Non-Apis Bee Exposure Workshop: Industry Participants’ View

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The use of pesticides, as formulated products, and their active ingredients are regulated to ensure that products are effective in crop protection, and at the same time, safe for humans and the environment. Because nontarget organisms, such as bees, can be exposed to pesticides, a comprehensive body of legislation has been established in multiple countries to evaluate the safety of their uses. According to those regulations, pesticides should be authorized only in ways that do not pose an unacceptable risk to bees. For this purpose, each pesticide must pass a bee risk assessment during the authorization process (also called registration) before it can be used. The crop protection industry develops tools for farmers, so that they can effectively protect their crops from pests and diseases while avoiding unintentional effects to the environment, such as causing harm to pollinators and the availability of healthy bees. Industry must comply with pesticide regulations applicable in each country or region while is also engaging in stewardship programs with multiple stakeholders, such as farmers, researchers, government agencies, beekeepers, and conservation groups, to promote good pesticide management practices and bee health. Risk assessment procedures established by regulatory agencies are designed to inform risk management decisions, ensuring that approved uses of pesticides are compatible with the protection of bees. If a potential risk is identified, appropriate risk mitigation measures are implemented. Regulatory agencies such as the United States Environmental Protection Agency (USEPA), Health Canada Pest Management Regulatory Agency (PMRA), California Department of Pesticide Regulation (CDPR), European Food Safety Authority (EFSA), Brazilian Institute of the Environment and Renewable Natural Resources (IBAMA), and Australian Pesticides and Veterinary Medicines Authority (APVMA) have defined protection goals related to bees. They generally include the maintenance of pollination services and hive products (e.g., honey, wax, propolis), and bee biodiversity (EC 2009; USEPA et al. 2012, 2014; APVMA 2017; Cham et al. 2017). Although these protection goals are considered protective for all bee species, the means to achieve them across Apis and non-Apis bees in the regulatory context may differ. To date, most pesticide-regulatory assessments rely on the honey bee as a surrogate species for the wide range of bee species associated with agricultural and horticultural crops worldwide. The Western honey bee (Apis mellifera L.; Hymenoptera: Apidae) was selected by regulatory agencies as a suitable model due to its availability and ability to thrive under laboratory testing conditions. It is assumed that data for individual honey bee adults or larvae, as well as honey bee colonies, can provide relevant information on the potential effects and exposure of pesticides to non-Apis species (solitary bees, bumble bees, and stingless bees). However, uncertainties exist regarding the extent to which pesticide exposure data for honey bees can be considered protective for non-Apis bees. Honey bees and non-Apis bees differ due to their respective life-history traits (i.e., body size, sociality, flight season, voltinism, floral specialization, and nesting behavior), which may result in different ecological impacts from pesticide use (Tasei 2002; Brittain et al. 2011). There are fewer published efforts defining pesticide exposures to solitary and social non-Apis bee species than there are for honey bees. In terms of exposure, there is a lack of documented scenarios to account for the differences between Apis and non-Apis life-history characteristics, creating uncertainty within the regulatory community as to whether honey bee exposure estimates are protective for other bee species as regards exposure and related risks. On this basis, and under the initiative of the Pollinator Research Task Force, an international workshop was held on 10–12 January 2017 in Washington, DC. The workshop was organized as a tripartite effort among regulatory agencies, academia, and the crop protection industry. Forty bee researchers and risk assessors from 10 different countries gathered to discuss the state of science on pesticide exposure to non-Apis bees. The objectives of the workshop were to identify potential exposure routes to non-Apis bees (solitary bees, bumble bees, and stingless bees) and compare them to routes of exposure currently parameterized for honey bees in different regulatory risk assessment schemes. The exposure routes were classified as primary or secondary, based on the participants’ collective expert judgment. Considering the importance and the sensitive nature of pesticide risks to bee health, this meeting also offered the opportunity to build trust and reliability in a pollinator risk assessment that may not be familiar by all participants, but which is very often under scrutiny by public opinion. Participants were invited to reduce uncertainties and ambiguities, clarify facts, and identify research needs that can better inform future bee risk assessment and risk management decisions. Further discussions on non-Apis pesticide exposure risks occur in a series of accompanying articles, but one of the conclusions of the workshop was that the dietary exposure through consumption of pollen and nectar by adults and larvae is the most important exposure route for honey bees and non-Apis bees. Here, we provide an additional point of view from industry scientists (users of the pollinator risk assessments) of the multiple conservative exposure assumptions in the current honey bee risk assessment, and whether they may adequately cover the potential dietary exposure for individual non-Apis bees. In the honey bee risk assessment methodology, a tiered approach is used, where tier 1 is based on laboratory toxicity data, aiming at measuring the intrinsic toxicity of a substance to adult or developing stages, and modeled exposure estimates to individual honey bees. Tier 1 is intentionally very conservative and serves as a screening method for determining whether additional higher-tier testing at the colony level is needed to inform the risk assessment. Consequently, in tier 1 assessments, pesticide exposures are estimated based on high-end daily pollen and nectar consumption rates of each honey bee caste. For adults, the screening method relies upon nectar-foraging bees, which consume more than other adult worker bees (Rortais et al. 2005). This consumption rate is comparable to the consumption rates of adult drones and will be protective for adult queens as well. Although the queen consumes more food daily than adult workers and drones, she consumes only royal jelly, which, if pesticide residues do exist, contains orders of magnitude less pesticide residues than that consumed by workers (USEPA et al. 2012; Böhme et al. 2017). Based on overly conservative energy demands of foraging flights (Rortais et al. 2005), coupled with a rather low estimate for sugar content in nectar of 30% across all crops in the United States, Canada, and Brazil (15% in Europe), the agencies assume that an individual forager bee will consume 292 mg nectar per day (853 mg in Europe), the highest consumption compared to other life stages. On the basis of an exposure of adults of three times bodyweight of nectar per day (128 mg average body weight according to Johansen and Mayer,1990), a rather low estimate for sugar content in nectar of 30%, no other source of food, and a continuous foraging for 10 h/d with 80% of time flying, the risk assessment assumes 150 flights/d (Rortais et al. 2005). Data from tagged bees in real world conditions demonstrate over a period of days bees forage on canola 2–3 times per day (Thompson et al. 2016); even 20–30 foraging flights would mean this is a fivefold overestimate. For larvae, the screening method relies upon consumption data for a 5-d old larva, which consumes the most foo

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