Progress report for OW20-359
The proposed project focuses on exploring how to increase the number and the quality of colonies involved in agricultural production in 2 states, Arizona and Hawaii. The managed bees in Arizona form part of the migratory pool of pollinators that services almond growers in California, and the Hawaii bees are involved in local cucurbit production, as well as, providing additional services to the macadamia growers.
- Objective 1- Improve the health of colonies that will provide pollination services
- Test the impact of feeding supplements (carbohydrate based, protein based, and phytochemical based supplements) on the overall health of the treated colonies in AZ and HI.
- Health parameters that we will recorded will be quantifiable measures of viral titers of Deformed Wing Virus, Nosema spores, and Varroa mite numbers, as well as honey production and colony bee population estimates.
- Objective 2- Incorporate colonies that would be destroyed into the pool of manageable honey bee colonies
- Determine what is the most suitable timing for effective re-queening with European Honeybees (EHB), converting the swarms of Africanized bees (AHB) into usable colonies for pollination and honey production.
- AHB are less susceptible to mites, consequently they need less frequent treatments. In our project we will examine when is the most productive time to make the switch to EHB queens to promote colony growth, while balancing the use of the natural mite defense of AHB for as long as possible in the apiary.
- Objective 3- Examine the variation in mite and disease resistance present in the feral population of AZ honey bees
- Collect data on the bee genetics, document possible mite resistance, and examine the levels and strains of viral diseases in the wild caught bees in AZ.
- The findings will help best integrate the existing honey bee genetics, with management strategies. Assessing sources of resistance and variability should be considered as part of the potential management along with the introduction of EHB queens.
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Parallel work on supplemental feeding and bee health will be conducted on Oahu (HI) and Tucson (AZ). The Oahu sites include, Waimanalo Research Station from the University of Hawaii, and private farms in Waimanalo, Waianae, and Kunia. The Arizona site includes apiaries in state land designated for ranching.
Objective 1-- Improve the health of colonies that will provide pollination services
To achieve this objective we will gather information about the natural resources available to the colonies throughout the year. Fresh pollen collections from each hive will obtained using pollen traps for every trimester. Pollen will be oven dried and weighed to establish a rate of collection/ amount of time trap was in place. A fraction of the pollen collected will be analyzed for levels of protein and fat. The level of abscisic acid (ABA), an important phytochemical for bee health, will also be examined through gas chromatography. Honey storage levels will be quantified using digital photography of hive frames and analyzed at the lab via computer.
Second-The effect of supplemental feeding (syrup with ABA, and pollen patties) to colonies during dearth periods (mainly winter months) will be examined by comparing brood and honey areas in control and treated colonies, as well as through the collection of adult bee samples for molecular detection of Deformed Wing Virus and microscopic quantification of the intestinal parasite Nosema sp, to test the idea that well fed colonies will have a more robust immune system thus a lower disease level.
Objective 2- Test the timing and effectiveness of re-queening with European Honeybees the swarms of Africanized bees (AHB)
Africanized honeybees are not well suited to large-scale agriculture due in part to their more defensive behaviors, but also because of their tendency to swarm more frequently, which significantly reduces the work force of the colony. However, killing or “pinching” a AHB queen and subsequent replacement with an already inseminated EHB queen provides a way to harness the colony and transform its genetics. Caution and experience is needed to ensure the workers accept their new queen, but once that queen has been accepted, the new generation will be fully European genetically. We will test when is the best season to replace the AHB to ensure maximum acceptance rate of the new queens. Two sources of queens will be used (HI and NM), to examine if acceptance is influenced by the queen origin. In both states we will keep track of queens to examine queen effects, treatment, and to investigate if there is an interaction effect, consequently, all queens will be number and color-coded with tags on their thorax.
Objective 3- Collect data on the genetics and possible mite resistance or variable levels of viral diseases in the wild caught bees in AZ.
The wild swarms collected in Arizona provide a great opportunity to understand the dynamics of honey bee populations. The AHB have displaced the feral EHB, as well as other native bees that used rodent burrows, such as the Desert Bumblebee. In the outskirts of Tucson and in the open ranges of the desert surrounding Tucson the bee populations survive under much harsher conditions than in the city, however, there is no data on the genetic admixtures of AHB vs EHB present. With the looming climate changes and the increase disease pressure on pollinators, exploring natural resistance in isolated populations of plants and animals is an important and urgent task.
A recent study by Kevill et al, (2019) revealed that in Eastern California and Southern New Mexico a rare strain of the deadly Deformed Wing Virus (DWV), the so-called Type C, was present. These were the only two sites where this viral strain appeared in significant levels in the whole US. Arizona, although geographically found in between the 2 hot spots reported, was not included in this study. By examining the bees in AZ we could answer whether Type C is linked to either geography, climate and/or the genetic race of the bees. Because we will be monitoring individual colonies for long time we can also document mortality in relation to mite levels, viral titers, strain of DWV. The molecular work will be conducted in HI and DWV detection and strain identification can be determined through extraction of RNA and the use of the already available DWV PCR primers for the 3 master variants (A, B, and C) and viral titers will be examined using qPCR (real time polymerase chain reaction) techniques.
A Linear Mixed Model Effects will help to examine longitudinal evaluations and multiple observations on the same colony. The statistical analysis selected will help us better understand the link between the colony identity, genetics, time of the year, prevalence and virulence of this disease in treated (supplemental feeding) versus control colonies (no supplemental feeding).
Educational & Outreach Activities
The proposed project is ongoing, and objectives are being reached despite the severe drought and heat waves experienced in the area. The state of Arizona has been under a severe drought since 2020 and the bees entered the winter of 2020-2021 with a deficit of natural forage and much reduced winter rains. As a result of the low precipitation, the Spring and Summer of 2021 did not produce the typical blooming, rather, the area entered a category USDA D4 drought = exceptional. I will include in this report the effects of the large-scale climatic event and the modifications that were made to the project as a result of the unforeseeable conditions.
Objective 1- The testing feeding supplements The extreme drought and heat scorched the natural forage of the desert site, consequently we provide survival food for the colonies but were unable to compare diet versus no supplement, since that would have meant death for the colonies with no-supplement.
There were 3 types of diets provided, sugar syrup as a source of carbohydrates, commercial bought pollen patties, and our own formula of home-made pollen patty. The success or preference of the colonies on the supplements was noted, but most importantly, was the discovery of the subtle changes in food preference during different parts of the year and how water availability affected the bees’ preferences of some formulas. This finding led to a whole new segment of the project which I will explain later in the report.
Objective 2- Incorporate colonies into the manageable pool of honeybees
To achieve this objective, we knew we had to overcome the well-recognized difficulties of requeening an Africanized colony with a queen of European origin. We have so far achieved this with 3 different batches of queens, one set from New Mexico and 2 from Hawaii.
The process of requeening AHB requires more time and planning than the re-queening of EHB colonies. The wild bees from AZ, which are heavily Africanized required about a week without a queen before a new queen could be added to the hive, compared to hours for an European colony. This more gradual introduction and repeated checks of the AHB colony to destroy multiple queen cells is absolutely necessary.
With our technique the acceptance of the new queens was surprisingly high; we had a 93% acceptance rate with the New Mexico queens (n=25 queens), and 72% with the Hawaii queens (n=21 queens). The difference between these 2 groups could be due to several reasons: A-we drove to NM to bring the queens directly to Arizona, the Hawaii queens were shipped, B-the time of the year in which the splits were created, and the queens introduced. The NM queens were introduced earlier in 2020 when the drought had not impacted the colonies as much.
The obvious next step, introducing the colonies to farms in 2021 was not possible as ranchers, growers, and beekeepers were struggling to keep their crops and animals alive through the record heat and drought. We lost some of the splits with new queens not due to rejection but simply because the climate was very harsh on small colonies independent of queen origin. However, we are working towards the possible inclusion of the bees in raspberry production in California.
Objective 3 – Collect genetic data on the colonies.
During this study, we have been recording if the colonies need Varroa mite treatment and examined the genetic background of a portion of the colonies. Most recently, we began an additional collaboration with Dr. Brock Harpur, from Purdue University, to examine in depth the genetic origins of the feral bees in AZ. We are awaiting results of a full genomic analysis on 50 colonies which would provide important and novel information on the feral bees in the Southwest. Dr. Harpur is an expert in honeybee genetics and his lab works towards incorporating new molecular technologies to assist beekeepers and the agricultural industry make informed decisions.
Additional research avenues:
The extreme climatic conditions were hard to ignore, but rather than just surviving the challenge, we decided to dig further into the situation and how heat and extremely low relative humidity affect the bees and their ability to keep brood at a constant temperature and maintain humidity inside the nest. We utilized internal and external sensors and obtain a uniquely detailed data on the physiological challenges the colonies experience and how water foraging may impact the dynamics, growth and survival of the colonies. This data will be analyzed and submitted to a peer-reviewed journal by the end of the year. A producer friendly version will also be made averrable as an extension handout and video (see educational activities)
We have given online talks to California, Arizona, and Hawaii beekeeper organizations, in addition we have participated in 2 workshops on Invasive Species in Hawaii, where the Africanized bees is not present. The workshops from the Hawaii Invasive Species Council includes members of the Hawaii Department of Agriculture from 5 islands, which allow us to reach a broad audience of professionals.
We have assisted local beekeepers in Tucson Arizona with management advice, and help applying for USDA recovery funds approved due to drought.
We are currently developing an educational video based on the challenges for beekeepers and their bees under the drought conditions experienced these past 2 years. Filming is complete, a voice over track exists, and we are editing the video.
The unexpected climatic stresses that affected honeybee colonies in 2020-2021 in AZ provided an opportunity to explore physiological adaptations of managed bees under heat stress and severe drought. The data collected, which is being analyzed and described for publication is rare and important for future management of agricultural pollinators.
The extreme climatic conditions also allowed us to experiment with novel ways of providing supplemental forage to bees.
The suite of behavioral observations we have collected will be paired with genetic information that can help us understand how wild populations of bees across the southwest may hold the key to some important health traits that may be lacking and could benefit managed bee populations.
We established a technique for successfully re-queening AHB, and we will continue to test and examine the nuances of these queen exchanges between AHB and EHB colonies, which is a serious concern in Southern California where almonds are produced.