A "Bee-g" Question: How do Honey Bees and Native Bees Interact?

Image: A honey bee and a native bee forage on the same floral resource in the Cache Valley, Utah. Utah is home to about 900 species of native bees, and 28,000 commercial honey bee colonies.

Access to clean, nutritious forage is essential for all bees, and as bee forage is declining each year in the USA, the number of native bees and managed bees are also declining. 75 years ago there were nearly twice as many honey bee colonies in the US, and more than half the native bee species assessed seem to be in decline.   

Less habitat and forage availability increases potential for resource competition, and as bee health concerns are top of mind, many questions arise about whether bees create pathogen pressure by transmitting diseases while foraging. Concerns about native bee vulnerability and habitat scarcity have brought efforts to exclude honey bees from some forage and pastures. Such policies could have far-reaching effects on an already strained beekeeping industry, and also pits bees against each other. 

Project Apis m. and Costco USA are supporting a multi-year project to study honey bee and native bee interactions, to increase the science in this area and also learn more about how to improve and manage habitat for the benefit of many bee species.

​We recently visited the project at the USDA-ARS Native Bee Lab in Logan, Utah.  This lab, which is home to both Apis (honey bee) and non-Apis experts, is uniquely able to study several bee species closely in a variety of lab and field conditions. This is a very complex project involving technology to measure and track several species of bees’ behaviors and reproduction, enclosures with engineered habitats to evaluate plant species’ use by various pollinators, and field sites characterized with and without managed honey bees.

Image: Principal investigator and USDA-ARS Research Leader at the Logan Bee Lab, Diana Cox-Foster, PAm Executive Director Danielle Downey, Commercial Beekeeper and Honey Producer Darren Cox, and other USDA-ARS researchers talk outside of screen houses containing honey bees and native bees at the USDA-ARS Logan Native Bee Lab in Logan, Utah.

This project aims to study interactions between bee species and measures of health:

• competition and behavioral changes (including foraging behavior)
• pathogen transmission and symptoms or effects of pathogens in different species
• overall health and strength of bees  
• brood rearing and reproduction
• forage utilization, both in natural and engineered habitat

 
Using three different locations and trials, a variety of bee species and floral settings are being observed.  In one trial, several large screen houses contain different combinations of bee species and floral resources, which are monitored using cameras, x-rays and traffic gates.

Image: Drs. Lindsie McCabe, Jonathan Koch, and Diana Cox-Foster look through a screen containing multiple species of bees. Each screen house contains a combination of bee species and 10 species of blooming plants.

Images: Each screen house is marked with the species contained within

Images: (L) Lab Technicians use a borescope camera to monitor a bumble bee colony. Pathogens are collected from each bumble bee colony using a removable acetate sheet that catches frass (bee poop). (R) Lab Technician Aletia James adjusts a GoPro on a mason bee nesting box inside of a screen house. Mason bee nests are x-rayed daily to track nesting cells.

​A second trial is conducted at a screen house containing mason bees with a honey bee colony located outside of the screen. The honey bees are allowed limited access to the screen house so data can be collected in the same environment with and without the presence of honey bees.

Images: (L) Researchers talk outside of the large screen house containing mason bees, with a honey bee colony placed outside (R) A specially designed pipe allows researchers to choose to exclude honey bees from the screen house, or to direct them into the screen house for observation and analysis.

In a third trial, honey bee, bumble bee and mason bees are placed on public lands in the Cache Valley in a grazing and recreational area. In addition to monitoring the bees, transects are surveyed for floral resources, and native bee surveys are conducted. These locations have a long history tracked by Darren Cox, of Cox Honeyland, who helped conceive the project, and provided the honey bees and locations for this trial. 

Images: (L) Dr. Diana Cox Foster, Danielle Downey, Darren Cox, Dr. Jonathan Koch and Dr. Lindsie McCabe at a field location. On the left are bumble bee colonies, and in the background are honey bee colonies. (R) The orange flag marks the corner of a transect that is surveyed for floral resources, native bees, and bee activity.

Images: Dr. Lindsie McCabe points out a mason bee nesting block at the field site location.

Images: Dr. Lindsie McCabe, PAm Operations Director Patty Shreve, and Dr. Diana Cox-Foster observe native bees at the field site

​An unexpected discovery in the first year of field trials was that almost all of the managed bumble bee colonies (Bombus huntii) were parasitized and killed by a kleptoparasitic bumble bee, Bombus insolaris. This discovery led to a publication and the knowledge that  excluders can be used to protect managed bumble bee colonies from parasitism by Bombus insolaris. 

Image: (L) A Bombus huntii worker enters a research colony through an excluder designed to keep out Bombus insolaris. (R) A Bombus insolaris queen is raised in the lab for research purposes. These bumble bees lack corbicula (pollen baskets) and are unable to collect their own resources; they must rely on stolen resources from other Bombus species.

The robust presence of Bombus insolaris is thought to reflect an equally robust population of other bumble bee species in the area. This, along with genetic evidence, could suggest the honey bee colonies present in the area did not negatively impact the success of the native bees in the area, though as the authors state in the publication, more research is needed to fully understand the relationship between honey bees and native bees interacting on the landscape. 

Image: Bumble Bee Research Colonies at a field site in the Cache Valley, Utah are protected behind a solar powered electric fence. The green box contains micro SD cards to record data from the traffic gates which are battery powered.

​No research project is without challenges and this project has had a few

• COVID safety and restrictions needed navigating.
• Trade issues made it impossible to get the needed technology to monitor bee activity, which left the lab to develop their own entrance gates and monitoring technology.
• Drought conditions required removing the honey bees earlier than planned, along with some of the bumble bees and mason bees.

 
Despite these challenges, the researchers collected the needed data and the project will continue through 2022. This project is an important step towards a more comprehensive understanding of honey bee and native bee interactions. This unique combination of experienced researchers, technology, and beekeeper support may help us learn how best to support harmonious, healthy bee populations through management of land and bees.

Authors:  Sharah Yaddaw, Communications Director, Project Apis m. 
                 Danielle Downey, Executive Director, Project Apis m.

References:
 
(1)   VanEngelsdorp, Dennis & Meixner, Marina. (2009). A Historical Review of Managed Honey Bee Populations in Europe and the United States and the Factors that May Affect Them. Journal of invertebrate pathology. 103 Suppl 1. S80-95. 10.1016/j.jip.2009.06.011. 

(2)   USDA- NASS Honey Survey, 2021
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(3)  Pollinators in Peril, A systematic status review of North American and Hawaiian native bees Kelsey Kopec & Lori Ann Burd • Center for Biological Diversity • February 2017