Align regulation with environmental reality and policy Among aspects of agricultural intensification that have been criticized for negative impacts on biodiversity (1, 2), pesticides have been linked to declines in insects, birds, and biodiversity in aquatic systems (3–5). If pesticide use is to blame, even partially, then this raises questions both about pesticide use and the regulatory procedures that are used to protect the environment (4). Environmental risk assessment (ERA) of pesticides does not account for many stressors that have intensified in recent years, such as climate change, habitat destruction, and increasing landscape homogeneity, the combination of which can aggravate effects of pesticides in nature. We describe how several assumptions underlying ERA may not hold in modern intensive agricultural landscapes, and the interaction among assumption violations may account for observed declines in biodiversity. Using European contexts to exemplify these global concerns, we review how regulatory ERA for pesticides has fallen out of step with scientific knowledge (4) and societal demands for sustainable food production and suggest systematic and recently feasible changes for regulation.

https://science.sciencemag.org/content/sci/367/6476/360.full.pdf

Overhaul environmental risk assessment for pesticides.

Global concern over widely documented declines in pollinators1–3 has led to the identification of anthropogenic stressors that, individually, are detrimental to bee populations4–7. Synergistic interactions between these stressors could substantially amplify the environmental effect of these stressors and could therefore have important implications for policy decisions that aim to improve the health of pollinators3,8,9. Here, to quantitatively assess the scale of this threat, we conducted a meta-analysis of 356 interaction effect sizes from 90 studies in which bees were exposed to combinations of agrochemicals, nutritional stressors and/or parasites. We found an overall synergistic effect between multiple stressors on bee mortality. Subgroup analysis of bee mortality revealed strong evidence for synergy when bees were exposed to multiple agrochemicals at field-realistic levels, but interactions were not greater than additive expectations when bees were exposed to parasites and/or nutritional stressors. All interactive effects on proxies of fitness, behaviour, parasite load and immune responses were either additive or antagonistic; therefore, the potential mechanisms that drive the observed synergistic interactions for bee mortality remain unclear. Environmental risk assessment schemes that assume additive effects of the risk of agrochemical exposure may underestimate the interactive effect of anthropogenic stressors on bee mortality and will fail to protect the pollinators that provide a key ecosystem service that underpins sustainable agriculture. A meta-analysis of studies in which bees were exposed to combinations of agrochemicals, nutritional stressors and/or parasites revealed evidence for synergistic effects on mortality when bees were exposed to multiple agrochemicals at field-realistic levels.

Agrochemicals interact synergistically to increase bee mortality

Systemic insecticides, such as neonicotinoids, are a major contributor towards beneficial insect declines. This has led to bans and restrictions on neonicotinoid use globally, most noticeably in the European Union, where four commonly used neonicotinoids (imidacloprid, thiamethoxam, clothianidin and thiacloprid) are banned from outside agricultural use. While this might seem like a victory for conservation, restrictions on neonicotinoid use will only benefit insect populations if newly emerging insecticides do not have similar negative impacts on beneficial insects. Flupyradifurone and sulfoxaflor are two novel insecticides that have been registered for use globally, including within the European Union. These novel insecticides differ in their chemical class, but share the same mode of action as neonicotinoids, raising the question as to whether they have similar sub-lethal impacts on beneficial insects. Here, we conducted a systematic literature search of the potential sub-lethal impacts of these novel insecticides on beneficial insects, quantifying these effects with a meta-analysis. We demonstrate that both flupyradifurone and sulfoxaflor have significant sub-lethal impacts on beneficial insects at field-realistic levels of exposure. These results confirm that bans on neonicotinoid use will only protect beneficial insects if paired with significant changes to the agrochemical regulatory process. A failure to modify the regulatory process will result in a continued decline of beneficial insects and the ecosystem services on which global food production relies.

https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2020.1265

Do novel insecticides pose a threat to beneficial insects

Wild and managed bees are essential for global food security and the maintenance of biodiversity. At present, the conservation of wild bees is hampered by a huge shortfall in knowledge about the trends and status of individual species mainly due to their large diversity and variation in life histories. In contrast, the managed Western honey bee Apis mellifera is one of the best studied and monitored insects in existence. Since similar drivers may be relevant for the decline of wild bees and losses of managed honey bees, this raises the possibility that monitoring of honey bees may help to detect threatened regions for wild bees, thereby fostering urgently required conservation measures. However, this possible relationship has not yet been explicitly tested for. Moreover, research currently focused on honey bees as a model species may yield important insights into wild insect susceptibility to stressors and vice versa. Here we use the bees of Europe as a model to show that managed honey bees are not suitable surrogates for detecting declines in wild bees. A direct comparison of the response of wild bees and honey bees to the same threats (nutritional deficiencies, parasites and pathogens, pesticides, and a changing climate) shows that, whilst some of their responses may be similar at the individual level, when considered at the reproductive level (individuals versus colonies), many of their responses diverge. These results reinforce the need for basic research into wild bee biology, the need for national monitoring schemes for wild bee populations, and the call for conservation actions tailored to the individual ecologies of wild bee species.

/pdf/managed-honey-bees-as-a-radar-for-wild-bee-decline-4qyirvrqca.pdf

Managed honey bees as a radar for wild bee decline

Pesticides in honey bee colonies: Establishing a baseline for real world exposure over seven years in the USA.

https://hal-ineris.archives-ouvertes.fr/ineris-03319073/document

Investigating combined toxicity of binary mixtures in bees: Meta-analysis of laboratory tests, modelling, mechanistic basis and implications for risk assessment.

Jose Cortinas-Abrahantes

Papers

Investigating combined toxicity of binary mixtures in bees: Meta-analysis of laboratory tests, modelling, mechanistic basis and implications for risk assessment.