Virginia Orchard IPPM: Native wildflower plot to provide alternative forage, habitat, and refuge for bee pollinators

Progress report for GS23-291

Project Type: Graduate Student
Funds awarded in 2023: $16,500.00
Projected End Date: 08/31/2025
Grant Recipient: Virginia Tech
Region: Southern
State: Virginia
Graduate Student:
Major Professor:
Expand All

Project Information


Honey bees (Apis mellifera L.) and other wild (non-Apis) bees are important pollinators of many fruit, seed, and vegetable crops, including apples [1]. In the US, pollination services of apples are valued at $10.5 million annually [2]. Pesticide usage is essential to many of these agricultural systems and is necessary to feed the world; however, these pesticides negatively impact bees [3, 4]. Therefore, there is a critical need for innovative solutions to bridge the gap between pest and pollinator management.

A native wildflower plot has the potential to provide forage, refuge, and habitat for managed and wild bees that is comparatively free from pesticides [5]. However, less is known about how the presence of this plot may affect bee behavior and health. This study will investigate potential benefits of a native wildflower plot in a fruit crop environment in Winchester, Virginia.

The objectives are to examine the effects of a wildflower plot on honey bee foraging dynamics, pesticide exposure, and non-Apis species richness and abundance by using honey bee waggle dance decoding and GIS mapping, pesticide residue analysis from honey bee-collected pollen, and passive and active field sampling of non-Apis bees. These data will then be compared to previous data for the two years prior to the establishment of the plot in 2021. This will allow us to examine how the native wildflower plot changes these dynamics, which may have significant impacts on Virginia apple best management.

Project Objectives:

Objective 1: Effect of a Wildflower Plot on Apis mellifera Foraging Dynamics and Pesticide Exposure

This objective will investigate the impact of a native wildflower plot on honey bee foraging dynamics, as determined by waggle dance decoding, in a fruit crop environment during apple orchard post-bloom. This objective will concurrently evaluate the impact of the native wildflower plot on levels of pesticide residues from forager-collected pollen. These data will be correlated with our previous (pre-plot) waggle dance spatial data and pesticide residue analyses.


Objective 2: Effect of a Wildflower Plot on non-Apis Species Richness & Abundance

This objective will explore how the establishment of a native wildflower plot influences the species richness and abundance of non-Apis bees in a fruit crop environment in Winchester, VA. Wild bees will be sampled and compared to our previous (pre-plot) sample data to determine how the plot can impact wild bee populations that were likely experiencing similar pesticide exposure.



In recent years, the scientific community has experienced growing concern over the sheer magnitude of insect declines, in part because it represents the larger struggle experienced by much of our wildlife in the face of Anthropocene changes [4]. Additionally, insect declines possess global consequences: beneficial insects such as pollinators are extremely important in the stabilization of global food production and economic security. Therefore, there exists a critical need for the investigation of techniques that alleviate pest pressures without indiscriminately contributing to beneficial insect decline [5]. One potential strategy for mitigating these declines is the integration of native wildflower plots into agricultural environments. Wildflower plots provide diverse pollen and nectar foraging options for many insect species and may also provide refuge from contamination by offering habitat and alternative food sources to “pull” [5] bees away from areas of routine pesticide exposure.

                The objectives proposed here are intended to identify the potential benefits of a wildflower plot to fruit crop growers in Virginia as measured by honey bee foraging dynamics & pollen pesticide residues, and non-Apis bee species richness & abundance. Addressing the objectives in this study will help us to better understand the potential benefits of native wildflower plots on bees. The outcomes of this study could lead to evidence-based recommendations for farmers, land managers, policymakers, and other researchers in the establishment and management of wildflower plots as part of standard IPPM strategies in agricultural fruit crop environments.


Materials and methods:

At the WAREC in Northern Virginia, a ½ acre wildflower plot was established in 2021 through collaboration between the USDA Natural Resources Conservation Service (NRCS), WAREC staff, and the Virginia Department of Agriculture and Consumer Services (VDACS). Wildflower plots provide benefit to bees by providing habitat, dedicated forage, and refuge from pesticide exposure. The WAREC plot is tailored to the needs of this project and specifically to the Shenandoah Valley region of Virginia. Regional specificity in planting is important to increase likelihood of a successful establishment, reduce the need for additional watering or care, and avoid the introduction of non-native invasive species. The native seed mix contains one annual and 21 perennials. By favoring perennials in the mix, the plants will be able to subsist for a few years, depending on the species, and will typically build in vigor with successive years. Eventually, the original species composition will begin to degrade, but this plot is not expected to begin experiencing major fluctuations in annual composition for 5-10 years depending on a range of biotic and abiotic factors. The wildflower seed mix for this plot was selected with the intention of providing blooming flowers throughout the growing season, with a particular focus on the apple post bloom period. The plot is expected to reach peak maturity in the summer of 2024. The WAREC staff manages the wildflower plot and provides general maintenance and upkeep.


Methods for Objective 1

Understanding Apis mellifera forage data requires the decoding and mapping of a unique form of temporo-spatial honey bee communication called the waggle dance. This dance is conducted when a non-reproductive female, known as a worker, returns from her foraging trip and decides to share information about her foraging success. She enters the hive and, while clinging to the comb vertically in near-total darkness, relays coded information in the form of a waggle dance to her sister foragers. The duration of the waggle phase of the dance encodes an amount of distance away from the hive (approximately 750m/1sec dance duration). The dance angle, where vertical “up” on the vertically oriented comb is equated to the direction of the sun, dictates the direction of the resource in relation to the sun (measured as 0o-359o with 0o oriented to the direction of the sun on the horizon). This behavioral communication is visible and can be decoded to indicate a probability distribution of when and where the honey bees are foraging across a landscape [7]. Thousands of individual dancing bees are recorded over a study period and their communicated vectors decoded by hand to provide probability distributions which can be then mapped in ArcGIS to provide an indication of where the bees are foraging in the landscape. Because within hive behavioral correlations are rare, each individual dance is considered an independent replicate in our analysis [7].

This research will be accomplished by installing three glass-walled, honey bee observation hives in an already present and optimized research shed located at WAREC. Recording will occur for one hour/day for three days/week from all three hives the waggle dances performed by returning foragers. Dance data (c. 800 dances) will be decoded and mapped utilizing existing methods [8]. These spatial data will then be analyzed and mapped using ArcGIS Pro to determine where the honey bees are foraging in the ~2km radius centered on the hives, and, if their foraging shifts from the post-bloom apple orchards [6] to the wildflower plot as hypothesized. Data will be collected in May, June, and July of 2024 when the wildflower plot is at its peak.

Concurrently with the video recording, pollen will be collected from returning foragers using wire mesh traps set on the entrances to the observation hives. Pollen will be sorted by color and date, which will then be correlated with plant taxa identity. Representative samples will be sent to Cornell University for pesticide residue analysis using a fee-for-service laboratory. Data will be collected in May, June, and July of 2024 when the wildflower plot is at its peak. This new pesticide data will be compared with data previously collected before the wildflower plot was established and may identify if a wildflower plot is effective in reducing honey bee pesticide exposure.


Methods for Objective 2

Non-Apis bees are not known to possess a visible, decodable communication signal, like the honey bee waggle dance, that would indicate their foraging patterns. Instead, the presence of wild bees is typically recorded by destructively sampling to obtain the highest taxonomic resolution. Some of the larger or more striking bees can be identified to species on sight, but many bees require a microscope for accurate identification within an acceptable degree of certainty. Lethal sampling may seem counter-intuitive for pollinator studies; however, the process appears not to significantly impact species richness or abundance [9]. Sampling methods include active sampling with hand nets or passive sampling with pan or bowl traps, vane traps and, less commonly used for bees, malaise and sticky traps. Blue vane traps have been found to be significantly more effective than other colors of pan or vane traps at measuring bee abundance and species richness: blue vane traps solely accounted for 82.2% of the species collected [10].

The proposed research will double the two years of existing non-Apis bee species richness and abundance data at this location with the total research duration spanning 2021-2024. The gradual establishment of the wildflower plot will potentially influence a change in localized bee species richness and abundance. Therefore, sampling at the WAREC will be done using the same methodologies as previously conducted, including monthly destructive sampling in May, June, and July using blue vane traps, tri-colored bee bowls, and hand netting over a period of 48 hours. Hand netting will be conducted along established transects over a standardized duration. The collected specimens will be cleaned, organized, pinned, and later identified to species. Species richness and abundance will be compared between the pre- and post-wildflower plot establishment periods as the plot comes to its peak in 2024.

Research results and discussion:

Work is still in preparation phase, set to begin fieldwork May of 2024 as per the working plan.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Outreach is still in preparation phase, set to begin outreach Summer of 2025 as per the working plan.

Project Outcomes

Project outcomes:

Work is still in preparation phase, set to begin fieldwork May of 2024 as per the working plan.

Knowledge Gained:

Work is still in preparation phase, set to begin fieldwork May of 2024 as per the working plan.


Work is still in preparation phase, set to begin fieldwork May of 2024 as per the working plan.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.