S.B.,F. Sivakoff, M.M. Gardiner. The effects of heavy metals on the common eastern bumble bee, Bombus impatiens. CFAES Annual Research Conference poster competition; Virtual. (Poster)Awarded 3rd place M.S. poster competition April 2020 Scott, S.B.,F. Sivakoff, M.M. Gardiner. How heavy metal contamination effects fitness in the common eastern bumble bee. Protecting Pollinators in Urban Landscapes; Cincinnati, OH. (Poster) October 2019 Scott, S.B.,F. Sivakoff, M.M. Gardiner. Bees in the city: The influence of heavy metal contamina­tion on Bombus impatiens. CFAES poster competition; Colum­bus, OH. (Poster).Awarded 2nd place M.S. poster competition April 2019 How have the results been disseminated to communities of interest?Academic Presentations Gardiner, M.M.The value of urban vacant land for pollinators. Pontifica Universidad Catholica de Chile (presented online, 6/23/20) Gardiner, M.M.Assessing the risks posed by heavy metals to bee health in urban greenspaces. Energy & Environment Program Advisory and Sector Council Meeting. Electric Power Research Institute. (2/24/20) Gardiner, M.M.The balancing act of urban conservation: can vacant land support native pollinators? University of Maryland Student Invited Seminar Speaker. College Park, MD (1/31/20) Gardiner, M.M.Examining the ecology and conservation potential of urban vacant land. OSU-CU Partnership developing agriculture and environmental sciences. Pontifica Universidad Catholica de Chile (7/29/19) Gardiner, M.M.The conservation potential of inner-city vacant land for insects.Department of Entomology Seminar Speaker. University of Manitoba. Winnipeg, Manitoba, Canada. (4/9/19) Gardiner, M.M.The balancing act of urban conservation: Can vacant land support biodiversity and ecosystem services in cities. Keynote Speaker, Landscape Ecology and Nature Conservation. Entomology Congress 2019, German Society of General and Applied Entomology. Halle, Germany (3/12/19) Gardiner, M.M.Vacant lots - A Novel Conservation Habitat? Symposium: Advancing Plant-Herbivore Interactions Through Complementary Approaches and the Blurring of Disciplinary Boundaries. Gordon Research Conference of Plant-Herbivore Interactions. Ventura, CA (2/24/19) ?Gardiner, M.M.The conservation potential of inner-city vacant land for insects.Department of Entomology Student-Invited Seminar Speaker. Cornell University. Ithaca, NY. (1/28/19) Extension Presentations Gardiner, M.M.The balancing act of urban conservation: Can vacant land support native pollinators?Franklin County Master Gardeners Day of Education. Chadwick Arboretum, The Ohio State University. Columbus, OH. (2/1/20) (300 participants) Gardiner, M.M.Dandelion detectives: A youth citizen science program focused on the value of weeds. One Day Insect University. The Ohio State University. Columbus, OH. (10/29/19) (400 participants) Gardiner, M.M.The value of vacant land for urban bee conservation.From Blight to Bight Program. Cleveland Museum of Natural History. Cleveland, OH. (8/19/19) (60 participants) Gardiner, M.M.The value of vacant land for urban bee conservation.Pickaway County Master Gardeners Founders Day Event. Circleville, OH. (6/12/19) (50 participants) Gardiner. M.M. Vacant land for bees: From potential to practical: Vacant Land for Insect Conservation. Stewardship Network of NE Ohio Earth Day Event. Cleveland Museum of Natural History. Cleveland, OH. (4/28/19) (150 participants) Gardiner, M.M. The balancing act of urban conservation: Can vacant land support biodiversity and ecosystem services? The OSU Pollinator Summit. (4/1/19) (300 participants) What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1: Determine how heavy metal contamination influences bee visitation and pollination services for key urban agricultural crops. Hypothesis: Heavy metal contamination alters the abundance and diversity of pollinators visiting crop flowers and reduces pollination services. In summer 2017, we grew sunflowers in the greenhouse in three soil treatments (uncontaminated potting media, and media contaminated with either 10 ppm or 50 ppm Cd). Once mature, these sunflowers were placed into the field and left open to pollination for six hours on three days. Additional flowers from each soil treatment were either hand pollinated (N = 24) or pollinators excluded (N= 24) to compare seed set to those naturally pollinated. Flowers were maintained in the greenhouse until senescence and their resulting seeds counted. Flowers grown in media containing 50 ppm Cd produced significantly fewer seeds than those grown in uncontaminated media. Flowers were also video recorded and the number of pollinator visitors and their visit durations was recorded. Data analysis is in the final stages and we anticipate a manuscript will be submitted for publication in late 2021. Objective 2: Determine how heavy metal contamination influences colony health of the common eastern bumblebee,Bombus impatiens. Hypothesis 1: Exposure to Heavy metal contaminated nectar sources will reduce reproduction relative to colonies feeding from uncontaminated nectar sources. Hypothesis 2: Exposure to Heavy metal contaminated nectar sources has negative consequences on individual bee health indicators (nutritional state, detoxification gene expression, immunological gene expression). In summer 2018 and 2019 we examined how exposure to environmentally relevant concentrations of the metals arsenic, cadmium, chromium, and lead within nectar sources influence bumblebee brood survivorship. Using HM concentrations from bumblebee-collected honey in hives located in Cleveland, OH we developed a replicated tented foraging experiment to measure the fitness effects of these contaminants. We conducted 15 d and 30 d foraging experiments within 13.5 m3 tents, where nectar treatments were compared: arsenic (0.84 mg/L, n=4), cadmium (0.84 mg/L, n=4), chromium (0.76 m/L, n=4), lead (0.265 m/L, n=4), all HM's (n=4) and an uncontaminated control (n=12). Treatments were arranged in a randomized design. Each tent contained a nectar feeder with respective HM concentrations, a pollen feeder, and one colony with approximately 70 workers, allowed to forage ad libitum. After the exposure period, all colonies were weighed, dissected, and brood and adults counted. We found similar brood abundance across treatments, but a significantly higher proportion of dead brood in HM exposed hives. Colonies exposed to a single metal experienced 3 to 4 times higher brood mortality, and colonies exposed to all four test metals were 9 times more likely to contain dead brood. A manuscript is in review in Urban Ecosystems. Objective 3: Quantify the impact of heavy metal exposure on the foraging behavior of the common eastern bumblebee,Bombus impatiens. Hypothesis: Workers that consume Heavy metal contaminated food subsequently take fewer foraging trips, spend longer outside of the hive per trip, and return with less pollen. Over the summers of 2020 and 2021, we are examining how field realistic concentrations of the common urban metals arsenic, cadmium, chromium, lead, and all metals combined influence bumble bee forager behavior using RFID tracking systems. Using paired RFID readers, we designed four units to measure the directionality, foraging duration, and return colony ID for bumble bees marked with unique RFID tags. Per experiment, test bees (n=80) from four naïve Bombus impatiens colonies are tagged with unique RFID tags and returned to their natal colonies. Two colonies are randomly assigned to treatment and fed a sucrose solution with one of the following metal treatments: arsenic (0.84 mg/L, n=3), cadmium (0.84 mg/L, n=3), chromium (0.76 m/L, n=3), lead (0.265 m/L, n=3), all HM's (n=3) and two colonies per experiment are assigned to control and fed uncontaminated sucrose solution for three days. Colonies are deployed and left to forage in field for 14 days. Experiments are ongoing but will be completed by September 2021. Preliminary results for chromium fed colonies show no difference in the number of bees that left each colony, however, treatment bees fed Cr were more likely to enter a non-natal colony at least one time compared to control bees. Individual foraging behavior data is still being analyzed. Data analysis is ongoing and we anticipate a manuscript will be submitted for publication in early 2022. Objective 4: Determine how the composition of pollen and nectar sources available within an urban landscape influence the common eastern bumblebee's,Bombus impatiens,exposure to heavy metals. Hypothesis: Habitat design and management as well as bee foraging preferences influence pollinator exposure to HM contaminants. Pollen collected byBombus impatienscolonies at 10 sites in and around Cleveland in summer and autumn 2019 has been identified to plant genus using DNA metabarcoding across three plant loci (ITS2,rbcLandtrnL). Preliminary analysis indicates that bumble bees were foraging across a diverse range of plant taxa at all sites, including cultivated vegetables and ornamental plants (tomatoes and squash), adventive plants (plantain, clover and goldenrod). Heavy metal analysis of bee-collected pollen was significantly delayed due to COVID19, but pollen metal contamination will be related to both site and dominant plant taxa constituting honey samples when these data become available.

Publications


    Progress 05/15/18 to 05/14/19

    Outputs
    Target Audience:Our project focused on heavy metal contamination in a legacy city. Our stakeholders included urban farmers, city managers, and non-profit organizations. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Rachel McLaughlin (OSU undergraduate advised by Sivakoff and Gardiner) Awarded a Will C. Hauk Endowment Research Grant. 2017. Effects of Cadmium contamination in soil on pollinators and plants, $2,498 Awarded a College of Agriculture Honors Research Scholarship. 2017. $10,000 Jack Root and Helen Root Entomology Travel Endowment Fund. 2017. $2,000 ESA North Central Branch Student Travel Award. 2018. $200 Sarah Scott (OSU PhD student advised by Mary Gardiner) Inductively Coupled Plasma- Mass Spectrometry & Optical Emission Spectrometry Short Course.Elemental Analysis Using Inductively Coupled Plasma Optical Emission Spectroscopy and Mass Spectroscopy. OSU Trace Elements Research laboratory. 11- 15 March 2019. Columbus, OH. How have the results been disseminated to communities of interest?Students presented at the following meetings:? McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.Ohio Academy of Science Meeting, Bowling Green, OH (Poster) April 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.Denman Research Forum, Columbus, OH (Poster) April 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.North Central Branch Entomological Society of America, Middleton, WI.Awarded2ndPlace B.S Student Ten-Minute Paper Competition March 2018 McLaughlin, RE, Sivakoff, FS, and MM Gardiner. Effects of cadmium contamination in soil on pollination services.College of Food, Agriculture, and Environmental Sciences Spring Undergraduate Research Forum, Columbus, OH (Poster).Awarded 3rd Place Poster Competition March 2018 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. The impact of heavy metals on native bees: How the byproducts of urbanization affect the eastern bumblebee, Bombus impatiens. Entomological Society of America; Vancouver, BC, CA. (Oral presentation) November 2018 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. Bees in the City: The effect of heavy metals on the common bumblebee. Entomological Society of America- North Central Branch; Cincinnati, OH. (Oral presentation).Awarded 2nd place M.S student ten-minute paper competition March 2019 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. Life in a contaminated habitat: How heavy metals affect the common eastern bumble bee. Entomological Society of America; St. Louis, MO. (Oral presentation).Awarded 1st place PhD student ten-minute paper competition November 2019 Scott, Sarah B.Frances S. Sivakoff, Mary M. Gardiner. Urban chromium concentrations cause changes in bumble bee behavior. Entomological Society of America- North Central Branch; Virtual. (Oral presentation) June 2021 Scott, S.B.,F. Sivakoff, M.M. Gardiner. Urban chromium concentrations cause changes in bumble bee behavior. CFAES Annual Research Conference poster competition; Virtual. (Poster) April 2021 Scott, S.B.,F. Sivakoff, M.M. Gardiner. The effects of heavy metals on the common eastern bumble bee, Bombus impatiens. CFAES Annual Research Conference poster competition; Virtual. (Poster)Awarded 3rd place M.S. poster competition April 2020 Scott, S.B.,F. Sivakoff, M.M. Gardiner. How heavy metal contamination effects fitness in the common eastern bumble bee. Protecting Pollinators in Urban Landscapes; Cincinnati, OH. (Poster) October 2019 Scott, S.B.,F. Sivakoff, M.M. Gardiner. Bees in the city: The influence of heavy metal contamina­tion on Bombus impatiens. CFAES poster competition; Colum­bus, OH. (Poster).Awarded 2nd place M.S. poster competition April 2019 Academic Presentations Gardiner, M.M.The value of urban vacant land for pollinators. Pontifica Universidad Catholica de Chile (presented online, 6/23/20) Gardiner, M.M.Assessing the risks posed by heavy metals to bee health in urban greenspaces. Energy & Environment Program Advisory and Sector Council Meeting. Electric Power Research Institute. (2/24/20) Gardiner, M.M.The balancing act of urban conservation: can vacant land support native pollinators? University of Maryland Student Invited Seminar Speaker. College Park, MD (1/31/20) Gardiner, M.M.Examining the ecology and conservation potential of urban vacant land. OSU-CU Partnership developing agriculture and environmental sciences. Pontifica Universidad Catholica de Chile (7/29/19) Gardiner, M.M.The conservation potential of inner-city vacant land for insects.Department of Entomology Seminar Speaker. University of Manitoba. Winnipeg, Manitoba, Canada. (4/9/19) Gardiner, M.M.The balancing act of urban conservation: Can vacant land support biodiversity and ecosystem services in cities. Keynote Speaker, Landscape Ecology and Nature Conservation. Entomology Congress 2019, German Society of General and Applied Entomology. Halle, Germany (3/12/19) Gardiner, M.M.Vacant lots - A Novel Conservation Habitat? Symposium: Advancing Plant-Herbivore Interactions Through Complementary Approaches and the Blurring of Disciplinary Boundaries. Gordon Research Conference of Plant-Herbivore Interactions. Ventura, CA (2/24/19) ?Gardiner, M.M.The conservation potential of inner-city vacant land for insects.Department of Entomology Student-Invited Seminar Speaker. Cornell University. Ithaca, NY. (1/28/19) Extension Presentations Gardiner, M.M.The balancing act of urban conservation: Can vacant land support native pollinators?Franklin County Master Gardeners Day of Education. Chadwick Arboretum, The Ohio State University. Columbus, OH. (2/1/20) (300 participants) Gardiner, M.M.Dandelion detectives: A youth citizen science program focused on the value of weeds. One Day Insect University. The Ohio State University. Columbus, OH. (10/29/19) (400 participants) Gardiner, M.M.The value of vacant land for urban bee conservation.From Blight to Bight Program. Cleveland Museum of Natural History. Cleveland, OH. (8/19/19) (60 participants) Gardiner, M.M.The value of vacant land for urban bee conservation.Pickaway County Master Gardeners Founders Day Event. Circleville, OH. (6/12/19) (50 participants) Gardiner. M.M. Vacant land for bees: From potential to practical: Vacant Land for Insect Conservation. Stewardship Network of NE Ohio Earth Day Event. Cleveland Museum of Natural History. Cleveland, OH. (4/28/19) (150 participants) Gardiner, M.M. The balancing act of urban conservation: Can vacant land support biodiversity and ecosystem services? The OSU Pollinator Summit. (4/1/19) (300 participants) What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Objective 1: Determine how heavy metal contamination influences bee visitation and pollination services for key urban agricultural crops. Hypothesis: Heavy metal contamination alters the abundance and diversity of pollinators visiting crop flowers and reduces pollination services. In summer 2017, we grew sunflowers in the greenhouse in three soil treatments (uncontaminated potting media, and media contaminated with either 10 ppm or 50 ppm Cd). Once mature, these sunflowers were placed into the field and left open to pollination for six hours on three days. Additional flowers from each soil treatment were either hand pollinated (N = 24) or pollinators excluded (N= 24) to compare seed set to those naturally pollinated. Flowers were maintained in the greenhouse until senescence and their resulting seeds counted. Flowers grown in media containing 50 ppm Cd produced significantly fewer seeds than those grown in uncontaminated media. Flowers were also video recorded and the number of pollinator visitors and their visit durations was recorded. Data analysis is in the final stages and we anticipate a manuscript will be submitted for publication in late 2021. Objective 2: Determine how heavy metal contamination influences colony health of the common eastern bumblebee,Bombus impatiens. Hypothesis 1: Exposure to Heavy metal contaminated nectar sources will reduce reproduction relative to colonies feeding from uncontaminated nectar sources. Hypothesis 2: Exposure to Heavy metal contaminated nectar sources has negative consequences on individual bee health indicators (nutritional state, detoxification gene expression, immunological gene expression). In summer 2018 and 2019 we examined how exposure to environmentally relevant concentrations of the metals arsenic, cadmium, chromium, and lead within nectar sources influence bumblebee brood survivorship. Using HM concentrations from bumblebee-collected honey in hives located in Cleveland, OH we developed a replicated tented foraging experiment to measure the fitness effects of these contaminants. We conducted 15 d and 30 d foraging experiments within 13.5 m3 tents, where nectar treatments were compared: arsenic (0.84 mg/L, n=4), cadmium (0.84 mg/L, n=4), chromium (0.76 m/L, n=4), lead (0.265 m/L, n=4), all HM's (n=4) and an uncontaminated control (n=12). Treatments were arranged in a randomized design. Each tent contained a nectar feeder with respective HM concentrations, a pollen feeder, and one colony with approximately 70 workers, allowed to forage ad libitum. After the exposure period, all colonies were weighed, dissected, and brood and adults counted. We found similar brood abundance across treatments, but a significantly higher proportion of dead brood in HM exposed hives. Colonies exposed to a single metal experienced 3 to 4 times higher brood mortality, and colonies exposed to all four test metals were 9 times more likely to contain dead brood. A manuscript is in review in Urban Ecosystems. Objective 3: Quantify the impact of heavy metal exposure on the foraging behavior of the common eastern bumblebee,Bombus impatiens. Hypothesis: Workers that consume Heavy metal contaminated food subsequently take fewer foraging trips, spend longer outside of the hive per trip, and return with less pollen. Over the summers of 2020 and 2021, we are examining how field realistic concentrations of the common urban metals arsenic, cadmium, chromium, lead, and all metals combined influence bumble bee forager behavior using RFID tracking systems. Using paired RFID readers, we designed four units to measure the directionality, foraging duration, and return colony ID for bumble bees marked with unique RFID tags. Per experiment, test bees (n=80) from four naïve Bombus impatiens colonies are tagged with unique RFID tags and returned to their natal colonies. Two colonies are randomly assigned to treatment and fed a sucrose solution with one of the following metal treatments: arsenic (0.84 mg/L, n=3), cadmium (0.84 mg/L, n=3), chromium (0.76 m/L, n=3), lead (0.265 m/L, n=3), all HM's (n=3) and two colonies per experiment are assigned to control and fed uncontaminated sucrose solution for three days. Colonies are deployed and left to forage in field for 14 days. Experiments are ongoing but will be completed by September 2021. Preliminary results for chromium fed colonies show no difference in the number of bees that left each colony, however, treatment bees fed Cr were more likely to enter a non-natal colony at least one time compared to control bees. Individual foraging behavior data is still being analyzed. Data analysis is ongoing and we anticipate a manuscript will be submitted for publication in early 2022. Objective 4: Determine how the composition of pollen and nectar sources available within an urban landscape influence the common eastern bumblebee's,Bombus impatiens,exposure to heavy metals. Hypothesis: Habitat design and management as well as bee foraging preferences influence pollinator exposure to HM contaminants. Pollen collected byBombus impatienscolonies at 10 sites in and around Cleveland in summer and autumn 2019 has been identified to plant genus using DNA metabarcoding across three plant loci (ITS2,rbcLandtrnL). Preliminary analysis indicates that bumble bees were foraging across a diverse range of plant taxa at all sites, including cultivated vegetables and ornamental plants (tomatoes and squash), adventive plants (plantain, clover and goldenrod). Heavy metal analysis of bee-collected pollen was significantly delayed due to COVID19, but pollen metal contamination will be related to both site and dominant plant taxa constituting honey samples when these data become available.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Sivakoff, F.S., S.P. Prajzner, and M.M. Gardiner. 2020. Urban heavy metal contamination limits bumble bee colony growth. Journal of Applied Ecology. DOI 10.1111/1365-2664.13651. (cited project support)
    • Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Scott, S.B., F.S. Sivakoff, and M.M. Gardiner. 2021. Exposure to urban heavy metal contamination diminishes bumble bee colony growth. Urban Ecosystems, In Press. (cited project support)
    • Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Ricke, D.F., C.H. Lin, and R.M. Johnson. 2021. A combination of agrochemicals commonly applied during almond bloom reduces the survival of honey bee (Hymenoptera: Apidae) queens throughout development. Journal of Insect Science, In Review. (cited project support)


    Progress 05/15/17 to 05/14/18

    Outputs
    Target Audience:Our target audeince includes natural resource managers, bee keepers, conservation organizations, and urban farmers. Changes/Problems:Currently we do not need to make any changes to our project plan, but do need additional time to complete our work.Provided that we can get into the field by June 2020 we will be able to complete our work in one year. If not, I am not sure if it will be possible to get another extension, but I will inquire. What opportunities for training and professional development has the project provided?Objective 1: An undergraduate student, Rachel McLaughlin, led the data collection for this objective as part of her undergraduate thesis. Objective 2: A graduate student, Sarah Scott,participated in the Trace Elemental Research Laboratory Inductively Coupled Plasma- Optical Emission Spectrum and Mass Spectroscopy short course in March 2019 to learn how to analyse samples for heavy metal content. A second gradute student, Dylan Ricke, was enrolled to take this traning but it was canceled due to COVID 19. He hopes to take this traning if we are allowed an exentension on this project. How have the results been disseminated to communities of interest?Results from objective 2 have been presented at three conferences in the last year: The Entomological Society of America national meeting in St. Louis, MO (November 2019), the North Central Branch meeting for ESA in Cincinnati, OH (March 2019), and the Protecting Pollinators in Urban Landscape conference in Cincinnati, OH (October 2019). What do you plan to do during the next reporting period to accomplish the goals?Objective 1. As part of this objective we obtained soil testing records for over 300 potential urban agricultural sites (pre-establishment tests) across Cleveland OH. We have created maps illustrating the distribution of Pb across the city and are working on a review article highlighting the potential risks posed by heavy metals to pollinators that will include these maps. Given the COVID 19 situation and our uncertainty of field work in 2020 we are alsoconsidering further analyses and a second paper examining whether heavy metal pollution is clustered within the city, and at all predictable based on location. Objective 2. All research for this objective is complete. We are working on a manuscript detailing our findings. Objective 3. We have built the equipment to track bumble bee foraging and conducted an initial test last summer. In summer of 2020 we plan to conduct all data collection for this objective. We have applied for a permit to conduct this work as OSU is currently only allowing approved work to continue at this time. We are waiting to hear. It is possible that we may have to conduct this work in 2021 if that is at all possible. Objective 4. We have a large number of pollen samples to process in the lab and submit for next generation sequencing.This work will occur as soon as we have access to the laboratory.

    Impacts
    What was accomplished under these goals? Objective 1: We conducted an experiment to determine the effects of cadmium (Cd) contamination on bee visitation to sunflowers and on the resulting seed production in those flowers. We predicted that sunflowers grown in Cd-contaminated soil would receive fewer pollination services than those grown in control soil, resulting in lower seed set. To test this, we grew sunflowers in the greenhouse in three soil treatments (uncontaminated potting media, and media contaminated with either 10 ppm or 50 ppm Cd). Once mature, these sunflowers were placed into the field and left open to pollination for six hours on three days. Additional flowers from each soil treatment were either hand pollinated (N = 24) or pollinators excluded (N= 24) to compare seed set to those naturally pollinated. Flowers were maintained in the greenhouse until senescence and their resulting seeds counted. Flowers grown in media containing 50 ppm Cd produced significantly fewer seeds than those grown in uncontaminated media, however the reduced seed set was not due to a loss of pollinator visitation. Objective 2: Five tented foraging trials were conducted during the 2018 and 2019 summer field seasons to test the effects of heavy metals arsenic, cadmium, chromium, lead and a combination of all on the health and fecundity of Bombus impatiens colonies. Colonies were either exposed to each heavy metal independently or all four heavy metals combined for one 15 day trial and one 30 day trial. Colonies fed one heavy metal had about 3 times higher brood (larvae and pupae) mortality compared to controls, and colonies fed all four test heavy metals had 9 times higher brood mortality compared to control colonies. Objective 3: A microsensys reader and antenna system was purchased in 2018. A test system was designed and built in 2019 that houses 4 separate bumble bee colonies for test trials. A preliminary trial was run in the summer of 2019 to test efficacy of tagging protocol and the system. Objective 4: Pollen was regularly collected from bumble bee colonies placed at 10 sites around Cleveland, OH including seven urban farms and three outlying rural farms over the span of two months (August-September). Pollen was collected from bees returning to the nest using a novel, 3D-printed pollen trap. Honey bee pollen was also collected at two urban sites as a point of comparison. On the final day of pollen-collection, all bumble bee colonies were flash-frozen with liquid nitrogen and stored for metal analysis of bee bodies. Identification of the floral sources of pollen collected by bumble bees will be accomplished with DNA metabarcoding. Pollen samples will also be analyzed for heavy metal content.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2018 Citation: Sivakoff, F.S., S.P. Prajzner, and M.M. Gardiner. 2018 Unique bee community assembly within vacant lots and urban farms results from variation in surrounding urbanization intensity. Sustainability 10: 1926.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Sivakoff, F.S. and M.M. Gardiner. 2017. Soil lead contamination decreases bee flower visit duration at sunflowers. Urban Ecosystems 20: 1221-1228.
    • Type: Journal Articles Status: Awaiting Publication Year Published: 2020 Citation: Sivakoff, F.S., *S.P. Prajzner, and M.M. Gardiner. (in press) Urban heavy metal contamination limits bumble bee colony growth. Journal of Applied Ecology.