Pollen-mimicking, enzyme-loaded microparticles to reduce organophosphate toxicity in managed pollinators

Abstract

Pollinators support the production of 87 of the leading food crops worldwide and contribute over $15 billion to U.S. farm income. Organophosphates are a heavily used group of insecticides that pollinators can be exposed to, especially during crop pollination. Exposure to lethal or sub-lethal doses can impair fitness of wild and managed bees, risking pollination quality and food security. Here, we report a low-cost, scalable in vivo detoxification strategy for organophosphate insecticides involving encapsulation of phosphotriesterase (OPT) in pollen-mimicking microparticles (PMMs). We developed uniform and consumable PMMs capable of loading OPT at 90% efficiency and protecting OPT from degradation in the pH of a bee gut. Microcolonies of bumble bees (Bombus impatiens) fed malathion-contaminated pollen patties demonstrated 100% survival when fed OPT-PMMs but 0% survival with OPT alone and 0% survival with plain sucrose within 5 and 4 days, respectively. Thus, the detrimental effects of malathion were eliminated when bees consumed OPT-PMMs. This design presents a versatile and scalable treatment for managed pollinators to reduce risk from organophosphate insecticides, which can be integrated into supplemental feeds such as pollen patties or dietary syrup.

Comparative Acute Toxicity and Safety Indices of Organophosphate Insecticides on Apis mellifera

“…Concentrations ranging from 0.005% to 0.07% resulted in considerable bee mortality, with the highest mortality rates observed at concentrations of 0.05% and 0.07%. These findings align with previous research by Attri and Sharma (1969), Kumar and Gupta (2007), Aupinel et al (2007), Ratnakar et al (2017), Chen et al (2020), Dai et al (2019), andYang et al (2019), which highlight the toxic effects of dimethoate on honeybee populations. Furthermore, the study underscores the potential synergistic effect of dimethoate with other pesticides, as observed by Calatayud-Vernich et al (2016).…”