An “audit” of mason bee shipments for quality and potential contaminants

Mason bees, genus Osmia, have been used for decades as orchard pollinators in the western United States, which led to the development of an industry devoted to supplying them. However, recent interest in native bees amongst the general public has led to Osmia being increasingly sold online and shipped to consumers in new locations across the country. While the interest in native bees is positive, this practice may have unintended negative effects. Unwary producers could ship invasive Osmia species attributed to the decline of natives to new regions. Also, incorrectly overwintered bees or orders with improper sex ratios may be less effective at pollinating, giving consumers a negative opinion of the industry. Our objective is to assess the potential impact of the online Osmia selling industry by examining the contents of orders purchased from a wide variety of vendors. Upon reception, orders were maintained in separate ventilated containers at winter temperatures until early April, when emergence was induced at room temperature. Emerged bees were removed from containers and stored for identification. Order contents will be identified to species to assess for invasive Osmia, and any parasites will also be identified. Sex ratio and the number of successfully emerged bees will also be determined as a measure of order quality. This data will allow researchers to better evaluate the potential impacts of the Osmia selling industry, as many producers are not clear regarding how their bees are handled, or in some cases what species they contain.