An evidence-based rationale for a North American commercial bumble bee clean stock certification program

Abstract

The commercial production and subsequent movement of bumble bees for pollination of agricultural field and greenhouse crops is a growing industry in North America and globally. Concerns have been raised about the impacts of pathogen spillover from managed bees to wild pollinators, including from commercial bumble bees. We recommend development of a program to mitigate disease risk in commercial bumble bee production, which will in turn reduce disease stressors on wild pollinators and other insects. We provide recommendations for the components of a clean stock program with specific best management practices for rearing commercial bumble bees including related products such as wax, pollen, and nesting material.

Endosymbionts that threaten commercially raised and wild bumble bees (Bombus spp.)

“…Endosymbionts are only one category of parasites and pathogens that can affect bumble bees, and we address elsewhere the ectosymbionts that can also infect them (Evans et al 2023), as well as the potential risk that hive products such as wax and pollen pose to wild bumble bee and other pollinators. Together, this large number of bumble bee symbionts, in the context of a large and growing national and international commercial trade in these important pollinators, demonstrates the need for regulations that will help to prevent their spread, and the associated risk to wild pollinators (Strange et al 2023).…”

“…Additionally, we use the term "parasite" broadly to refer to organisms of all taxa, including viruses, that sustain themselves at the expense of their hosts and have the potential to cause harm to their hosts, a definition which, for our purposes, also encompasses the term "pathogen". Here we focus on known bumble bee endosymbionts; a review of known bumble bee ectosymbionts can be found in Evans et al (2023). Recommendations for implementing a clean stock program to detect and prevent the spread of parasites of concern in commercial rearing facilities that pose a threat to wild bees can be found in Strange et al (2023).…”

“…Here we focus on known bumble bee endosymbionts; a review of known bumble bee ectosymbionts can be found in Evans et al (2023). Recommendations for implementing a clean stock program to detect and prevent the spread of parasites of concern in commercial rearing facilities that pose a threat to wild bees can be found in Strange et al (2023).…”

“…We are still discovering the extent and frequency of parasite spread to wild communities through commerce, and the consequences of these introductions for native bees. As a prelude to potential regulation, such as a "clean stock" mandate that bees be certified as parasite-free before being shipped (Strange et al 2023), it is important to know the diversity of known bumble bee endosymbionts, their impacts on hosts (when known), and potential mechanisms for preventing future introductions. Here we review the literature and describe the diversity, pathology, and detection methods for bumble bee viruses, bacteria, protozoans, fungi, and nematodes, as well as associated knowledge gaps.…”

Parasites, parasitoids, and hive products that are potentially deleterious to wild and commercially raised bumble bees (Bombus spp.) in North America

“…Perhaps the good news is that we now have a growing body of literature about the symbionts that are associated with both honey bees and bumble bees, that we have methods for detecting and identifying them, and can therefore manage the bees in ways that can reduce transmission. The severity of the negative effects of some of these symbionts, and the fact that they can be transmitted from managed bees to wild bees (Colla et al 2006) provide incentive for development of management techniques and policies that will minimize future problems for this important group of pollinators (Strange et al 2023).…”