Our current research projects in the Spivak lab is to promote the health of all bees. Our primary research focus is on honey bees, ranging from basic studies on mechanisms of social immunity and behavior, to applied studies on bee breeding and management.
Honey bees collect resins on their hind legs from a variety of plants and deposit them in the nest cavity where the resins, often mixed with wax, are called propolis. Two graduate students, Mike Simone-Finstrom (PhD 2010) and Renata Borba (PhD 2015) demonstrated that the presence of a propolis envelope on the inner walls of the nest cavity acts as an antimicrobial layer that enshrouds the colony, providing a quantifiable constitutive benefit to bee immune defenses (Simone et al., 2009; Borba et al. 2015). The propolis envelope also directly reduces two diseases of honey bees, chalkbrood and American foulbrood (Simone-Finstrom and Spivak, 2012; Borba and Spivak, in press). Propolis use by honey bees is an example of social immunity, and is a unique example of self-medication, since bees increase resin collection after challenge with a fungal parasite (Simone-Finstrom and Spivak, 2012).
Baased on Mike Wilson’s research (PhD 2013, advised by Dr. Jerry Cohen, Plant Biological Sciences) we are now able to identify the plant source of many honey bee collected resins using metabolomics (Wilson et al., 2013; 2015). Comparing individual resin loads collected from the hind legs of bees with resin collected directly from a variety of trees, we demonstrated that honey bees collected the majority of their resins in our area from cottonwood trees, Populus deltoides. Resin from P. deltoides has antimicrobial activity against the bacterium Paenibacillus larvae and the fungus Ascosphaera apis, the causative agents of American foulbrood and chalkbrood, respectively. The major antimicrobial compounds in these resins has been identified as a series of novel 3-acyl dihydroflavonols (Wilson et al., Patent Appl).
The publications cited above can be downloaded from here. Research on propolis funded primarily by NSF IOS-0717530 and IOS-1256992 to M. Spivak.
Landscapes effects on Honey Bee Health and Native Bee Diversity
Matthew Smart (PhD 2015) and Elaine Evans (PhD 2016), worked on this project (funded by USDA-NIFA 2010-65615-20631: Influence of mid-continent land-use trends on floral diversity and pollen availability to sustain bee health, diversity and ecosystem). This was a collaborative project with Dr. Jeff Pettis of the USDA-ARS Bee Lab in Beltsville, MD, and with Dr. Ned "Chip" Euliss of the USGS in Jamestown, ND.
Matthew Smart quantified the health and survivorship of migratory honey bees colonies located in intensive agricultural environments during the summer months, and moved to California to pollinate almonds over the winter months. Matt modeled colony and individual bee health indices at a critical time points (autumn, prior to overwintering) and related them to eventual spring survival for California almond pollination, over three years. Colony measures that predicted overwintering apiary survival included the amount of pollen collected, brood production, and Varroa destructor mite levels. At the individual bee level, expression of vitellogenin, defensin1, and lysozyme2 were important markers of overwinter survival. He is currently working with Dr. Clint Otto at USGS to test the robustness of these findings in more apiaries over a larger geographic area.
Elaine Evans (PhD candidate) examined the impact of agricultural land use on native bee abundance and diversity in North Dakota. Several land uses within the agricultural matrix were found to support native bee communities. Areas with more wooded land, including stands of flowering trees and shrubs as well as shelter belts, and areas with greater coverage of flowering crops used by bees, such as alfalfa, sunflower, and canola, were associated with greater taxonomic bee diversity. Areas with more semi-natural land (grasslands and CRP) were associated with greater bee functional diversity. Preserving and increasing areas dedicated to these land uses within the agricultural matrix can benefit native bee communities.
In addition, Elaine is surveying Minnesota bees. We currently know very little about the status of most Minnesota native bees. Bee collections are focused on areas with concentrations of historic records. These will be compared to historic records to determine changes in bee communities of the Anoka Sandplain and the Saint Paul-Baldwin Plains and Moraines ecological sub-sections. State-wide efforts to gather information on bees are being organized using volunteers to help us collect data. You can help by participating in the Minnesota Wild Bee Atlas.
Honey bee foraging preferences and native prairie flowers
Morgan Carr-Markell (PhD student) studies honey bee use of native prairie plants as food sources. Recently, movements have grown to help honey bee populations and to restore native prairie ecosystems. It would help to know whether native prairies can attract and benefit non-native honey bees. To identify and assess the most attractive native prairie plants, she collects pollen and honey from colonies placed near large, reconstructed (recently planted) prairies. She looks at the pollen grains in these samples under the microscope and identifies them based on their structure. In addition, she videotapes waggle dances (signals between honey bee foragers about where the best flower patches are) and maps the dances to determine what proportion of the bees’ favorite flower patches is within prairies.
Tech-Transfer Teams: Helping Commercial Beekeepers
Katie Lee, PhD Candidate, heads the Midwest Tech-Transfer Team, a part of the Bee Informed Partnership (beeinformed.org). Tech-Transfer Teams are modeled after crop consultants of the agriculture industry. Tech-Teams help beekeepers monitor diseases and pests, and test potential breeder colonies for disease resistance. Examples of her work are published papers on: A national survey of managed honey bee 2013–2014 annual colony losses in the USA, and Honey bee surveillance: a tool for understanding and improving honey bee health. Her PhD research objectives are to 1) Develop a treatment threshold for Varroa destructor, for commercial Midwest beekeepers; and 2. Investigate causes of queen issues in commercial beekeeper colonies.
Ian Lane (Masters degree, 2016, funded by MN Environmental and Natural Resources Trust Fund) is studying how commercial turf grasses and flowering plants can be combined to create foraging patches for bees in home lawns. As flowering resources are removed from the landscape by human development, new tools are needed to ensure the health of managed and wild bees. Turf grass represents a significant portion of cultivated land in the United States (40 million acres), and is classically devoid of flowers. Investigating new ways of managing and planting turf lawns with flowering plants holds the potential to greatly improve the foraging resources available to bees in highly developed areas.
James Wolfin, new graduate student in 2016, will work in collaboration with Minneapolis Parks and Recreation Board to establish flowers into existing turf lawns in neighborhood parks. These flowering lawn patches will be monitored for establishment and bee visitors, and compared to bees visiting turf lawns that only have the common lawn flower, white clover. The goal is to determine how floral enhancement of urban lawns affects the abundance and richness of bees.
Effects of Neonicotinyl Pesticides on Honey Bees and Bumblebees
Judy Wu-Smart (PhD 2015, Funded by EPA star fellowship; “Sub-lethal effects of neonicotinyl insecticides on honey bee and bumble bee queens and colony development.”) Judy examined adverse sub-lethal effects of neonicotinoid colony exposure on queen honey bee and bumble bee behavior, specifically egg-laying rate and mobility. She also examined the sub-lethal effects of exposure on colony development including brood production, worker foraging rates, and worker hygienic behavior or the ability to detect and remove diseased and or mite-infested brood.
Honey Bee Hygienic Behavior and Bee Breeding
Our (M. Spivak and G. Reuter) primary and long-term goal is to help honey bees and beekeepers reduce the amount of antibiotics and pesticides used in beehives to control diseases and parasitic mites. We have been breeding bees for resistance to these maladies since 1993 with the aim of "getting bees back on their own six feet" to end their reliance on chemical treatments for survival. A reduction in the use of antibiotics and pesticides will reduce operating costs for beekeepers, while ensuring healthy, strong colonies for honey production and pollination, and the purity of honey, wax and other marketable bee products.
Hygienic behavior of honey bees is the main mechanism of resistance to the devastating bacterial disease, American foulbrood, and the fungal disease, chalkbrood. Hygienic bees detect and remove infected brood from the nest before the pathogen becomes infectious. In 1993, we began by breeding a line of honey bees for hygienic behavior with the goal of testing if the behavior is also an effective mechanism of resistance to the parasitic mite, Varroa destructor. Extensive field trials at the University and in collaboration with commercial beekeepers have shown that bees bred for hygienic behavior do detect and remove mite-infested worker brood, and colonies bred for the behavior have reduced mite loads compared to unselected control colonies.
Although our "MN Hygienic" line of bees is sold throughout the U.S., our current emphasis is helping beekeepers and bee breeders select for this and other resistance traits from among their own lines of bees. We are working closely with three Minnesota beekeepers to certify that their stocks are hygienic. Read about it: The future of the MN Hygienic stock of bees is in good hands! (.pdf). We are also working one-on-one with members of the California Bee Breeders Association to help them select for disease and mite-resistance from among their tried-and-true stocks.
Our aim, is to promote genetic diversity, resilience and healthy bees, and we feel that working directly with queen breeders is the best way to accomplish our goal.