Revolutionizing Osmia Propagation: Exploring Sustainable Methods for Raising Osmia lignaria in Enclosures

Commodities

• Fruits: apples, cherries
• Nuts: almonds
• Animals: bees

Practices

• Crop Production: pollination, pollinator habitat, pollinator health

The blue orchard bee (BOB), Osmia lignaria, is a native solitary bee that is rapidly becoming a large-scale commercial pollinator of several fruit and nut crops, such as almonds and sweet cherries (Bosch and Kemp 2001; Embry 2018).  These bees have been demonstrated to be effective pollinators in conjunction with honey bees (Brittain et al. 2013).  BOBs are currently propagated in small batches on private properties with native vegetation.  Growth in supply of the bees has not kept up with demand because these bees do not propagate/reproduce well in commercial orchards. This project will improve upon existing methods of mass rearing and make Osmia propagation more sustainable and economical for both the bee producers and the growers who use this pollination service. Prior commercial R&D demonstrated that cage propagation could lead to replication rates up to 5-fold annually in screened cages in California.  However, California projects were hampered by nearby pesticide applications and heavy weed pressure.  For this project, our team includes the largest current supplier of Osmia bees in the industry, as well as leading research and extension experts on Osmia. Our goal is to develop practices that would enhance what is already known about the behavior and biology of this species to maximize healthy reproductive output without burdening the ecosystem. Our first enclosure will be assembled on farmland owned by Watts, in southwestern Idaho that has minimal weed pressure, a buffer region protecting it from neighboring pesticide applications, and we will test various wildflower species, planting timings, and stocking densities to optimize bee reproductive success and annual consistency.  We will measure bee fitness (growth rate, sex ratio and mass) of the offspring and compare that to traditional propagation on native vegetation in the open.  With three seasons of testing, we are confident that we will have developed reliable methods for consistent annual increases of the bees which can then be replicated for further growth.  While this research will benefit Watts Solitary Bees initially, we will share our data and educate other bee producers about raising their bees using this method. From this project we hope to provide Osmia producers with appropriate seed mixes for the western United States, identifying ideal stocking densities, and understand the level of natural predators in this system.

Objective 1 (Y1 – Y2): Assess the optimal seed mix for both the attractiveness/nutrition of Osmia lignaria and the feasibility and success of growing these mixes in the Great Basin region.

Objective 2 (Y2 – Y3): Determine the appropriate stocking density of O. lignaria in field cages and assess the ability to scale up the stocking density to large enclosures.

Objective 3 (Y1 – Y3): Determine yearly behavioral changes of the bee and assess yearly variation in the native pest communities.