4 Chapter 1: Overview of Mason Bee Management
The general practices for managing populations of mason bees are similar, regardless of the species and/or cropping system you are interested in. Many of the management practices you will read about here have been adapted from management practices developed for Western populations of the blue orchard bee, Osmia lignaria.
The video below roughly outlines the steps required for successful management of mason bee populations. Notably, there are many adaptations and alternative tools/materials available for managing this pollinator – we will review this in subsequent chapters.
While reviewed in the above video, let’s take a minute to reflect on management requirements and considering throughout the calendar year.
If you are just getting started with mason bees, you are probably receiving them as cleaned, loose cocoons in the Spring, leading up to bud break in your orchard.
Bee Hotels: Give your bee hotel guests a four-star experience!
Just as managed honey bee colonies require regular inspections and seasonal management, so too do bee hotels.
Providing care to solitary bees requires regular attention and management throughout the year. Not only does this statement apply to orchardists, but also to all backyard gardeners and community scientists who maintain bee hotels on public or private lands. In nature, wild populations of mason bees do not nest gregariously in large groups, which can attract predators and parasites to invade these high density nesting locations. Repeated use of nesting reeds or other materials over many years can lead to the accumulation of pathogens such as chalkbrood which can kill developing larvae and spread quickly among nesting tunnels.
It is true that mason bees and other above ground, cavity-nesting species can benefit from the provisioning of bee hotels, especially in developed areas where access to natural nesting habitat many be limited. However, please be aware that by installing a bee hotel, you are accepting responsibility for your resident bees’ welfare and the welfare of their bee neighbors. Be thoughtful in the upkeep and maintenance of your hotels; specific maintenance actions may change depending on if your bee hotels are designed to attract/support a particular species or the wider community of pollinators in your area.
At a minimum – here are some essential steps for responsible upkeep of any bee hotel
- Replace wood blocks or other used nesting substrates every 2 years. Many bee hoteliers sanitize and repurpose grooved, stackable wooden boards (pictured) via scrubbing the board interiors with a 5% bleach solution and/or flame sterilization to eradicate accumulated bacteria or fungal spores (this is also an acceptable, alternative practice).
- Do not keep your nesting materials outside year-round. Make the nesting tunnels available to the bees at the time you know they are active, then remove and store completed nest inside an organza bag, and in an unheated shed or garage until the following spring. If your hotel is intended to service mason bees or leaf-cutting bee exclusively, bee cocoons should be removed and cleaned of debris and parasites in the late fall prior to overwintering. This step is especially critical for mason bee management, given the recent introduction of the invasive Houdini fly from Europe and the devastating consequences of their occurrence on mason bee survival.
- Predation from rodents and/or birds can be common, especially for larger bee hotels. Indeed, bee hotels installed at the Arboretum at Penn State experienced a total 25% predation rate from mice in its first year after installation in 2022. This loss could have been avoided with the installation of predator-resistant, 1/2-in hardware cloth screens over the bee hotel entrance (which is know implemented as a best practice).
