Initial recommendations for higher‐tier risk assessment protocols for bumble bees, Bombus spp. (Hymenoptera: Apidae)

Abstract

Global declines of bumble bees and other pollinator populations are of concern because of their critical role for crop production and maintenance of wild plant biodiversity. Although the consensus among scientists is that the interaction of many factors, including habitat loss, forage scarcity, diseases, parasites, and pesticides, potentially plays a role in causing these declines, pesticides have received considerable attention and scrutiny. In response, regulatory agencies have introduced more stringent pollinator testing requirements for registration and reregistration of pesticides, to ensure that the risks to pollinators are minimized. In this context, guidelines for testing bumble bees (Bombus spp.) in regulatory studies are not yet available, and a pressing need exists to develop suitable protocols for routine higher-tier studies with these non-Apis sp., social bees. To meet this need, Bayer CropScience LP, Syngenta Crop Protection LLC US, and Valent USA. Corporation organized a workshop bringing together a group of global experts on bumble bee behavior, ecology, and ecotoxicology to discuss and develop draft protocols for both semi-field (Tier II) and field (Tier III) studies. The workshop was held May 8-9, 2014, at the Bayer Bee Care Center, North Carolina, USA. The participants represented academic, consulting, and industry scientists from Europe, Canada, the United States, and Brazil. The workshop identified a clear protection goal and generated proposals for basic experimental designs, relevant measurements, and endpoints for both semifield (tunnel) and field tests. These initial recommendations are intended to form the basis of discussions to help advance the development of appropriate protocol guidelines.

Comparison of buckwheat, red clover, and purple tansy as potential surrogate plants for use in semi-field pesticide risk assessments withBombus impatiens

“…Pesticides that demonstrate the potential for hazard in Tier I studies are then assessed further via Tier II (semi-field) and/or Tier III (field) studies. Standardized risk assessment protocols exist for honey bees (OECD, 1998a; OECD, 1998b; OECD, 2007; OECD, 2010; EPPO, 2010), but semi-field and field methods have yet to be established for bumble bees (Cabrera et al, 2016). Preliminary semi-field and field risk assessment protocols and critical assessment endpoints for bumble bees recently have been proposed (Cabrera et al, 2016), and these methods now must be validated and refined.…”

“…In semi-field studies, colonies are caged to pesticide-treated flowering plants in the field to determine if the pesticide has effects at the colony level (Cabrera et al, 2016). The surrogate plant used must be highly attractive to foragers to ensure colony exposure to the test compound.…”

“…Additionally, the plants must produce an adequate supply of quality nectar and pollen to sustain the bees and promote optimal colony development during the test period. However, we currently lack data on the development and behaviour of bumble bees on different plants potentially used in semi-field pesticide risk assessment studies (Cabrera et al, 2016). …”

“…common), red clover ( Trifolium pratense ), and purple tansy ( Phacelia tanacetifolia ) as potential surrogate plants for semi-field pesticide studies with the common eastern bumble bee ( Bombus impatiens Cresson). We focussed on these plants because they are attractive to bumble bees (Williams, 1997; Carreck & Williams, 2002; Pontin et al, 2006; Jacquemart, Gillet & Cawoy, 2007; Colla & Dumesh, 2010; Bartomeus et al, 2014), and purple tansy has previously been used in semi-field studies with bees (Cabrera et al, 2016). Bombus impatiens is abundant throughout eastern Canada and United States, and currently is the only bumble bee available commercially for crop pollination in North America.…”

“…Bombus impatiens is abundant throughout eastern Canada and United States, and currently is the only bumble bee available commercially for crop pollination in North America. These attributes make it a useful surrogate species for use in bumble bee pesticide toxicity studies in North America (Cabrera et al, 2016). We compared B. impatiens foraging activity and colony development on small flowering plots of each plant type to determine if the plants varied in their attractiveness to foragers and/or their ability to sustain whole colonies under semi-field conditions.…”