Progress report for OS22-150
Project Information
The chief pollinator of U.S agriculture, the honeybee, is under serious threat. Honeybees face significant colony losses from CCD and other factors. This has significantly increased the cost of renting honeybee hives, which has significantly added to the production costs for farmers and has even endangered the U.S. food supply from a lack of possible pollinators in the future.
The best alternative to honeybees is the native bees already present in the local environment [1, 10-11]. With nearly 3500 species in North America alone, the diversity of different forms, pollen-strategies, and behaviors of native bees provide a wide range of use for agricultural operations.
Thus, the answer to creating a secure and sustainable pollination system in U.S. agriculture is native bees. Past research suggests two main methods to boost native bees in agricultural areas: (a) by providing nesting habitats and (b) by providing additional floral resources (particularly during periods of low food availability). Food resources were targeted by this study, since in the Southeastern U.S. region, the most useful native bees are ground nesting bees that could also nest in the wildflower plots [5]. The targeted ground nesting native bees include mining bees (Genus Andrena), bumble bees (Genus Bombus), and sweat bees (Genera: Augochlorella, Halictus, Lasioglossum).
The main purpose of the proposed study is to assess the benefits of floral enhancement (wildflower plots) to boosting native bee and pollinators in blueberry farms. Studies have shown floral enhancements on the edge of orchards and farms have had a significant effect in recruiting or bringing in more native bees. Now, scientists need to explore what is really going on in the wildflower patches during each major period of the growing season. Specifically, we need to know what is going on during the (1) pre-bloom period, (2) bloom period of the target crop (blueberries), and the (3) post-bloom period/summer dearth period (period of few floral resources).
The results of the proposed project will answer:
(1) Which wildflower species are the best at recruiting native bees pre-bloom and during bloom of the blueberries?
(2) Which wildflower species best support bee populations post-bloom and summer?
With these answers, we can develop ideal wildflower mixes that will boost target native bee abundances by providing the correct wildflower resources. These resources will both increase native bee pollination activities within the farm during the current season and will promote greater offspring production that will lead to high abundances of native bees in subsequent seasons.
Each region of the U.S. varies in farming conditions, bloom times, and variety of native bee species that are available for pollination activities [12]. Regional studies such as the proposed study are essential in gathering accurate information on which wildflower species have the best native bee recruitment characteristics.
Past research on native bees in Georgia have focused on the northern apple producing areas of Georgia. This will be one of the first studies with native bees in central Georgia. Thus, the study’s results will also allow us to compare and contrast native bees’ seasonal diversity and abundance in Northern Georgia verses Central Georgia.
In order to measure whether wildflowers boost native bee abundances and improve agricultural yields, we will perform an on-farm field experiment. The experimental location for the proposed on-farm research project is on the Pinefield Eco Farm in Hephzibah, Georgia. On the farm, we will create six plots of blueberry bushes (3 control and 3 experimental). Figure 1. is a diagram of the plot design at the farm.
Figure 1. A diagram of the plot design at the farm
The experimental plots will consist of 4 rows of blueberry bushes and 1 row of wildflower plants. The wildflower row will be roughly 200 ft2 (50 ft x 4 ft) and will sit in the center, between the two rows of blueberry bushes surrounding it on either side. The control plot will have 4 rows of blueberry bushes. The control plots will be located on the opposite side of the farm in regards to the experimental plots. Experimental plots will be located 200 feet or more from one another.
The wildflower row will be seeded with American Meadows Southeast Pollinator Wildflower Seed Mix. We will add additional seed to the wildflower plots in late December. A total of over 25 wildflower species will be included in the wildflower plot. The wildflowers will bloom at different times ranging from early Spring to Fall.
Objective 1: Measure native bee abundance in experiment blueberry plots with wildflowers vs. control blueberry plots during each of the 3 major periods of the growing season.
In order to gather the data needed to test this objective, we will use a range of sampling methods proven to accurately sample native bee abundance and diversity in North Georgia Apple Orchards, based on a modified Bee Inventory Plot Design [5].
This project will officially begin in April 2022. Year 1 will be a control year. We will set up the 6 blueberry plots. We will perform six monthly samples (April, May, June, July, August) in each plot. (In year 1, two samples will be collected in April - first and last week). In year 2, the experimental year, we will perform 12 samples (2 times a month). Pre-Bloom Sampling (March, 2 samples), Blueberry Bloom (April - May, 3 samples), and Post-Bloom/Summer Floral Dearth (late May - August, 7 samples).
Each of the six plots will be passively sampled using a total of 6 sets of bowl traps (each set consists of 1 UV blue bowl, 1 UV yellow bowl, and 1 white bowl) and 1 malaise trap. Active sampling will be performed by timed sweep netting of 30 minutes in each plot.
In each plot, the bowls will be laid out in an “X” formation from the plot’s site corners. The malaise trap will be place on the edge of the plot in the middle row. For experimental (wildflower) plots, the malaise trap will be placed at the end of the wildflower row.
All bee samples collected will be stored in 95% ethanol and taken back to Georgia Gwinnett College. Professor Schlueter will lead the team of 3-5 GGC undergraduates on sorting the samples and identifying the bees.
Objective 2: Determine which target bee species is present on the specific wildflowers in each of the major periods of the growing season.
There are three major periods of concern: Pre-bloom, Bloom, and Post-Bloom/Summer Dearth (Poor food availability in farms).
During each day of sampling, students and researchers will stake out and observe each flowering wildflower species. Each bee that lands on a targeted wildflower species will be collected. The collected bees will be taken back to GGC for identification.
This data will tell us which bee species is visiting which wildflower species during each major periods of the growing season.
Objective 3: Assess native bee pollination behaviors on wildflowers.
In this objective, video cameras mounted on tripods will be used to measure native bee behaviors at wildflowers and at the blueberry flowers. The use of video cameras allows bees to react normally, without the presence of humans, and frees up students to perform other sampling.
Video cameras will be used in the wildflower patches season long. They will also be used in the blueberry bushes area when the bushes are flowering. Cameras will be set up for 1-hour periods at wildflower and blueberry flowers (when present). Cameras will record bees coming and going to the wildflowers. Genus identification and possibly species identification will be possible from the video camera images. The three goals of this objective are to determine: (1) which bee species is visiting which flower species, (2) the length of time individual bees spend on each flower, and (3) the types of interactions that occurs (e.g. buzz pollination, full body submersion into flower, etc.).
Objective 4: Assess the effect native bee pollination has on boosting blueberry crop quality and overall yield.
Later in the season, several bushes in each of the plots (Control and Experimental) will be assessed for their overall blueberry yield. We will examine two factors: (1) overall fruit quality (based on average size (width) of the berry) and (2) the average amount of berries produced by each bush (numbers and weight).
The data gathered in the above methods and objectives will allow us to make conclusions about which wildflowers have the best characteristics for recruiting native bees to agriculture areas. Conclusions on the benefits on native bee pollination and the use of wildflowers plots can also be made based on their overall impact in boosting crop quality and amount.
Cooperators
- (Researcher)
Research
Annual Report (Year 1)
(April 2022-March 2023) "Control year"
Sampling of the native bees (Objective 1)
During the first year of the study, there were 8 bee sampling events at the blueberry farm. The sampling events were on: March 22, April 22, May 10, May 28, June 10, June 17, July 8, and September 24.
Each of the six plots was passively sampled using a total of 6 sets of bowl traps (each set consists of 1 UV blue bowl, 1 UV yellow bowl, and 1 white bowl) and 1 malaise trap. Active sampling was performed by timed sweep netting of 30 minutes in each plot.
Observation of bee behaviors at the blueberry flowers and other wildflowers in the plots (Objectives 2 and 3)
During the first year of the study, we observed and recorded bee activity at various blueberry and wildflowers.
Sample of blueberry fruit in the experimental area (plots 1-3) and the control area (plots 4-6) (Objective 4)
During the first year of the study, we compared and contrasted the blueberry fruit produced in the experimental area (plots 1-3) and the control area (plots 4-6). In year 2 (2023), the experimental plot will have wildflowers added. A selection of wildflower seed was planted in the plots in January 2023.
Sampling of the native bees (Objective 1)
During the first year of the study (2022), there were 8 bee sampling events at the blueberry farm. We collected 549 bees and 52 hoverflies at the farm on the eight-sampling day. The most numerous Genera were the Lasioglossum (83%), Anthidium (7%), Halictus (3%), and Habropoda (2%) (see table 1). Small sweat bees were the most dominant bee at the blueberry farm.
One unusual observation in the native bee collection was the absence of the mining bees (Genus Andrena). Mining bees are the most important and most numerous native pollinators in North Georgia. It is hypothesized that the sandy soils in the Augusta region (part of the coastal plain) is poor habitat for mining bees. North Georgia, in contrast, has high clay content soil (Piedmont region of Georgia)
New questions: Which native bee group(s) will replace the mining bees, who dominate pollination in North Georgia? Can the small sweat bees, which are the dominate native bee group in this sandy soil area, be recruited in large enough numbers needed to effectively pollinate the blueberry bushes on the farm?
In addition to native bees collected at the farm, we also collected hoverflies. Hoverflies are known to be effective pollinators. Perhaps, hoverflies could play a large(er) pollination role in the blueberry flowers, particularly with some major bee groups (e.g. Andrena) being absent in this sandy soil habitat.
We collected 52 hoverflies at the farm. Bees outnumbered hoverflies by more than 10 to 1. The majority of hoverflies were collected in yellow pan traps. Yellow is the best color to attract hoverflies. The genus Toxomerus was the most common group collected, representing 43 of the 52 (83%) hoverflies collected. The 2 most common species were Toxomerus germinates and T. marginatus.
Table 1. Year 1 - Bee Collection Results at the Blueberry Farm
Observation of bee behaviors at the blueberry flowers and wildflowers (Objectives 2 and 3)
During the first year of the study, we observed and recorded bee activity at various blueberry and wildflowers. The two most common groups to visit the blueberry flowers and the wildflowers were the Southeastern blueberry bee (Habropoda laboriosa) and sweat bees (Genus Lasioglossum). Other bee groups were poorly represented.
On the blueberry flowers, several different bee species were observed to interact with the blueberry flowers (late March thru early April). The Southeastern blueberry bee and sweat bees were the most common bees observed. Preliminary results indicated that the Southeastern blueberry bee spent more than twice the time at each flower compared to the sweat bees.
On the wildflowers, the Southeastern Blueberry bee was most often seen on white flowers. They were also seen on yellow flowers. At the farm, the Southeastern blueberry bee was rarely observed interacting with wildflowers and did not appear in samples after May.
On the wildflowers, the sweat bees were most often seen on yellow flowers. However, they were also observed on white and purple/blue flowers as well. Sweat bees were abundant throughout the farm sampling (March – September).
Sample of blueberry fruit in the experimental area (plots 1-3) and the control area (plots 4-6) (Objective 4)
During the first year of the study, we compared and contrasted the blueberry fruit produced in the experimental area (plots 1-3) and the control area (plots 4-6). In year 2 (2023), the experimental plot will have wildflowers added.
In year one (2022) in the month of June, we selected 6 bushes in the experimental area (2 bushes per plot, plots 1-3) and 6 bushes in the control areas (2 bushes per plot, plots 4-6). The bushes in the control plot yielded an average of 5.4 grams of blueberries per bush compared to an average of 4.1 grams of blueberries per bush in the experimental plot. A t-test indicated that the values were not significantly different. Blueberries from control plot bushes yielded an average length of 4.27 mm compared to experimental plot blueberries with an average of 5.11 mm. A t-test indicated that the values were not significantly different. These results indicate similar yield in the control and experimental area blueberry bushes.
This is an important result that shows similar results in bushes before the wildflowers were introduced. Adult plants were introduced in plots 1-3 (the experimental area) in the summer of 2022 and wildflower seed was planted in January of 2023. No wildflowers were introduced in the control area.
Educational & Outreach Activities
Participation Summary:
In addition to performing on-farm research at the blueberry farm, I have involved over 20 GGC students in performing agricultural research. I created a new course at Georgia Gwinnett College (BIOL 4570 Experimental Methods – Surveying bee diversity and abundance in target environment).
This class is designed for senior biology majors to give them practical experience performing field research. Students traveled to the blueberry farm and perform various experiments. Experiments focused on insects (bees and hoverflies) and also on blueberry yield estimates. Students got a chance to talk with farmers, learned about some of the challenges of farming, and got to hear unique insights about growing blueberries and other crops in Georgia. This course was offered in the Summer 2022 and Spring 2023 semesters and will be offered in the Summer 2023 semester as well.
Learning Outcomes
Sustainable Agriculture
Use Native Bees (Alternative for pollination of crops)
Project Outcomes
This is the first year of the project.
Zane Redman has adopted the practice of planting wildflowers of the edges of his blueberry bush plot, in order to recruit more native bees.
It is hypothesized that more native bees recruited will boost blueberry yield.