Ecological traits interact with landscape context to determine bees’ pesticide risk

Abstract

Widespread contamination of ecosystems with pesticides threatens non-target organisms. However, the extent to which life-history traits affect pesticide exposure and resulting risk in different landscape contexts remains poorly understood. We address this for bees across an agricultural land-use gradient based on pesticide assays of pollen and nectar collected by Apis mellifera, Bombus terrestris and Osmia bicornis, representing extensive, intermediate and limited foraging traits. We found that extensive foragers (A. mellifera) experienced the highest pesticide risk—additive toxicity-weighted concentrations. However, only intermediate (B. terrestris) and limited foragers (O. bicornis) responded to landscape context—experiencing lower pesticide risk with less agricultural land. Pesticide risk correlated among bee species and between food sources and was greatest in A. mellifera-collected pollen—useful information for future postapproval pesticide monitoring. We provide foraging trait- and landscape-dependent information on the occurrence, concentration and identity of pesticides that bees encounter to estimate pesticide risk, which is necessary for more realistic risk assessment and essential information for tracking policy goals to reduce pesticide risk.

Revised guidance on the risk assessment of plant protection products on bees (Apis mellifera, Bombus spp. and solitary bees)

“…Bees may be exposed to other mixtures e.g. when the bee foraging activity across the landscape creates a mixture of PPPs at the hive/colony/nest (Knapp et al., 2023 ) or spray tank mixtures where different types of PPPs are mixed that may involve certain combinations of concern with potential for synergistic effects (e.g. pyrethroids insecticides and azole fungicides, (Siviter et al., 2021 ).…”

Moving Past Neonicotinoids and Honeybees: A Systematic Review of Existing Research on Other Insecticides and Bees

“…Many of these taxa differ from honeybees in ways that influence insecticide-related risks. For example; differing life histories, sociality, nesting behaviour, foraging range and floral preference can impact the risk of exposure ( (Knapp et al, 2023); Willis Chan et al (2019), and genetic factors and body size can moderate the bees' sensitivity to insecticides (Devillers et al, 2003;Hayward et al, 2019), so that insecticide risk estimates for nonhoneybees cannot be accurately extrapolated from honeybees (Cresswell et al, 2012;Rundlöf et al, 2015;Woodcock et al, 2017). Thus, there is a clear need for more research to understand impacts of insecticides on wider, non-honeybee diversity.…”

Phytochemicals, Probiotics, Recombinant Proteins: Enzymatic Remedies to Pesticide Poisonings in Bees

“…For example, crops such as corn or soybean are commonly grown with neonicotinoid-coated seeds and subsequent herbicide use (e.g., glyphosate) in spring . In a landscape with more crop types and a greater diversity of pesticides applied, pesticide exposure is less predictable since honey bees can forage up to 10 km and come into contact with different types of pesticides simultaneously in surrounding landscapes. ,, In these landscapes with more diverse crops and varying pesticide uses, the development of detoxification solutions may be more complicated. ,, Beekeepers, especially commercial operators managing thousands of bee hives located in different apiary locations, face more uncertainties regarding detoxification strategies . While one constituent in a 3P treatment usually works to detoxify one set of pesticides, the challenge presented by complex exposure situations will not be resolved until a product composed of diverse constituents is developed to detoxify different pesticides …”

“…Those manageable wild, solitary bee species can aggregate in bare ground such as alkali bees ( Nomia melanderi ) or artificial cardboard or wooden cavity nests such as mason bees ( Osmia ) and leafcutter bees ( Megachile ), and one treatment can save hundreds or even thousands of individuals. Since solitary bees are more likely impacted by pesticides used in focal fields as they forage at a short distance under the direct impact of focal field pesticide use, more predictable benefits may be gained by applications of 3P. , Since aggregating bees can nest in the same area for years (e.g., Andrena vaga ), the identification of existing nesting locations or active reconstruction of conservation habitats would facilitate detoxification over a longer term. Restricting pesticide use around aggregations will reduce the level of potential exposures.…”